Infection Control and Barrier Precautions

• A pathogen is a disease-producing microorganism.
• Transmission is any mechanism by which a source or reservoir spreads a pathogen to a host.
• A reservoir is any person, animal, plant, soil, substance, or any combination in which an infectious agent lives and multiplies. The infectious agent depends on the reservoir for survival, and the reservoir provides a place where the pathogen can reproduce itself so it can be transmitted to a susceptible host.
• Susceptibility is a host's inability to resist infection from a specific pathogen.
• The common vehicle is a contaminated material, product, or substance that is an intermediate means by which an infectious agent is transported to two or more susceptible hosts.
• Colonization: An organism is present in a host, multiplying, but there is no host interference or interaction with the host.
• Host: An organism where another organism can live and potentially multiply.
• Infection: Invasion and multiplication by a microorganism. An infection may be local or systemic, begin as local and become systemic. The infection or the host response may cause no apparent host response or clinical signs and symptoms.
• The incubation period is the time between the beginning of an infection and the onset of signs and symptoms.
• Latent period: The time between infection and the onset of signs and symptoms in one case of the disease.

A chain of events and circumstances is required for infection to occur. These include:

1. A reservoir for the pathogenic organism
2. A means to exit the reservoir
3. A mode of transmission
4. A susceptible host, and
5. A mode of entry into the host.

Pathogenic organisms include bacteria, rickettsia, viruses, protozoa, fungi, or parasites. The characteristics of microorganisms that can cause infection and disease are:

• Pathogenicity: The ability of a microorganism to cause disease.
• Virulence: The degree of pathogenicity of a microorganism, i.e., how easily it can invade a host and the severity of the disease it can cause.
• Invasiveness: The ability of a microorganism to enter and move through tissue.
• Infectious dose: The number of microorganisms needed to initiate an infection.
• Organism specificity: Host preference of the infectious agent.
• Antigenic variation: The ability of an infectious organism to change its surface proteins to escape host defenses.
• Toxigenicity: The capacity to produce toxins.
• Resistance: A microorganism’s ability to develop resistance to antimicrobial agents.

The organism and its reservoir are the sources of infection. The organism must have the means to exit the reservoir. In an infected host, organisms exit through the respiratory tract, gastrointestinal tract, genitourinary tract, sexual transmission, or drainage from a wound. A transmission route is necessary to connect the source of infection to its new host.

Contact transmission can be direct or indirect.

Direct contact: Person-to-person contact. It can be skin-to-skin contact, sexual contact, and/or contact with infected body fluids like blood, respiratory secretions, or other infected body fluids.

Indirect contact: Usually contact with a harmless inanimate object. The infected inanimate object is called a fomite. Fomites can survive on objects and surfaces for a long time and be a potential source of infection for weeks and months, e.g., fomites containing norovirus and Clostridium difficile (C. difficile).

Droplet contact: It is a form of direct and indirect contact transmission. Large respiratory droplets carrying pathogens are expelled from the respiratory tract by coughing, sneezing, or talking. Droplets move through the air, but because of their size and the limited time they are airborne, they do not travel far and quickly settle on environmental surfaces. Contact with the contaminated surface, e.g., hand contact, and then contact of the hand to a mucous membrane spreads the pathogen from the surface to a host, meaning that direct contact can transmit respiratory droplets.

Droplet contact is how the influenza virus is spread. Droplet contact and transmission can also occur if someone is very close to an infected person who is coughing and/or sneezing, and the infected droplets inoculate mucous membranes of the eyes, nose, and/or mouth.

• Droplet nuclei: Residue of evaporated droplets that remain suspended in the air. Pathogens spread by airborne transmission include (but are not limited to) Mycobacterium tuberculosis and Varicella. Airborne transmission differs from the transmission of respiratory droplets in two ways:
  1. Airborne infectious particles stay in the air longer than infected respiratory droplets, and
  2. Airborne infectious particles travel much further than infected respiratory droplets.
• Dust: Particles in the air containing infectious agents.

The following table outlines the organism, transmission mode, and incubation period for the most common microorganisms and parasites.

The host must be susceptible to the infection for infection to occur. Factors influencing susceptibility include, but are not limited to:

• Number of organisms to which the host is exposed and the duration of exposure
• Age, the genetic constitution of the host, and general physical, mental, and emotional health and nutritional status of the host
• Status of hematopoietic systems; efficacy of the reticuloendothelial system
• Absent or abnormal immunoglobulins
• The number of T lymphocytes and their ability to function

Pregnant healthcare professionals are not known to be at greater risk of contracting bloodborne infections; however, infectious pathogens can be transmitted to the fetus.

The organism must have a portal of entry into the host for infection to occur. Portals of entry are the mucous membranes, non-intact skin, respiratory tract, gastrointestinal tract, genitourinary tracts, or a mechanism of introduction, such as a percutaneous injury or invasive device.

Enterobacteriaceae are gram-negative bacilli that are commonly found in the gastrointestinal tract. Common species of this family that cause infections include Enterobacter, Escherichia coli, and Klebsiella. Carbapenem-resistant Enterobacteriaceae (CRE) are resistant to the carbapenem family of antibiotics (doripenem, ertapenem, imipenem, and meropenem). These antibiotics are traditionally used to treat pathogens resistant to broad-spectrum antimicrobials (CDC, 2019c). CRE is spread through contact with infected surfaces, e.g., hands or contaminated medical equipment. Infections with CRE are particularly dangerous: they can spread rapidly, and the mortality rate in hospitalized patients can exceed 50% (CDC, 2019c). CRE infections usually do not occur in healthy people; they are more likely in hospitalized patients with compromised immune systems, mechanically ventilated patients, or those who have received multiple antibiotics. The incidence of CRE infections is increasing. Control and prevention of CRE infections should focus on the following:

1. Identifying colonized patients
2. Screening by taking stool, rectal and perirectal cultures, and wound cultures when appropriate
3. Strict adherence to handwashing protocol
4. Environmental cleaning
5. Patient and staff cohorting
6. Staff education
7. Using contact precautions (CDC, 2019c)

Staphylococcus aureus (S. aureus) is transmitted primarily via the hands of healthcare professionals and by direct contact with contaminated equipment and surfaces. Transmission is efficient, and S. aureus easily colonizes the skin and nares. Once colonized, the person faces the likelihood of infection when invasive procedures are performed. Methicillin-resistant S. aureus (MRSA) and oxacillin-resistant S. aureus (ORSA) are common causes of nosocomial infections in hospitals and extended care facilities (Pannewick et al., 2021).

MRSA colonization is quite common, so every patient must be assumed to have been exposed to or colonized with MRSA/ORSA. In addition, MRSA often contaminates medical equipment such as stethoscopes and environmental surfaces (Bhatta et al., 2022).

The Centers for Disease Control and Prevention (CDC) recommends strict adherence to Standard and Contact Precautions, personal protective equipment (PPE), and appropriate handling of medical devices and laundry if MRSA is of particular clinical or epidemiological significance (CDC, 2016b).

Vancomycin is the first-line drug for treating MRSA infections (Cong et al., 2019), but vancomycin-resistant S. aureus has developed (Cong et al., 2019). The susceptibility of S. aureus strains to vancomycin is determined by a minimum inhibitory concentration (MIC) test. The MIC measures the minimum amount of antimicrobial agent that inhibits bacterial growth in a test tube. Staph bacteria are classified as vancomycin susceptible (VSSA), vancomycin-intermediate (VISA), and vancomycin-resistant (VRSA) (Cong et al., 2019).

These infections must be reported to the CDC and the state health department. The following is guidance for patients infected with VISA or VRSA:

• They should be in a single room
• Contact Precautions and Standard Precautions are required
• Staff education is recommended
• Minimize the number of staff caring for the patient
• Flag the chart to alert staff of the situation (CDC, 2015b)

Enterococci are gram-positive bacteria. They are a normal part of the gastrointestinal and female genital tract flora (CDC, 2019i). It is a relatively weak pathogen but can produce significant infections if the patient is infected with vancomycin-resistant enterococcus (VRE). Treatment options for these infections are limited. People at risk for VRE infections include:

• Patients previously treated with vancomycin
• Patients in intensive care
• Patients who are immunocompromised
• Post-operative patients
• Patients with in-dwelling IV or urinary catheters (CDC, 2019i)

VRE is transmitted primarily via the hands of healthcare professionals and by direct contact with contaminated equipment and surfaces. Many approaches have been used to control VRE in healthcare settings. The methods used should be tailored to the clinical setting, the specific patient/patients involved, and the epidemiological characteristics of the situation. Contact Precautions and Standard Precautions should be used to prevent transmission of VRE (CDC, 2019i).

The Mycobacterium tuberculosis bacteria cause tuberculosis (TB), one of the oldest recognized infectious diseases. Multidrug-resistant tuberculosis (MDR-TB) is resistant to isoniazid and some second-line drugs. Extensively Drug-Resistant Tuberculosis (XDR-TB) is resistant to isoniazid, rifampin, and fluoroquinolones. XDR-TB is also resistant to at least one of three injectable second-line drugs, such as amikacin, kanamycin, or capreomycin (CDC, 2016a). The incidence of MDR-TB has increased in recent years due to poor compliance with prescribed drug regimens, inappropriate/incorrect prescribing, patient co-morbidities, and other risk factors (Bykov et al., 2022; CDC, 2016a).

Infection control measures should include separating the infected patient/patients, environmental controls, using Standard Precautions, Respiratory Hygiene/Cough Etiquette, Airborne Precautions, and staff use of particulate respirators (CDC, 2020l; CDC, 2019h).

Streptococcus pneumoniae (S. pneumoniae) is a commonly found pathogen in the upper respiratory tract. Infections with this pathogen are a common cause of pneumonia, meningitis, sepsis, bacteremia, and otitis media (Ryan, 2022), and S. pneumoniae infections are a leading cause of morbidity and mortality (CDC, 2015b). The elderly and the very young are the most susceptible to infection with S. pneumoniae(Ryan, 2022). Transmission is from infected respiratory droplets, which can be spread by close contact with an infected person who is coughing and/or sneezing (Ryan, 2022).

Penicillin-resistant and multidrug-resistant strains of this pathogen have emerged and are widespread in some communities (Ryan, 2022). A vaccine for the most common serotypes of S. pneumoniae is available, but vaccination rates are not optimal (Lu et al., 2021). Contact Precautions, Droplet Precautions, and Respiratory hygiene/Cough Etiquette should be used when caring for patients infected with this pathogen.

Acinetobacter baumannii (A. baumannii) is a bacterium usually found in the soil and water and on the skin of healthy people. Acinetobacter infections typically happen to hospitalized patients in ICUs, normally mechanically ventilated and post-operative patients, who have been hospitalized for a long time (CDC, 2019a). Community-acquired A. baumannii infections have occurred in immunocompromised people or those with chronic lung disease or diabetes (CDC, 2019a).

Nosocomial drug-resistant A. baumannii infections cause bacteremia, pneumonia, and UTIs (McKay et al., 2022). The morbidity and mortality rates associated with drug-resistant Acinetobacter infections are very high (Kim et al., 2022a), and outbreaks of these infections in healthcare facilities are difficult to control (Lashinsky et al., 2017).

Contact transmission is the primary way Acinetobacter spreads, so Contact Precautions and Standard Precautions, with particular attention to hand washing, are integral to controlling and preventing these infections. Because of the danger of these infections and the difficulty in containing outbreaks, patients who have an infection with drug-resistant Acinetobacter may need to be isolated, or their placement in the facility should be carefully considered.

Standard Precautions are strategies for protecting healthcare professionals, patients, and visitors from the transmission of pathogenic organisms. Standard Precautions also prevent patient-to-patient transmission and staff-to-patient transmission. Standard Precautions assume that all pre-existing patient infections cannot be identified. The primary underpinning of Standard Precautions is that all body fluids and secretions should be considered potentially infectious. Standard Precautions apply to nonintact skin and mucous membranes, blood, and all body fluids, secretions, and excretions, except sweat (in certain circumstances, sweat can be considered infectious). In some cases, such as with specific pathogens like HIV, a patient’s body fluids, like vomit, are only considered a risk for disease transmission if they contain visible blood. Additional precautions are based on highly transmissible or epidemiologically important pathogens.

Standard Precautions have six essential elements: Hand washing, the use of PPE, safe and proper disposal of contaminated material and equipment, safe injection practices, Respiratory Hygiene/Cough Etiquette practices, and the use of masks for insertion of catheters or injections into spinal or epidural spaces via lumbar puncture. The new elements of Standard Precautions that have been added since they were formulated were designed to focus on patient protection. These elements are Respiratory Hygiene/Cough Etiquette, safe injection practices, and masks for inserting catheters or injections into spinal or epidural spaces via lumbar puncture (Siegel et al., 2007).

Standard Precautions should be used in all patient care situations.

Transmission-Based Precautions are the infection control techniques and procedures that are used “. . . for patients who are known or suspected to be infected or colonized with infectious agents, including certain epidemiologically important pathogens, which require additional control measures to prevent transmission effectively. Since the infecting agent is usually unknown at admission, Transmission-Based Precautions are used. Transmission-Based Precautions are used according to the symptoms and etiology. Precautions are then modified when the pathogen is identified, or an infectious cause is ruled out” (Siegel et al., 2007). Transmission Precautions are used in addition to Standard Precautions, and Standard Precautions are used in all patient care situations (Siegel et al., 2007).

There are three types of Transmission Precautions: Airborne, Contact, and Droplet (Siegel et al., 2007).

Neutropenic precautions (also called protective environment) are implemented to protect immunocompromised patients. When chemotherapy patients have a neutrophil level <1000, neutropenic precautions are utilized (Evashwick et al., 2022). There are no universally used standards for neutropenic precautions (Evashwick et al., 2022; Lequilliec et al., 2017). The specific precautions needed may vary, depending on the patient’s condition (Siegel et al., 2007).

Conditions/Diseases that may require neutropenic precautions:

• Acquired immunodeficiency syndrome (AIDS)
• Agranulocytosis
• Burns
• Chemotherapy
• Hematopoietic stem cell transplantation
• Immunosuppressive therapy

Immunization is one method to reduce the transmission of communicable diseases. The following are recommendations for immunization based on age and exposure risk. Specifics and schedules for high-risk populations and catch-up immunizations are available from the CDC. Immunization schedules for adults are available from the CDC.

These recommendations for the immunization of healthcare personnel are from the CDC (CDC, 2016b):

• Hepatitis B - A 3-dose series of Recombivax HB or Engerix-B (dose #1 now, 2nd dose in 1 month, and the 3rd dose approximately five months after the 2nd) or a 2-dose series of Heplisav-B, with the doses separated by at least four weeks. An anti-HBs serologic test should be done 1-2 months after the final dose.
• Influenza – One dose of influenza vaccine every year.
• Meningococcal – Microbiologists routinely exposed to Neisseria meningitidis should get a meningococcal conjugate vaccine and serogroup B meningococcal vaccine.
• MMR – Those born in 1957 or later without the MMR vaccine and serologic evidence of immunity or prior vaccination will get two doses of MMR (1 dose now and the 2nd dose at least 28 days later). If you were born in 1957 or later and have not had the MMR vaccine, or if you don’t have a blood test that shows you are immune to rubella, only one dose of MMR is recommended. However, you may receive two doses because the rubella component is in the combination vaccine with measles and mumps. For those born before 1957, see the MMR ACIP vaccine recommendations.
• Poliomyelitis - Laboratory workers who handle specimens that might contain polioviruses should consider getting the polio vaccine, regardless of whether they were vaccinated during childhood. Healthcare workers who have close contact with patients who may have traveled to areas or countries with a high risk of polio should also consider getting the polio vaccine (CDC, 2018b).
• Tetanus, diphtheria, pertussis – Tdap once if never vaccinated, and a Td booster every ten years. Pregnant healthcare workers should get a dose of Tdap during each pregnancy.
• Varicella – Healthcare personnel with no evidence of immunity to varicella should be given two doses of the varicella vaccine four weeks apart.

Basic education has been briefly discussed in previous sections of the module, and its application to other parts of the infection control process will be covered below. The CDC and OSHA recommend that the healthcare facility or employer inform the staff of potential risks for exposure to infectious materials. The facility should also provide them with the education and equipment they need to prevent contamination of medical equipment and the environment and protect themselves and patients against contamination and infections.

Cleaning, disinfection, and sterilization are essential for infection control and maintaining a safe environment. These processes can be used singly or in combination. They are done using different tools and techniques, producing different results. In simple terms, sterilization is intended to kill all microorganisms, disinfection will kill/remove most microorganisms, and cleaning will physically remove surface contamination and debris.

• In general, reusable medical devices or patient-care equipment that typically enters sterile tissue,  the vascular system, or through which blood flows are considered critical items and should be sterilized before each use. Sterilization means using a physical or chemical procedure to destroy all microbial life, including highly resistant bacterial endospores. The primary sterilizing agents used in hospitals are a) moist heat by steam autoclaving, b) ethylene oxide gas, and c) dry heat. However, various chemical germicides (sterilants) have been used to reprocess reusable heat-sensitive medical devices and appear effective when used appropriately, e.g., according to the manufacturer's instructions. These chemicals are rarely used for sterilization but appear effective for high-level disinfection of medical devices that contact mucous membranes during use (e.g., flexible fiberoptic endoscopes).
• Heat-stable, reusable medical devices that enter the bloodstream or usually sterile tissue should always be reprocessed using heat-based sterilization methods (e.g., steam autoclave or dry heat oven).
• Laparoscopic or arthroscopic telescopes (optic portions of the endoscopic set) should be subjected to a sterilization procedure before each use; if this is not feasible, they should receive high-level disinfection. Heat-stable accessories to the endoscopic set, like trocars and operative instruments, should be sterilized by heat-based methods (e.g., steam autoclave or dry heat oven).
• At a minimum, reusable devices or items that touch mucous membranes should receive high-level disinfection between patients. These devices include reusable, flexible endoscopes, endotracheal tubes, anesthesia breathing circuits, and respiratory therapy equipment.
• Medical devices that require sterilization or disinfection must be thoroughly cleaned to reduce organic material or bioburden before being exposed to the germicide. The germicide and the device manufacturer's instructions should be followed closely.

Except in rare and unique instances, items that do not ordinarily touch the patient, or touch only intact skin, are not involved in disease transmission and generally do not necessitate disinfection between uses on different patients. These include crutches, bed boards, blood pressure cuffs, and other medical accessories. Consequently, depending on the particular equipment or item, washing with a detergent or using a low-level disinfectant may be sufficient when decontamination is needed. If non-critical items are grossly soiled with blood or other body fluids, a higher level of disinfection is required (Rutala & Weber, 2019).

Cleaning removes visible and surface contamination from an object; that is its primary purpose, and cleaning can be completed mechanically or with cleaners. Cleaning can also help disinfect, but the two processes are different. Cleaning is not intended to kill bacteria or other microorganisms. Disinfection destroys pathogenic organisms; disinfection cannot and does not eliminate all organisms.

The following information is from the CDC Guideline for Sterilization and Disinfection in Healthcare Facilities (Rutala & Weber, 2019).

• Remove visible organic residue (e.g., residue of blood and tissue) and inorganic salts with cleaning. Use cleaning agents that are capable of removing visible organic and inorganic residues.
• Clean medical devices as soon as practical after use (e.g., at the point of use) because soiled materials become dried onto the instruments. The instrument's dried or baked materials make removal more difficult and the disinfection or sterilization process less effective or ineffective.
• Perform manual cleaning (i.e., friction) or mechanical cleaning (e.g., ultrasonic cleaners, washer-disinfector, washer-sterilizers).
• If using an automatic washer/disinfector, ensure the unit is used following the manufacturer’s recommendations.
• Detergents or enzymatic cleaners should be compatible with the metals and other materials used in medical instruments.
• Ensure that the rinse step is adequate for removing cleaning residues to levels that will not interfere with subsequent disinfection/sterilization processes.
• Discard or repair equipment that no longer functions as intended or cannot be properly cleaned, disinfected, or sterilized.
• The rinse step should be adequate for removing cleaning residues to levels that will not interfere with subsequent disinfection/sterilization processes.
• Inspect equipment surfaces for breaks in integrity that would interfere with cleaning or disinfection/sterilization.
• Meticulously clean patient-care items with water and detergent or water and enzymatic cleaners before high-level disinfection or sterilization procedures.

• Cleaning and disinfecting environmental surfaces and patient rooms have been shown to decrease the incidence of hospital-acquired infections and to reduce environmental contamination with potentially dangerous microorganisms such as C. difficile, MRSA, and VRE (Rutala & Weber, 2016).
• Clean housekeeping surfaces (e.g., floors, tabletops) regularly when spills occur and when these surfaces are visibly soiled.
• Disinfect or clean environmental surfaces regularly (e.g. daily, three times per week) and when surfaces are visibly soiled.
• Follow manufacturers’ instructions for proper disinfecting with detergent products, such as recommended use-dilution, material compatibility, storage, shelf-life, and safe use and disposal.
• Clean walls, blinds, and window curtains in patient-care areas when these surfaces are visibly contaminated or soiled.
• Prepare disinfecting or detergent solutions as needed and replace these with fresh solutions frequently (e.g., replace floor mopping solution every three patient rooms, and change no less often than at 60-minute intervals or according to the facility’s policy).
• Decontaminate mop heads and clean cloths regularly to prevent contamination.
• Use a one-step process and an EPA-registered hospital disinfectant designed for housekeeping purposes in patient care areas where:
  • uncertainty exists about the nature of the soil on the surfaces (e.g., blood or body fluid contamination versus routine dust or dirt), or
  • uncertainty exists about the presence of multidrug-resistant organisms on such surfaces
• Detergent and water are adequate for cleaning surfaces in non-patient care areas.
• Do not use high-level disinfectants/liquid chemical sterilants to disinfect non-critical surfaces.
• Wet-dust horizontal surfaces regularly, e.g., three times weekly, using clean cloths moistened with an EPA-registered hospital disinfectant or detergent. Use the disinfectant or detergent as per the manufacturer’s recommendations.
• According to the label’s safety precautions and use directions, disinfect non-critical surfaces with an EPA-registered hospital disinfectant. Most EPA-registered hospital disinfectants have a label contact time of 10 minutes. However, many scientific studies have demonstrated the efficacy of hospital disinfectants against pathogens with a contact time of at least 1 minute.
• The user must follow all applicable label instructions on EPA-registered products by law. Suppose the user selects exposure conditions that differ from those on the EPA-registered product label. In that case, the user assumes liability for any injuries resulting from off-label use and is potentially subject to enforcement action.
• Do not use disinfectants to clean infant bassinets and incubators while these items are occupied. If disinfectants are used for the terminal cleaning of infant bassinets and incubators, thoroughly rinse the surfaces of these items with water and dry them before they are reused.
• Promptly clean and decontaminate spills of blood and other potentially infectious materials. Discard blood-contaminated items in compliance with federal regulations.
• Implement the following procedures for site decontaminating blood spills or other potentially infectious materials (OPIM). Use protective gloves and other PPE when sharps are involved. Use forceps to pick up sharps and discard these items in a puncture-resistant container appropriate for this task.
• Areas contaminated with blood spills should be disinfected using an EPA-registered tuberculocidal agent or a registered germicide on the EPA's D and E-list.
• Disinfect areas contaminated with blood spills using an EPA-registered tuberculocidal agent, a registered germicide on the EPA Lists D and E, i.e., products with specific label claims for HIV or HBV or freshly diluted hypochlorite solution.
• If sodium hypochlorite solutions are selected, use a 1:100 dilution (e.g., 1:100 dilution of a 5.25-6.15% sodium hypochlorite provides 525-615 ppm available chlorine) to decontaminate nonporous surfaces after a small spill (e.g., <10 mL) of either blood or OPIM.
• If a spill involves large amounts (e.g., >10 mL) of blood or OPIM, or involves a culture spill in the laboratory, use a 1:10 dilution for the first application of hypochlorite solution before cleaning to reduce the risk of infection during the cleaning process (Rutala & Weber, 2019).
• Follow the decontamination process with terminal disinfection, using a 1:100 dilution of sodium hypochlorite.
• If the spill contains large amounts of blood or body fluids, clean the visible matter with disposable absorbent material and discard the contaminated materials in appropriate, labeled containment.
• Use gloves and PPE that is appropriate for the task.
• In units with high rates of endemic C. difficile infection or an outbreak setting, use dilute solutions of 5.25%–6.15% sodium hypochlorite for routine environmental disinfection (Rutala & Weber, 2019). Currently, no products are EPA-registered specifically for inactivating C. difficile spores.
• Suppose chlorine solution is not prepared fresh daily. In that case, it can be stored at room temperature for up to 30 days in a capped, opaque plastic bottle with a 50% reduction in chlorine concentration after 30 days of storage (e.g., 1000 ppm chlorine [approximately a 1:50 dilution] at day 0 decreases to 500 ppm chlorine by day 30).
• An EPA-registered sodium hypochlorite product is preferred, but generic versions of sodium hypochlorite (e.g., household chlorine bleach) can be used (Rutala & Weber, 2019).

Sterilize critical medical and surgical devices and instruments that typically enter sterile tissue, the vascular system, or a sterile body fluid flow (e.g., blood) before using them on/for a patient (Rutala & Weber, 2019). Provide, at a minimum, high-level disinfection for semi-critical patient-care equipment (e.g., gastrointestinal endoscopes, endotracheal tubes, anesthesia breathing circuits, and respiratory therapy equipment) that touches either mucous membranes or nonintact skin (Rutala & Weber, 2019).

Perform low-level disinfection for non-critical patient-care surfaces (e.g., bedrails, over-the-bed table) and equipment (e.g., blood pressure cuff) that touch intact skin (Rutala & Weber, 2016).

• Intact skin is an effective barrier against most microorganisms. Because non-critical patient care devices like a blood pressure cuff will only contact intact skin, these items do not need to be sterilized or extensively disinfected (Rutala, 2016). There is no documentation of infectious disease transmission from a non-critical patient care device/patient care equipment (Rutala, 2016). However, these devices and equipment can contaminate the hands of healthcare personnel and subsequently cause person-to-person contamination, so cleaning these items is important.
• Process non-critical patient-care devices using a disinfectant and concentration of germicide.
• Disinfect non-critical medical devices (e.g., blood pressure cuff) with an EPA-registered hospital disinfectant using the label’s safety precautions and directions. By law, all applicable label instructions on EPA-registered products must be followed.
• Non-critical patient-care devices are disinfected regularly, such as after use on each patient or once daily, and when visibly soiled.
• If dedicated, disposable devices are not available, disinfect non-critical patient-care equipment after using it on a patient on contact precautions before using it on another patient (Rutala & Weber, 2019).

Do not perform disinfectant fogging for routine purposes in patient-care areas.

The manufacturer should be contacted for questions about disinfectants. A source of information about low-level or intermediate-level disinfectants is the Antimicrobial Program Branch, Environmental Protection Agency (EPA), Selected EPA-Registered Disinfectants (EPA) (703) 308-6411, or online link.

Endoscopes are fragile, expensive, difficult to clean, much used, and susceptible to contamination (Rutala & Weber, 2019). Millions of endoscopic procedures are done yearly, and iatrogenic infections caused by contamination of endoscopes are rare (Calderwood et al., 2018; Rutala & Weber, 2019). However, endoscopes have been linked to more infectious outbreaks than any other reusable medical device, and failure to properly clean and disinfect endoscopes is a primary reason these outbreaks happen (Rutala & Weber, 2019). In addition, studies have shown that even cleaned and processed endoscopes are often contaminated (Goyal et al., 2022).

The recommendations for the disinfection and sterilization of endoscopes listed below are from the CDC (Rutala & Weber, 2019). The American Society for Gastrointestinal Endoscopy, multi- medical societies, and the Society of Gastroenterology has also published guidelines for cleaning endoscopes (Calderwood et al., 2018). Test each flexible endoscope for leaks in each reprocessing cycle to detect damaged endoscopes. Remove any instrument that fails the leak test from clinical use and repair this instrument.

• Clean: Mechanically clean internal and external surfaces, including brushing internal channels and flushing each internal channel with water and a detergent or enzymatic cleaners (leak testing is recommended for endoscopes before immersion).
• Disinfect: Immerse the endoscope in high-level disinfectant (or chemical sterilant) and perfuse (eliminates air pockets and ensures contact of the germicide with the internal channels) disinfectant into all accessible channels, such as the suction/biopsy channel and air/water channel for the recommended time.
• Rinse: Rinse the endoscope and all channels with sterile water, filtered water (commonly used with AERs), or tap water (i.e., high-quality potable water that meets federal clean water standards at the point of use).
• Dry: Rinse the insertion tube and inner channels with alcohol, and dry with forced air after disinfection and before storage.
• Store: Store the endoscope to prevent recontamination and promote drying (e.g., hung vertically).

Store endoscopes in a manner that will protect them from damage or contamination.

• Sterilize or high-level disinfect the water bottle used to provide intraprocedural flush solution and its connecting tube at least once daily. After sterilizing or high-level disinfection of the water bottle, fill it with sterile water.
• Maintain a log for each procedure in which an endoscope has been used and record the following: patient’s name and medical record number, the type of procedure and the date, the name of the endoscopic, the system used to reprocess the endoscope (if more than one system could be used in the reprocessing area), and the serial number or other identifiers of the endoscope that was used.
• Design facilities where endoscopes are used and disinfected to provide healthcare professionals and patients with a safe environment. Use air-exchange equipment (e.g., the ventilation system, out-exhaust ducts) to minimize exposure of all persons to potentially toxic vapors (e.g., glutaraldehyde vapor). Do not exceed the allowable limits of the vapor concentration of the chemical sterilant or high-level disinfectant; these limits are set by the American Conference of Governmental Industrial Hygienists (ACGIH) and OSHA.
• Routinely test the liquid sterilant/high-level disinfectant to ensure minimal effective concentration of the active ingredient. Check the solution daily using the appropriate chemical indicator (e.g., glutaraldehyde chemical indicator to test minimal effective concentration of glutaraldehyde) and document the testing results. Discard the solution if the chemical indicator shows the concentration is less than the minimum effective concentration. Do not use the liquid sterilant/high-level disinfectant beyond the reuse life recommended by the manufacturer (e.g., 14 days for ortho-phthalaldehyde).
• Personnel assigned to reprocess endoscopes should be given device-specific reprocessing instructions to ensure proper cleaning and high-level disinfection or sterilization. Competency testing in these procedures should be done regularly.
• Educate all personnel who use disinfectants and sterilants about the possible biological, chemical, and environmental hazards of performing procedures that require these products.
• The appropriate PPE should be provided to the staff who clean and disinfect endoscopes.
• If using an automated endoscope reprocessor (AER), place the endoscope in the reprocessor, and attach all channel connectors to ensure exposure of all internal surfaces to the high-level disinfectant/chemical sterilant.
• If using an AER, ensure the endoscope can be effectively reprocessed in the AER. Also, ensure any required manual cleaning/disinfecting steps are performed (e.g., the elevator wire channel of a duodenoscope might not be adequately disinfected by most AERs).
• Review the FDA advisories and the scientific literature for reports of deficiencies that can lead to infection, as design flaws and improper operation and practices have compromised the effectiveness of AERs.
• Develop protocols to ensure that users can readily identify an endoscope that has been appropriately processed and is ready for patient use.
• Do not use the carrying case designed to transport clean and reprocessed endoscopes outside the healthcare environment.
• For quality assurance purposes, no recommendation is made about performing microbiologic testing of either endoscope or rinse water.
• If environmental microbiologic testing is conducted, use standard microbiologic techniques.
• If a cluster of endoscopy-related infections occurs, investigate potential transmission routes (e.g., person-to-person, common source) and reservoirs.
• Report outbreaks of endoscope-related infections to persons responsible for institutional infection control, risk management, and the FDA. Notify the local and state health departments, CDC, and manufacturer(s).
• According to this guideline, no recommendation is made regarding reprocessing an endoscope immediately before use if that endoscope has been processed after use.
• Compare the reprocessing instructions provided by the endoscope and the AER’s manufacturer’s instructions and resolve any conflicting recommendations.

Other medical devices in contact with mucous membranes are considered to be semi-critical. They include but are not limited to rectal and vaginal probes, flexible cystoscopes, tonometers, and ultrasound probes used for various procedures. The risk of contracting an infectious disease from one of these devices is minimal but not impossible. Contamination with microorganisms such as cytomegalovirus, human papillomavirus, hepatitis C, herpes simplex, Klebsiella, and Pseudomonas have been found on these devices, even after cleaning and disinfection (Leroy, 2013).

Disinfection strategies vary widely for these semi-critical items/devices. The FDA requests that manufacturers provide at least one validated cleaning and disinfection/sterilization protocol in labeling their devices. The CDC guidelines are listed below; disinfection and sterilization with different hydrogen peroxide or ultraviolet light are also being evaluated for sterilizing these devices.

• Even if probe covers have been used, clean and disinfect semi-critical devices such as rectal probes, vaginal probes, and cryosurgical probes with a product that is not toxic to staff, patients, probes, and retrieved germ cells (if applicable). A high-level disinfectant at the FDA-cleared exposure time should be used.
• Use a probe cover or a condom to reduce microbial contamination when available. Do not use a lower disinfection category or stop following appropriate disinfectant recommendations when using probe covers because these sheaths and condoms can fail.
• After high-level disinfection, rinse all items. Use sterile water, filtered water, or tap water followed by an alcohol rinse for semi-critical equipment that will have contact with mucous membranes of the upper respiratory tract, e.g., the nose, pharynx, and esophagus.
• There is no recommendation to use sterile or filtered water rather than tap water for rinsing semi-critical equipment that contacts the mucous membranes of the rectum (e.g., rectal probes, anoscope) or vagina (e.g., vaginal probes).
• Wipe clean tonometer tips and disinfect them by immersing them for 5-10 minutes in either 5000 ppm chlorine or 70% ethyl alcohol. None of these listed disinfectant products are FDA-cleared high-level disinfectants.

Steam is the preferred method for sterilizing critical medical and surgical instruments not damaged by heat, steam, pressure, or moisture.

• Cool steam or heat-sterilized items before they are handled or used in the operative setting.
• Follow the sterilization times, temperatures, and other operating parameters (e.g., gas concentration, humidity) recommended by the manufacturer(s) of the instruments, the sterilizer, and the container or wrap used that are consistent with government agency and professional organization guidelines.
• Use low-temperature sterilization technologies like ethylene oxide (EtO) or hydrogen peroxide gas plasma to reprocess critical patient-care equipment that is heat or moisture sensitive.
• Completely aerate surgical and medical items that have been sterilized in the EtO sterilizer before using these items.
• The peracetic acid immersion system can sterilize heat-sensitive immersible medical and surgical items.
• The peracetic acid immersion process must be sterilized, for critical items must be used immediately.
• Dry-heat sterilization at 340°F for 60 minutes can be used to sterilize items like powders and oils that can sustain high temperatures.
• Comply with the sterilizer manufacturer’s instructions regarding the sterilizer cycle parameters.
• Narrow-lumen devices are challenging to low-temperature sterilization technologies, and direct contact is necessary for sterilization to be effective. Ensure that the sterilant has direct contact with contaminated surfaces. For example, scopes processed in peracetic acid must be connected to channel irrigators (Rutala & Weber, 2019).

• Packaging materials must be compatible with the sterilization process and have received FDA 510[k] clearance.
• Packaging must be strong enough to resist punctures and tears and to provide a barrier to microorganisms and moisture (Rutala & Weber, 2019).

• Chemical indicators indicate that the item has been exposed to the sterilization process. Chemical indicators should be used with biological indicators. Still, they should not replace them because only a biological indicator consisting of resistant spores can measure the microbial killing power of the sterilization process. Chemical indicators are placed outside each pack to show that the package has been processed through a sterilization cycle, but these indicators do not prove sterilization has been achieved. Preferably, a chemical indicator should also be placed on each pack's inside to verify sterilant penetration. Chemical indicators are usually heat-or chemical-sensitive inks that change color when one or more sterilization parameters are present.
• Biological indicators are the only process indicators that directly monitor the lethality of a given sterilization process. Biological indicators are recognized as the closest to an ideal monitor of the sterilization process because they measure the sterilization process directly by using the most resistant microorganisms (i.e., Bacillus spores) and not by merely testing the physical and chemical conditions necessary for sterilization.
• Use biologic indicators for every load containing implantable and quarantine items, whenever possible, until the biologic indicator is negative.
• Objects other than implantable objects need not be recalled because of a single positive spore test unless the steam sterilizer or the sterilization procedure is defective. A single positive spore test does not necessarily indicate a sterilizer failure. If the test is positive, the sterilizer should immediately be rechallenged for proper use and function. If there is a sterilizer malfunction, the items must be considered nonsterile, and the items from the suspect load(s) should be recalled, when possible, and reprocessed. Suppose the mechanical (e.g., time, temperature, pressure in the steam sterilizer) and chemical (internal and/or external) indicators suggest that the sterilizer was functioning properly. In that case, a single positive spore test probably does not indicate sterilizer malfunction, but the spore test should be repeated immediately. If the spore tests remain positive, the sterilizer should be discontinued until serviced. If patient-care items were used before retrieval, the infection control professional should assess the risk of infection in collaboration with central processing, surgical services, and risk management staff.
• The margin of safety in steam sterilization is sufficiently large enough that minimal infection risk is associated with items in a load that show spore growth, especially if the item was cleaned correctly and the temperature was achieved. No published studies document disease transmission via a non-retrieved surgical instrument following a sterilization cycle with a positive biological indicator.
• Sterilization records (mechanical, chemical, and biological) should comply with standards (e.g., Joint Commission for the Accreditation of Healthcare Facilities requests three years) and state and federal regulations (Rutala & Weber, 2019).

• Place items correctly and loosely into the sterilizer's basket, shelf, tray, or cart. It will ensure that the penetration of the sterilant is not impeded (Rutala & Weber, 2016).

• The sterile storage area should be well-ventilated and protected against dust, moisture, insects, extreme temperature, and humidity.
• Store sterile items so the packaging is not compromised, e.g., punctured or bent.
• The shelf life of a packaged sterile item depends on many variables: the quality of the wrapper, the storage conditions, the conditions during transport, the amount of handling, and moisture. If event-related storage of sterile items is used, packaged sterile items can be used indefinitely unless the packaging is compromised.
• Before they are used, evaluate packages for loss of integrity, e.g., tears, punctures, and/or wetness.
• If the integrity of the packaging is compromised, repack and reprocess the pack before use.
• If time-related storage of sterile items is used, label the pack at the time of sterilization with an expiration date. When the date expires, reprocess the pack (Rutala & Weber, 2019).

• Provide comprehensive training for all staff assigned to reprocess semi-critical and critical medical/surgical instruments.
• Compare the reprocessing instructions (e.g., for the appropriate use of endoscope connectors, the capping/non-capping of specific lumens) provided by the instrument and sterilizer manufacturer, and resolve any conflicting recommendations by communicating with both manufacturers.
• Conduct periodic infection control in high-risk reprocessing areas like the gastroenterology clinic and central processing to ensure that reprocessing instructions are current, accurate, and correctly implemented. Document all deviations from policy.
• The quality control program for sterilized items should include the following: a sterilizer maintenance contract with records of service, a system of process monitoring, air-removal testing for pre-vacuum steam sterilizers, visual inspection of packaging materials, and traceability of load contents.
• Record the type of sterilizer and cycle used, the load identification number and contents, the exposure parameters (e.g., time and temperature), the operator’s name or initials, and the mechanical, chemical, and biological monitoring results.
• Retain sterilization records for a time that complies with standards, statute limitations, and state and federal regulations.
• Periodically review sterilization policies and procedures.
• Preventive sterilizer maintenance should be done by qualified personnel, and the manufacturer’s instructions should guide it (Rutala & Weber, 2019).

Flash sterilization is a modification of conventional steam sterilization in which the flashed item is placed in an open tray or a specially designed, covered, rigid container to allow for rapid steam penetration (Rutala & Weber, 2019).

Flash sterilization is acceptable for processing cleaned patient-care items that cannot be packaged, sterilized, and stored before use. It is also used when there is insufficient time to sterilize an object using the preferred package method. Still, flash sterilization should not be used for convenience, as an alternative to purchasing additional instrument sets, or to save time. Because of the potential for severe infections, flash sterilization is not recommended for implantable devices (i.e., devices placed into a surgically or naturally formed human body cavity). However, flash sterilization may be unavoidable for devices like orthopedic screws and plates. Suppose flash sterilization of an implantable device is unavoidable. In that case, recordkeeping (i.e., load identification, patient’s name/hospital identifier, and biological indicator result) is essential for epidemiological tracking (e.g., of surgical site infection, tracing results of biological indicators to patients who received the item to document sterility), and to assess the reliability of the sterilization process.

The time and temperature used for flash sterilization vary, depending on the type of sterilizer and the type of item, i.e., porous vs. non-porous items. Example: A non-porous item like a metal instrument with no lumens would be flash sterilized at 132°C/270°F for 3 minutes.

Steam sterilization – sterilization by moist heat under pressure - is the most widely used and dependable form (Rutala & Weber, 2019). Moist heat destroys microorganisms through the irreversible coagulation and denaturation of enzymes and structural proteins. The process is nontoxic, inexpensive, rapidly microbicidal, sporicidal, and rapidly heats and penetrates fabrics (Rutala & Weber, 2019).

The basic principle of steam sterilization in an autoclave is to expose each item to direct steam contact at the required temperature and pressure for the specified time; the four parameters of steam sterilization are steam, pressure, temperature, and time. The two common steam-sterilizing temperatures are 121°C (250°F) and 132°C (270°F). These temperatures (and other high temperatures) must be maintained for the minimal time to kill microorganisms. Recognized minimum exposure periods for sterilization of wrapped healthcare supplies are 30 minutes at 121°C (250°F) in a gravity displacement sterilizer or 4 minutes at 132°C (270°F) in a pre-vacuum sterilizer.

Steam sterilization should be used whenever possible on all critical and semi-critical heat and moisture-resistant items, even when not essential for preventing pathogen transmission. Steam sterilizers also are used in healthcare facilities to decontaminate microbiological waste and sharps containers.

The Joint Commission (TJC) has recommendations for the immediate use of steam sterilization (IUSS). (TJC, 2017).

• Review the equipment manufacturer’s instructions to determine if IUSS is appropriate for a device or instrument.
• Circumstances in which IUSS is an appropriate technique are:
  • When a specific instrument is needed for an emergency procedure
  • When a non-replaceable instrument has been contaminated but needs to be used immediately
  • When an item is dropped on the floor but is needed immediately
• Using IUSS does not mean the proper cleaning and transport steps can be omitted.
• Items suitable for IUSS must be processed in approved/validated containers suitable for IUSS.
• IUSS should not be used for convenience or due to limited instruments or equipment needed for the number of cases/procedures performed.
• Evaluate the IUSS process in all locations where it is being performed.

The FDA considers hospitals or third-party reprocessors to be manufacturers and regulated similarly. Therefore, a reused single-use device will have to comply with the same regulatory requirements of the device when it was originally manufactured (Rutala & Weber, 2019).

Reprocessing is a validated set of processes used to render a medical device, which has been previously used or contaminated, fit for subsequent single use. These processes are designed to remove soil and contaminants by cleaning and inactivating microorganisms by disinfection or sterilization. Reprocessing reusable devices should follow this three-step process (FDA, 2015).

1. Point-of-Use Processing: Reprocessing begins with processing at the point of use (i.e., proximity to the point of use of the device). It involves prompt, initial cleaning steps and/or measures to prevent the drying of soil and contaminants in and on the device.
2. Thorough Cleaning: The device should be thoroughly cleaned after the point-of-use processing. Generally, thorough cleaning is done in a dedicated cleaning area. Devices that will likely not become contaminated with pathogens during use may not require disinfection and may be suitable for use only after cleaning.
3. Disinfection or Sterilization: Depending on the device's intended use, the device should be disinfected or sterilized and routed back into use.

Disinfectants used in healthcare facilities can be contaminated with disease-causing microorganisms, and hospital-acquired infections caused by contaminated disinfectants have been documented (Häfliger et al., 2020). These measures should be used to reduce the occurrence of contaminated disinfectants (Rutala & Weber, 2019):

• Prepare the disinfectant correctly. Some should not be diluted, and those that can be/should be diluted should be prepared using the manufacturer’s instructions.
• Prevent extrinsic contamination of germicides, e.g., container contamination, contaminated water used to dilute the product, or surface contamination of the healthcare environment where the germicides are prepared or used.
• The instructions on the disinfectant labels regarding shelf life, storage, dilution, proper use, disposal, and material compatibility must be followed.
• The user is responsible for any harm caused by off-label use.

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are common nosocomial infections. HAP is the most common nosocomial infection (Klompas et al., 2022a) and is a significant cause of morbidity and mortality (Ko et al., 2021; Modi & Kovacs, 2020). HAP is defined as new pneumonia that begins > 48 hours after admission in non-intubated patients (Modi & Kovacs, 2020). VAP is new pneumonia that begins > 48 hours after endotracheal intubation (Modi & Kovacs, 2020).

Mechanical ventilation is the most important risk factor for HAP (Klompas, 2021). Other risk factors include the following (Kim et al., 2022b; Klompas, 2021):

• Anemia
• Aspiration
• Chest surgery or abdominal surgery
• Chronic lung disease, e.g., asthma, COPD
• Chronic renal failure
• CNS depression
• Drugs that increase gastric pH
• Frequent ventilator circuit changes
• Glucocorticoids
• ICU admission
• Intracranial pressure monitoring
• Malnutrition
• Extensive trauma
• Muscle relaxers
• Paralysis
• Suctioning
• Opioid use
• Tube feeding
• Older age (> 70)

Measures that may help prevent aspiration are listed below (Klompas, 2021; Neill & Dean, 2019; AACCN, 2016).

• Maintain head-of-bed elevation
• Avoid intubation if possible
• Minimize the use of sedatives
• Oral hygiene
• Proper patient positioning during feeding
• Maintain and improve the patient’s physical condition
• Maintaining the ventilator circuit
• Minimize secretion pooling that is above the endotracheal tube cuff
• Combining core preventive measures into a care bundle

Legionella is a bacterium that causes the pulmonary infection of Legionnaire’s disease (CDC, 2021g). Legionella is primarily transmitted by inhaling aerosolized water containing the bacteria (CDC, 2021g). Legionella can be transmitted by aspirating drinking water (uncommon). Although Legionella is not generally considered contagious (CDC, 2021g; OSHA, ND), one episode of possible person-to-person transmission of Legionnaires’ disease has been reported (CDC, 2021g).

Legionellosis outbreaks in workplaces are commonly caused by Legionella growth in poorly maintained artificial water systems (CDC, ND). Examples of sources of Legionella-contaminated water systems that can cause Legionnaire’s disease are listed below (CDC, 2021g; OSHA, ND).

• Cooling towers, evaporative condensers, and fluid coolers using evaporation to remove heat
• Potable water systems and domestic hot water systems
• Humidifiers, misters, foggers, and decorative or display fountains can create a water spray
• Spas, whirlpools, and hot tubs
• Cooling misters, produce misters, and evaporative coolers
• Industrial processes creating aerosolized water
• A Legionellosis outbreak also can occur when aerosolized Legionella is disseminated throughout a workplace in an air handling system from an external or internal contaminated source

Standard Precautions are sufficient infection control techniques when caring for a patient with Legionnaires’ disease (Siegel et al., 2007).

Healthy people do not have a high risk of developing Legionnaire’s disease, and the infection rate after exposure is <5% (CDC, 2021g; OSHA, ND). However, Legionnaire’s disease can be quite severe, and the fatality rate has been reported to be 10% and 25% if the disease is contracted in a hospital (CDC, 2021g).  Factors that increase the risk of developing Legionnaires’ disease include (CDC, 2021g):

• Age ≥ 50 years
• Chronic lung disease
• Chronic illnesses such as diabetes, hepatic failure, or renal failure
• Cigarette smoking (current or past)
• A compromised immune system caused by a disease or a medication
• Exposure to hot tubs
• Heavy drinking
• Systemic malignancy
• Travel outside the home (staying in hotels)
• Recent care at a healthcare facility

Testing for Legionnaires’ disease should be done if (CDC, 2021g):

• The patient has failed outpatient antibiotic treatment for community-acquired pneumonia.
• The patient has severe pneumonia, particularly if they require intensive care.
• The patient is immunocompromised and has pneumonia.
• The patient has pneumonia, and they have traveled away from home for an overnight stay (contaminated water supplies often cause Legionella outbreaks in apartment buildings, hotels, and hospitals). Legionnaires’ disease was first identified and named when an outbreak occurred in a hotel in Philadelphia in 1976; the hotel’s air condition system was contaminated with Legionella.
• The patient has pneumonia, and there is a Legionnaires disease outbreak.
• The patient is at risk for Legionnaires’ disease with healthcare-associated pneumonia (pneumonia with onset > 48 hours after admission).
• The patient had an overnight stay in a hospital within 14 days of the onset of symptoms.
• There is an epidemiological link to a setting in which there is a confirmed case of Legionella or in which there has been at least one laboratory-confirmed case of Legionnaire’s disease.
• Other patients in the healthcare facility have, in the past 12 months, been diagnosed with Legionnaires’ disease.
• There is a positive environmental test for Legionella.
• There are changes in water quality that may lead to Legionella growth.

Clinical laboratory testing: Periodically review the availability and clinicians’ use of laboratory diagnostic tests for Legionnaires’ disease. If clinicians do not routinely use the tests on patients diagnosed with or suspected of pneumonia, implement measures to enhance clinicians’ use of the tests.

Water Management for the Prevention of Legionella Contamination:

A water management program identifies conditions that may cause Legionella contamination and intervenes to minimize the growth and spread of Legionella and other waterborne pathogens in building water systems (CDC, 2021g). Seven key activities should be performed in a Legionella water management program (CDC, 2021g):

• Establish a water management program team.
• Describe the building’s water systems using flow diagrams and a written description.
• Identify areas where Legionella could grow and spread.
• Decide where control measures should be applied and how to monitor them.
• Establish ways to intervene when control limits are not met.
• Ensure the program runs as designed (verification) and is effective (validation).
• Document and communicate all the activities.

An effective water management system should (CDC, 2021g):

• Maintain water temperatures outside the ideal range for Legionella growth (77–113°F).
• Prevent water stagnation.
• Ensure adequate disinfection.
• Maintain plumbing, equipment, and fixtures to prevent sediment, scale, corrosion, and biofilm, providing habitat and nutrients for Legionella.

Routine water sampling to detect Legionella may be appropriate (CDC, 2021g). “The water management program team should regularly monitor water quality parameters, such as disinfectant and temperature levels. By monitoring these parameters, the team can ensure that building water systems are operating to minimize hazardous conditions that could encourage Legionella and other waterborne pathogens to grow. However, it is up to the team to determine how to validate the program's efficacy, based on the environmental assessment and data supporting the overall performance of the water management program” (CDC< 2021h)

Transplant units: In facilities with hematopoietic stem-cell- or solid-organ transplantation programs, periodic culturing for Legionellae in water samples from the transplant unit(s) can be performed as part of a comprehensive strategy to prevent Legionnaires’ disease in transplant recipients.

No recommendation can be made about the optimal methods (i.e., frequency, number of sites) for environmental surveillance cultures in transplant units.

Maintain a high index of suspicion for Legionellosis in transplant patients with healthcare-associated pneumonia even when environmental surveillance cultures do not yield Legionella.

If Legionella spp. is detected in the water of a transplant, remove faucet aerators in areas for severely immunocompromised patients.

Transplant units/positive cultures: If Legionella is detected in the potable water supply of a transplant unit, and until Legionella are no longer detected by culture:

• Decontaminate the water supply.
• Restrict severely immunocompromised patients from taking showers.
• Use water not contaminated with Legionella for patients’ sponge baths.
• Provide hematopoietic stem cell patients sterile water for tooth brushing, drinking, and flushing nasogastric tubes.
• Do not use water from faucets with Legionella-contaminated water in patients’ rooms to avoid creating infectious aerosols.

Healthcare facilities that do not house or treat severely immunocompromised patients (e.g., hematopoietic stem cell transplant or solid-organ transplant recipients):

• If a case of laboratory-confirmed health-care-associated Legionnaires’ disease is identified, or when two or more cases of laboratory-confirmed, possible health-care-associated Legionnaires' disease occur within six months of each other:
  • Contact the local or state health department or the CDC if the disease is reportable in the state or if assistance is needed.
  • Conduct an epidemiologic investigation by reviewing microbiologic, serologic, and postmortem data to identify previous cases.
  • Begin intensive prospective surveillance for additional cases of healthcare-associated Legionnaire’s disease.
• If there is no evidence of continued nosocomial transmissions, continue the intensive prospective surveillance for cases for >2 months after the surveillance has begun.
• If evidence of continued transmission exists:
  • Conduct an environmental investigation to determine the source(s) of Legionella by collecting water samples from potential sources of aerosolized water and saving and subtyping isolates of Legionella obtained from patients and the environment.
  • If a source is not identified, continue surveillance for new cases for >2 months. Depending on the scope of the outbreak, decide to either defer decontamination pending identification of the source(s) of Legionella or proceed with decontamination of the hospital's water distribution system, with particular attention to the specific hospital areas involved in the outbreak.
  • If a source of infection is identified, promptly decontaminate the source.

Pertussis is caused by the Bordetella pertussis (B. pertussis) bacterium. The B. pertussis bacterium is transmitted by depositing infected nasal, oral, or respiratory secretions on a host’s mucous membranes. The B. pertussis bacterium is highly contagious; secondary attack rates are > 80% in susceptible household contacts. People who are particularly vulnerable to becoming infected with B. pertussis and developing severe symptoms are:

1. Infants < 12 months of age,
2. women in the third trimester of pregnancy, and
3. people who have airway disease or who are immunocompromised (CDC, 2022q).

Transmission in healthcare facilities happens when there is close, face-to-face, unprotected (unmasked) contact with an infected person, e.g., an unmasked healthcare worker bathing or feeding a patient, administering a bronchodilator, or doing/assisting with intubation.

The incubation period of pertussis is typically 5 to 10 days, but symptoms may begin as late as three weeks after exposure. Patients develop a mild cough, low-grade fever, and a runny nose (catarrhal stage), followed by the paroxysmal stage, lasting 1-10 weeks, characterized by episodes of rapid coughing – the whoop of whooping cough. Patients begin to recover, and the course of the disease is typically 9 to 13 weeks. Communicability starts at the onset of the catarrhal stage and extends into the paroxysmal stage up to 3 weeks after the onset of paroxysms  (CDC, 2022q).

Use Standard Precautions and Droplet Precautions when caring for someone who has or is suspected of having pertussis. Droplet precautions should be used for five days after the initiation of effective treatment; after that time, the patient is no longer contagious (Siegel et al., 2007). Preferably the patient should be in a single room, but cohorting is acceptable (Siegel et al., 2007). Single-patient rooms are preferred. Post-exposure chemoprophylaxis for household contacts and healthcare workers with prolonged exposure to respiratory secretions is recommended (Siegel et al., 2007).

The CDC recommendations for preventing the transmission of B. pertussis in healthcare facilities include:

• Rapid diagnosis and treatment
• Vaccinate healthcare workers
• Administer post-exposure prophylaxis to exposed persons
• Exclude potentially infectious healthcare workers from the facility

Diagnosis of pertussis is made based on clinical history and laboratory testing. Although cultures are considered the gold standard for diagnosing pertussis, polymerase chain reaction (PCR) provides sensitive results more rapidly.

A healthcare worker vaccinated against pertussis may become infected and develop the disease. Post-exposure prophylaxis with azithromycin, clarithromycin, or erythromycin is recommended. Trimethoprim-sulfamethoxazole is an alternative (CDC, 2022q).

For asymptomatic healthcare personnel, regardless of vaccination status, who have exposure to pertussis and are likely to interact with persons at increased risk for severe pertussis: if these people are not receiving postexposure prophylaxis, restrict from contact (e.g., furlough, duty restriction, or reassignment) with patients and other persons at increased risk for severe pertussis for 21 days after the last exposure.

1. For asymptomatic healthcare personnel, regardless of vaccination status, who are exposed: administer postexposure prophylaxis or implement daily monitoring for 21 days after the last exposure.
2. For asymptomatic healthcare personnel, regardless of vaccination status, with exposure to pertussis and who have preexisting health conditions that may be exacerbated by a pertussis infection: administer postexposure prophylaxis.
3. Symptomatic healthcare personnel with known or suspected pertussis should be excluded from working from 21 days from the onset of the cough or until five days after the start of effective antimicrobial therapy.

Asymptomatic healthcare personnel exposed to pertussis who receive postexposure prophylaxis do not need work restrictions (CDC, 2022q).

Aspergillus is a fungus that is the cause of pulmonary aspergillosis. Aspergillus is ubiquitous in the environment and is transmitted to human hosts by inhalation of infected conidia (CDC, 2022h). Hospital-acquired cases have been reported, sometimes related to construction dust exposure and contaminated medical equipment. The incubation period for aspergillosis is unclear (CDC, 2022h).

Infection with Aspergillus can cause a localized pulmonary infection, especially in patients with pulmonary disease, and immunocompromised people can develop an invasive pulmonary infection. The infection can spread to other organs like the bones, brain, and skin (CDC, 2022h).  People who are at risk for a severe, invasive Aspergillus infection include (but are not limited to) those who have:

• Acquired immunodeficiencies
• Allogeneic hematopoietic stem cell transplant
• Prolonged neutropenia
• Solid organ transplant (SOT)
• Inherited or acquired immunodeficiencies
• The use of corticosteroids (Patterson et al., 2016)

Aspergillosis is diagnosed by culturing and histopathologic/cytologic examination of fluid and tissue samples (Patterson et al., 2016). Treatment will depend on the patient’s co-morbidities and the type of infection, i.e., localized or invasive.

Standard Precautions are sufficient for infection control (Siegel et al., 2007) unless the patient has a massive soft tissue Aspergillus infection that is copiously draining and requires repeated irrigation; in that situation, use Airborne and Contact Precautions, as well (Siegel et al., 2007).

Hospitalized allogeneic hematopoietic stem cell transplant patients and other patients who are highly immunocompromised should be placed in a protective environment. One should reduce the patient’s exposure to dust and limit exposure to cut flowers or plants (Patterson et al., 2016).

“Leukemia and transplant centers should perform regular surveillance of cases of invasive mold infection. An increase in incidence over baseline or invasive mold infections in patients not at high risk for such infections should prompt evaluation for a hospital source” (Patterson et al., 2016).

The CDC’s recommendations for a protective environment (PE) are listed below (CDC, 2015a).

1. Allogeneic hematopoietic stem cell transplant patients only: Maintain an in-room protective environment except for required diagnostic or therapeutic procedures that cannot be performed in the room. Respiratory protection, such as an N95 respirator, for the patient when leaving the protective environment when there is ongoing construction.
2. Infection control procedures/techniques.
   1. Hand hygiene before and after patient contact.
   2. A gown, gloves, and mask are NOT required for healthcare workers or visitors for a routine entry into the room.
   3. Healthcare workers and visitors should wear a gown, gloves, and a mask as per Standard Precautions when indicated for suspected or proven infections.
3. Engineering
   1. Central or point-of-use high-efficiency particulate air (HEPA, 99.97% efficiency) filters capable of removing particles 0.3 μm in diameter to supply (incoming) air.
   2. Well-sealed rooms.
      1. Proper construction of windows, doors, and intake and exhaust ports.
      2. Ceilings: smooth, free of fissures, open joints, and crevices.
      3. Walls sealed above and below the ceiling.
      4. If leakage is detected, locate the source and make necessary repairs.
   3. Ventilation to maintain ≥12 air changes per hour.
   4. Directed air flow: air supply and exhaust grills are located so that clean, filtered air enters from one side of the room, flows across the patient’s bed, and exits on the opposite side of the room.
   5. Positive room air pressure in relation to the corridor.
      1. Pressure differential of >2.5 Pa [0.01” water gauge].
   6. Monitor and document results of airflow patterns daily using visual methods (e.g., flutter strips, smoke tubes) or a handheld pressure gauge.
   7. A self-closing door on all room exits.
   8. Maintain backup ventilation equipment (e.g., portable units for fans or filters) for emergency provision of ventilation requirements for PE areas and take immediate steps to restore the fixed ventilation system.
   9. For patients who require Airborne Infection Isolation, use an anteroom to ensure proper air balance relationships and provide independent exhaust of contaminated air to the outside or place a HEPA filter in the exhaust duct. If an anteroom is unavailable, place a patient in an AIIR and use portable ventilation units and industrial-grade HEPA filters to enhance the filtration of spores.

Surface Cleaning and Disinfection:

• Daily wet-dusting of horizontal surfaces using cloths moistened with EPA-registered hospital disinfectant/detergent
• Avoid dusting methods that disperse dust
• No carpeting in patient rooms or hallways
• No upholstered furniture and furnishings

Other:

• No flowers (fresh or dried) or potted plants in rooms
• Use a vacuum cleaner equipped with HEPA filters when vacuum cleaning is necessary

Adenoviruses, parainfluenza virus, and respiratory syncytial virus (RSV) are common causes of infections like the common cold, conjunctivitis, gastroenteritis, and pneumonia (Clark et al., 2022; CDC, 2020k; CDC, 2019e; Crowe, 2022). Infections with these viruses can be mild and self-limiting. Still, they can also cause a serious illness, particularly in someone who is immunocompromised, in the elderly, the very young, or in people with certain diseases/medical conditions (Clark et al., 2022; CDC, 2020h; CDC, 2019e).

Adenovirus infections can be especially harmful to people with COPD, HIV, an immunocompromised immune system, and those who have had cardiac surgery or a stem cell transplant (Clark et al., 2022).

Older adults and people with compromised immune systems are susceptible to a severe parainfluenza virus infection (CDC, 2019e).

Infants, children, and adults with certain diseases/medical conditions or in certain age groups are more likely to develop a severe RSV infection and include (CDC, 2019e):

• Premature infants
• Infants < 6 months of age
• Children < 2 years of age who have chronic lung disease or congenital heart disease
• Children with suppressed immune systems
• Children who have neuromuscular disorders
• Children who have a neuromuscular disorder that causes difficulty swallowing or clearing of mucus secretions
• Adults > 65 years of age
• Adults who have chronic heart or lung disease
• Immunocompromised adults

Adenoviruses are transmitted by direct contact with a fomite or an infected person and by inoculation of mucous membranes by infected respiratory droplets (CDC, 2019b).

Human parainfluenza viruses are transmitted directly with infected droplets or when an infected person breathes, coughs, or sneezes, spreading infected droplets. The human parainfluenza viruses may remain infectious in airborne droplets for over an hour and on surfaces for a few hours, depending on environmental conditions (CDC, 2019e).

The respiratory syncytial virus is transmitted by infected secretions of the eyes and nose (CDC, 2020k).

Influenza infections are very common, and every year in the United States, 5% to 20% of the population gets an influenza infection (CDC, 2021l). For most people, influenza infection is mild and self-limiting. Still, influenza can be severe and occasionally fatal for the elderly, young people, or certain diseases/medical conditions (CDC, 2021j). From 2010 to 2020, there were 12,000 to 52,000 deaths from the flu every year.

Influenza is primarily transmitted by contact with large, infected respiratory droplets that are expelled when an infected person coughs or sneezes (CDC, 2021l). The droplets can inoculate mucous membranes after hand contact with an infected fomite (CDC, 2021l). Because the infected droplets do not remain airborne for long or travel a long distance (≤ 6 feet), direct inoculation requires very close contact with an infected person (CDC, 2021l). All respiratory secretions and bodily fluids of someone infected with influenza should be considered potentially infectious (CDC, 2021l), as direct contact with infected respiratory droplets causes influenza transmission.

Factors that increase the risk of serious complications for the flu include but are not limited to (CDC, 2021j)

• Age < 2 years, > 65 years
• Asthma
• COPD
• Diabetes mellitus
• Heart disease
• Kidney disease
• Liver disease
• Non-Hispanic Black persons, Hispanic or Latino persons, and American Indian or Alaska Native persons
• Pregnant women 

The CDC’s recommendations for preventing the seasonal flu from occurring in patients and staff of healthcare facilities are discussed below. A healthcare facility is defined as including, but not limited to “. . . acute-care hospitals; long-term care facilities, such as nursing homes and skilled nursing facilities; physicians’ offices; urgent-care centers, outpatient clinics; and home healthcare” (CDC, 2021l). These recommendations are available online.

1. Staff educationThe administration of the healthcare facility should provide all healthcare workers with education and training on preventing the transmission of infectious diseases, specifically:
   1. Signs and symptoms of influenza.
   2. Risk factors for complications.
   3. Diseases/medical conditions that increase the staff’s risk of contracting influenza.
   4. When and to whom the staff should report their signs and symptoms of influenza.
   5. Proper use of PPE and infection control precautions (handwashing, Respiratory Hygiene/Cough Etiquette).
   6. Engineering controls that are used to prevent transmission and reduce exposure.
2. Promote the use of and administer seasonal influenza vaccine. Vaccination “. . . is the most important measure to prevent seasonal influenza infection” (CDC, 2021l).
3. Minimize potential exposures
   1. Instruct patients and persons accompanying them to a healthcare facility to inform providers upon arrival if they have respiratory infection symptoms.
   2. Reduce the number of elective visits by patients who have confirmed or suspected influenza, especially if the symptoms are mild and the patient is not at risk for complications. Consider online or telephone consultation.
   3. Provide handwashing equipment/facilities, masks, and information on how and when to use these infection control measures. Consider setting up a triage/screening area.
4. Monitor and manage ill healthcare personnel
   1. Healthcare workers who develop signs and symptoms of respiratory infection should not report to work. If they are at work, they should stop doing patient care, don a face mask, and notify the supervisor.
   2. Healthcare workers should not work until at least 24 hours after they no longer have a fever without using an antipyretic. Anyone with ongoing respiratory symptoms should be evaluated by occupational health to determine the appropriateness of contact with patients. In addition, these staff members should be considered for temporary reassignment or exclusion from work for seven days from the onset of symptoms or until the non-cough symptoms have resolved, whichever is longer.
   3. A healthcare worker with acute respiratory signs and symptoms who is afebrile may still have an influenza infection. That worker should be evaluated to determine the appropriateness of contact with patients.
   4. A healthcare worker suspected of having influenza may benefit from antiviral treatment.
   5. Respiratory Hygiene/Cough Etiquette, hand washing, and mask use should be reinforced and re-emphasized.
   6. In most cases, decisions about work restrictions and assignments for personnel with respiratory illness should be guided by clinical signs and symptoms rather than by laboratory testing for influenza because laboratory testing may result in delays in diagnosis, false negative test results, or both.
5. Adhere to Standard Precautions
6. Adhere to Droplet Precautions
   1. Suppose a patient is suspected of having influenza or it is confirmed that they have influenza. In that case, Droplet Precautions should be used for seven days after illness onset or until 24 hours after the resolution of fever and respiratory symptoms, whichever is longer. In some cases, facilities may choose Droplet precautions for a longer period, based on clinical judgment, e.g., young children or severely immunocompromised patients, who may shed influenza virus for longer periods.
   2. Place patients with suspected or confirmed influenza in a private room or area. If this is not possible, consult an infection control specialist to determine if cohorting is appropriate.
   3. If Droplet Precautions are in place, the patient should wear a mask when transported outside the room. Anyone in close contact with the patient, like a radiology technician, should be informed of the situation beforehand.
7. Use caution when performing aerosol-generating procedures
   1. An aerosol-generating procedure should only be done if it can’t be postponed.
   2. Limit the number of staff present during the procedure. Influenza vaccination should be offered to the staff present during the procedure.
   3. Wear an N95 mask or an equivalent, gown, gloves, goggles, and a facemask.
   4. Do the procedure in an AIIR, if possible.
8. Manage visitor access to and movement within the facility
   1. Screen visitors before they enter the facility.
   2. Visitors should be limited to those necessary for the patient’s emotional well-being.
   3. Visitors should use Respiratory Hygiene/Cough Etiquette, hand washing, PPE, and limit the number of surfaces they touch. The facility should provide visitors with instructions on these infection control techniques. Visitors should not be allowed to be present during aerosol-generating procedures.
9. Monitor influenza activity
   1. Healthcare settings should promptly establish mechanisms and policies to alert about increased influenza activity in the community or if an outbreak occurs within the facility. Collecting clinical specimens for viral culture may help inform public health efforts.
10. Environmental Infection Control
    1. Standard cleaning and disinfection procedures are sufficient for influenza virus environmental control. Laundry, food service utensils, and medical waste management should also be performed following standard procedures. These items are not a source of influenza virus transmission when these items are properly managed. Laundry and food service utensils should be cleaned, then sanitized as appropriate. Some medical waste may be designated as regulated or biohazardous waste and require special handling and disposal methods.
11. Engineering Controls
    1. Consider designing and installing engineering controls to reduce or eliminate exposures by shielding healthcare workers and other patients from infected individuals.
12. Administer antiviral treatment and chemoprophylaxis of patients and personnel when appropriate
    1. Use the CDC’s recommendations on the CDC website for the most current recommendations on the use of antiviral agents for treatment and chemoprophylaxis.
13. Healthcare personnel at high risk for complications of influenza

Vaccination and early treatment with antiviral medications are for people with an increased risk for influenza complications. Staff with a high risk for influenza complications should consult with their provider if they develop signs and symptoms.

Hepatitis B: Hepatitis B is highly infectious (Schillie et al., 2018), and it can survive on environmental surfaces and be potentially infectious for seven days (CDC, 2020k). Hepatitis B is primarily transmitted by percutaneous exposure, mucosal exposure, or exposure to non-intact skin (Schillie et al., 2018). Semen and vaginal fluids are infectious for HBV (Schillie et al., 2018). Feces, sputum, sweat, nasopharyngeal secretions, vomitus, and urine are not considered important sources of HBV transmission unless they contain blood (Schillie et al., 2018). The risk of HBV transmission after a percutaneous injury is estimated at 22% to 62% (Shenoy & Weber, 2021). There is no accurate estimate of HBV transmission risk after mucosal exposure (Shenoy & Weber, 2021).

Hepatitis C: Hepatitis C is transmitted by contact with infected blood, is transmitted vertically (mother to child), and can be sexually transmitted. The risk of HCV transmission after occupational percutaneous exposure has been estimated to be 0.2% to 1.9% per exposure (Shenoy & Weber, 2021; Naggie et al., 2017). There is no accurate estimate of the risk of HCV transmission after mucosal exposure (Shenoy & Weber, 2021). However, Egro et al. (2017) noted that the data used by the CDC to develop these numbers were from old sources. Some were from non-US medical centers where universal precautions are not used as they should be, and only needlestick injuries were assessed (Egro et al., 2017). These authors examined 1361 exposures over 13 years and found a seroconversion rate of 0.1% (Egro et al., 2017).

HIV: The primary risk of HIV transmission in healthcare is exposure to contaminated blood, typically by a needlestick injury. The risk of HIV transmission after percutaneous exposure has been reported to be 0.23% (Shenoy & Weber, 2021). The risk of HIV transmission after mucosal exposure is estimated at 0.09% (Shenoy & Weber, 2021). The risk of HIV transmission after non-intact skin exposure is rare (Fauci et al., 2018) and has been estimated to be < 0.1% (Shenoy & Weber, 2021). Transmission of HIV through intact skin has not been documented (Fauci et al., 2018).

Fauci et al. (2018) wrote: “In the United States, a total of 58 documented cases of occupational HIV transmission to health care workers, and 150 possible transmissions have been reported by the CDC. Since 1999, only one confirmed case (a laboratory technician sustaining a needle puncture while working with a live HIV culture in 2008) has been reported.”

However, as with the risk estimations for HCV exposure, these estimates have been criticized as possibly being too high and based on conditions that do not reflect current exposure circumstances and the availability and effectiveness of post-exposure prophylaxis (Nwaiwu et al., 2017).

Fortunately, the risk of HCV and HIV transmission and infection is very low, and although HBV is highly infectious, hepatitis B vaccination prevents infection after exposure (Schillie et al., 2018).

Any actual, possible, or potential occupational exposure to HBV, HCV, or HIV should be reported to the appropriate in-house person or department (e.g., supervisor, employee health) immediately or as soon as possible. Do not decide that exposure is/is not a risk for HBV, HCV, or HIV transmission. The decision is the responsibility of the person/department that evaluates risks and prescribes treatment. In several investigations of nosocomial HBV outbreaks, most infected healthcare professionals could not recall an overt percutaneous injury. Although in some studies, up to one-third of the infected persons remembered caring for a hepatitis B surface antigen-positive patient. However, HBV and HCV can survive on environmental surfaces for many hours and days (Shenoy & Weber, 2021). Treatment of exposures should focus on wound care, evaluation of the risk, and post-exposure drug prophylaxis (Schillie et al., 2013):

• Wound care: The basics of wound care are the same for exposure to HBV, HCV, or HIV (Shenoy & Weber, 2021). Wash the wound with soap and water, and flush the eyes and mucous membranes with water. Antiseptics have virucidal action, which may be helpful (Shenoy & Weber, 2021). Do not squeeze a wound to express blood, and do not flush a wound with bleach (Shenoy & Weber, 2021).
• Hepatitis B: The source should be tested for HBsAg, HBsAb, and HBcAb (National Clinician Consultation Center, 2021). A healthcare worker who has confirmed HBV exposure and is not immune should be vaccinated and/or receive hepatitis immune globulin (Weber, 2020). The need for post-exposure testing and drug prophylaxis after exposure to HBV depends on the HBV status of the source patient and the immunization status of the healthcare professional and the source (Weber, 2020). There are a variety of possible circumstances.
  • Example: The exposed healthcare worker has been fully vaccinated against HBV, and that person has a positive response to the vaccination, i.e., a post-vaccination HBSAb titer of ≥ 10 mlU/ml; no treatment or testing is needed. If the exposed person has been fully vaccinated but does not have a positive response, they should be given HBV immunoglobulin and revaccinated (National Clinicians Consultation Center, 2021).
  • The treatment recommendations for all the possible situations regarding when and for whom post-exposure drug prophylaxis should be used after an HBV exposure will not be covered here; they are available at the National Clinicians Consultation Center Website and on the CDC Website.
• Hepatitis C: The source patient should be tested immediately after exposure, preferably within 48 hours (Moorman et al., 2020). The preferred option is to test for HCV RNA; the other option is to test for anti-HCV; if that is positive, test for HCV RNA (Moorman et al., 2020). The exposed person should have anti-HCV testing as soon as possible after the exposure, preferably within 48 hours (Moorman et al., 2020), and an HCV RNA test if the anti-HCV is positive (Moorman et al., 2020). If the source is known or there is an increased risk for HCV acquisition, e.g., injection drug use within the previous four months, or if risk cannot be reliably assessed, initial testing of the source patient should include a nucleic acid test (NAT) for HCV RNA (Moorman et al., 2020).
  • Treatment: Post-exposure prophylaxis with direct-acting antivirals (DAAs) in response to a confirmed exposure to HCV is not recommended (Moorman et al., 2020). If the source is HCV RNA positive, if the source was anti-HCV positive, but HCV RNA testing wasn’t done, or if the source’s HCV status cannot be determined, the exposed person should be tested for the presence of HCV RNA 3 to 6 weeks after the exposure (Moorman et al., 2020). Four to 6 months after exposure, the exposed person should have an anti-HCV test and an HCV RNA test if the anti-HCV test is positive. After that, if the final tests are negative, no further testing is needed unless the exposed person is immunocompromised and/or has liver disease (Moorman et al., 2020). Additional testing can be considered (Moorman et al., 2020). If the exposed person has signs/symptoms of an acute HCV infection at any time, they should be tested. If the source or the exposed person tests positive for HCV RNA, refer for evaluation and treatment (Moorman et al., 2020). There is no HCV vaccine.
• HIV: The source person should be tested if possible (Kuhar et al., 2013). Concerns about HIV-negative sources might be in the so-called window period before seroconversion (i.e., the period between initial HIV infection and the development of detectable HIV antibodies). No such instances of occupational transmission have been detected in the United States. Hence, investigating whether a source patient might be in the window period is unnecessary for determining whether HIV PEP is indicated unless acute retroviral syndrome is clinically suspected (Kuhar et al., 2013).
  • The source should have a rapid test for HIV Ag/Ab or HIV Ab (Kuhar et al., 2013; National Clinician Consultation Center, 2021); the result of a rapid HIV antigen-antibody test is available within 30 minutes. The exposed person should have a rapid test for HIV Ag/Ab or HIV Ab, an HBV test, and an HCV Ab test (National Clinician Consultation Center, 2021). If the source’s HIV test is negative, PEP should be stopped, and no further treatment is needed (Kuhar et al., 2013); National Clinician Consultation Center, 2021). If the source’s HIV test is positive, it should be assumed to be a true positive.
  • Post-exposure prophylaxis is typically not warranted if the HIV status of the source is not known (National Clinician Consultation Center, 2021). The need for PEP should be decided on a case-by-case basis, the epidemiologic likelihood of transmission and risk factors, and the severity of the injury (Kuhar et al., 2013; National Clinician Consultation Center, 2021). In this situation, it is prudent to get a consultation, and PEP can be started while waiting for the consult (National Clinician Consultation Center, 2021).
  • Administration of (PEP) should not be delayed while waiting for the test results (Kuhar et al., 2013; National Clinician Consultation Center, 2021). The best time to start PEP is within hours of exposure (National Clinician Consulting Center, 2021), as the effectiveness of HIV PEP is time-sensitive (National Clinical Consultation Center, 2021). HIV PEP can be administered > 72 hours after exposure, but that is considered the point after which its effectiveness is not known (Kuhar et al., 2013; National Clinician Consultation Center, 2021).
  • Consult an infectious disease expert for advice on giving PEP if the exposed person is pregnant, breastfeeding, or could be resistant to antiretroviral therapy (Kuhar et al., 2013). An infectious disease consult should be obtained if there is/could be a drug-drug interaction between the PEP drugs and the exposed person’s medications (Kuhar et al., 2013).
  • The preferred PEP is a three-drug regimen, and the treatment duration is 28 days (National Clinician Consultation Center, 2021).
    • Truvada™ - a combination of tenofovir 300 mg plus emtricitabine 200 mg, one tablet a day, plus
    • Ralategravir (Isentress®) 400 mg, one tablet twice a day, plus
    • Dolutegravir (Tivicay™), 50 mg, one tablet once a day
  • Other drug regimens can be used for special circumstances, e.g., for someone with significant renal impairment (Kuhar et al., 2013).
  • There is no HIV vaccine. 

HIV Resources:

• By calling 1-888-448-4911 from anywhere in the United States from 9:00 am to 9:00 pm, seven days a week, clinicians can access the National Clinicians Post-Exposure Prophylaxis Hotline (PEPline). The PEPline has trained physicians to give clinicians information, counseling, and treatment recommendations for professionals with needlestick injuries and other serious occupational exposures to bloodborne microorganisms that lead to such serious infections or diseases as HIV or hepatitis.

Other helpful resources are:

•  
• HIV Antiretroviral Pregnancy Registry. Address: Research Park, 1011 Ashes Drive, Wilmington, NC 28405. Telephone: 800-258-4263; fax: 800-800-1052. Email: registry@nc.crl.com.
• Medwatch, FDA (for reporting unusual or severe toxicity to antiretroviral agents) here. Address: U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993. Telephone: 800-332-1088.
• U.S. Department of Health and Human Services. AIDS Info. Address: AIDSinfo, P.O. Box 4780, Rockville, MD 20849-6303. Telephone: 1-800-4448-0440; fax, 1-302-315-2818; TTY, 1-888-480-3739. Email: ContactUs@aidsinfo.nih.gov

Use Standard Precautions, Airborne Precautions (until monkeypox has been confirmed and smallpox has been ruled out), and Contact Precautions until the lesions have crusted over (Siegel et al., 2007).

A confirmed or suspected monkeypox patient should be in a single room; a special air-handling room is unnecessary (CDC, 2022l).

Staff who enter the room should wear a gown, gloves, N95, and eye protection (CDC, 2022l).

Transporting the patient outside the room should be done only if necessary and unavoidable, and the patient should wear a mask outside the room (CDC, 2022l). Any aerosol-generating procedures should be done in an AIIR.

Waste contaminated with monkeypox should be handled like any other potentially infectious material (CDC, 2022l). No specific cleaning/disinfection procedures are required. Dry dusting, sweeping, or vacuuming should be avoided; wet cleaning is preferred.

Visitors should be limited to persons essential to the patient's well-being (CDC, 2022l).

Healthcare personnel and patients in healthcare facilities exposed to monkeypox should be monitored and receive post-exposure management according to current recommendations (CDC, 2022m).

1. Healthcare workers: A healthcare worker who has cared for a monkeypox patient should be alert to the development of symptoms of monkeypox infection, especially within 21 days after the last date of care, and should notify infection control, occupational health, and the health department if symptoms occur.
   1. Healthcare workers who have unprotected exposures (i.e., not wearing PPE) to patients with monkeypox do not need to be excluded from work duty. They should undergo active surveillance for symptoms, including temperature measurement at least twice daily for symptoms 21 days following the exposure. Before reporting for work each day, the healthcare worker should be interviewed regarding evidence of fever or rash.
   2. Healthcare workers who have cared for or otherwise been in direct or indirect contact with monkeypox patients while adhering to recommended infection control precautions may undergo self-monitoring or active monitoring as determined by the health department.
2. Patients/visitors
   1. Those in contact with animals or people confirmed to have monkeypox should be monitored for symptoms for 21 days. Symptoms include a fever ≥100.4°F (38°C), chills, new lymphadenopathy (periauricular, axillary, cervical, or inguinal), and a new skin rash.
   2. Contacts should be instructed to monitor their temperature twice daily. If symptoms develop, contacts should immediately self-isolate and contact the health department for further guidance.
      1. If fever or rash develops, contacts should immediately self-isolate and contact their local or state health department.
      2. If only chills or lymphadenopathy develop, the contact should remain at their residence and self-isolate for 24 hours.
         1. During this time, the individual should monitor their temperature for fever; if a fever or rash develops, the health department should be contacted immediately.
         2. If fever or rash does not develop and chills or lymphadenopathy persist, a clinician should evaluate the contact for a potential cause. Clinicians can consult with their state health departments if monkeypox is suspected.
      3. Contacts who remain asymptomatic can continue routine daily activities (e.g., going to work or school). Contacts should not donate blood, cells, tissue, breast milk, semen, or organs while under symptom surveillance.

Vaccines for monkeypox are available. Antiviral treatment can be used for patients with a high risk for severe disease.