Legionella

This pathogen is the prototypical microbe to highlight transmission of water-borne infections to the immunocompromised host. Legionella is a water-borne gram-negative pathogen associated with symptoms that range from a mild febrile illness to pneumonia with respiratory distress. Healthcare-associated transmission of laboratory-confirmed Legionnaires’ disease, defined as infection in patients hospitalized for 10 days or longer before confirming diagnosis, has been described among HSCT recipients. ^, Transmission occurs through inhalation of aerosolized water particles or exposure to contaminated water. Many published reports note that fountains, showers, water fixtures, and nonaerated faucets have been implicated as the source of outbreaks of water-borne illness. Other organisms with similar transmission routes include P. aeruginosa, Burkholderia cepacia, and Stenotrophomonas maltophilia . Methods to mitigate risk and curtail outbreaks are detailed in the “Water Quality” section later in the text.

Staphylococcus aureus and vancomycin-resistant Enterococci

S. aureus and Enterococci species are ubiquitous in the healthcare environment. The clinical impact of these bacteria includes severe infections in immunocompromised patients, although there remain conflicting data on whether these high-risk populations have increased mortality compared with immunocompetent children.

S. aureus , including methicillin-resistant S. aureus (MRSA), is an important cause of morbidity in pediatric immunocompromised patients. Staphylococcal infections in pediatric oncology and HSCT patients are predominately invasive and catheter associated, with a high rate (18%) of complications, not specifically associated with MRSA. In up to 5% of pediatric solid organ transplant (SOT) recipients in whom S. aureus infections developed, half of the isolates were identified as MRSA. Despite these reported infections, studies are not entirely supportive of the necessity or timing of MRSA screening and decolonization to reduce infections.

The incidence of infections secondary to vancomycin-resistant Enterococcus (VRE) is relatively low among immunocompromised patients and the impact on morbidity and mortality may vary according to the underlying medical or clinical condition. In one registry-based population study, HSCT recipients who experienced VRE bacteremia demonstrated decreased 1-year survival and increased nonrelapsed mortality compared with patients with non-VRE bacteremia, but study findings are limited by the exclusion of known contributing factors, such as GVHD, in the analysis. Among SOT recipients, a meta-analysis reviewing VRE colonization demonstrated that pre- and post-transplant VRE colonization portends a statistically significant risk for VRE infection among transplant recipients.

Accepted infection prevention practices to limit the transmission of multidrug-resistant organisms such as MRSA and VRE include use of PPE (i.e., donning gowns and gloves before caring for a colonized patient). One publication suggests that the routine use of contact isolation to prevent transmission of VRE may not be necessary, although study limitations (exclusion of noninvasive infection, adult population) preclude generalization of these findings to the pediatric population.

S. aureus decolonization, using topical antibiotics to eradicate nasal colonization, is recommended in critically ill patients admitted to the intensive care unit as it decreases the incidence of invasive S. aureus infections during their hospitalization. ^, There are few studies assessing the utility of screening and routine decolonization of transplant and oncology patients except in the case of preoperative decolonization. Case-by-case decision making for the use of mupirocin for decolonization may be warranted. Although the debate continues on the utility of contact isolation to limit transmission of MRSA and VRE, facilities housing immunocompromised patients should closely monitor for increased incidence of disease if contact isolation for MRSA and VRE is not routinely used.

Clostridium difficile

C. difficile is a bacteria that causes infections in patients with prolonged exposure to antibiotics or exposure to the healthcare system, most of whom are immunocompromised patients. C. difficile has been responsible for numerous healthcare-associated outbreaks, even within immunocompetent hosts. The particular strain, toxinotype III, North American pulsed-field type 1, and PCR ribotype 027 (NAP1/027), known to produce large amounts of toxin A and B, has been identified in these outbreaks across the globe. Reduction of antimicrobial use is the predominant modifiable risk factor that decreases the risk for C. difficile infection. An infrastructure that supports infection prevention and antibiotic stewardship to reduce HAIs such as C. difficile is ideal. In addition, appropriate hand hygiene with soap and water before and after contact with a patient is recommended. Some experts support the use of an alcohol-based hand sanitizer in non-outbreak settings. Contact precautions (i.e., PPE of gown and gloves) should be used by HCWs caring for transplant and oncology patients infected with C. difficile . ^,

C. difficile spores may persist within the healthcare environment; optimal cleaning of infected patient rooms using a bleach-containing disinfectant (5000 ppm) is advised. During endemic outbreaks or in hospital units with high rates of healthcare-associated C. difficile , terminal cleaning with a sporicidal agent and preferential use of soap and water for handwashing are recommended. Other modalities for cleaning and disinfection, such as ultraviolet germicidal irradiation and vaporized hydrogen peroxide, have shown promising results, but data are insufficient at this time to make firm conclusions for use in routine or outbreak settings. Compared to MRSA and VRE isolation, there is little debate and some evidence to support the necessity of contact isolation to decrease transmission of C. difficile .

Multidrug-resistant gram-negative organisms

Microorganisms resistant to one or more classes of commercially available antimicrobial agents are described as multidrug-resistant organisms (MDROs). Gram-negative organisms are emerging as epidemiologically important pathogens owing to the high rate of healthcare-associated transmission, the increasing number of outbreaks, and the increased mortality rates associated with invasive infections in children. Risk factors independently associated with developing a severe infection with an MDRO, specifically carbapenem-resistant Klebsiella pneumoniae, include recent organ or stem cell transplantation, prolonged length of hospital stay, and extensive use of antibiotics, all of which are often present in the pediatric immunocompromised population. A carbapenem-resistant Enterobacteriaceae (CRE) infection develops in up to 10% of SOT recipients if they reside in a CRE-endemic area. Preventing the spread of these pathogens has now been listed as an urgent priority by the CDC.

Prevention strategies should incorporate efforts to delay the advent of resistance by promoting judicious broad-spectrum antimicrobial use in highly vulnerable patients. Performing surveillance cultures of the perianal and rectal regions of at-risk patients can identify patients colonized with MDROs and preemptive cohorting or contact isolation may prevent healthcare-associated exposures. Surveillance of CRE or carbapenem-resistant Klebsiella pneumoniae and ongoing implementation of bundled infection prevention practices, including hand hygiene, preemptive use of contact precautions for colonized patients, and multidisciplinary teams to monitor adherence to recommendations are part of a comprehensive program to minimize the impact of MDROs. ^,

Mycobacteria

Nontuberculous mycobacteria are ubiquitous in the environment and outbreaks have been well described in immunocompromised patients. Transmission may occur through contact with soil or contaminated water. Over a 10-year period, investigators at a U.S.-based cancer treatment institution described clinical risk factors associated with rapidly growing mycobacteria infections, typically within 7 days of culture incubation, in patients with cancer. Although few clinical cases occurred (2.9 per 100,000 patient-days), disease in 59% of patients was diagnosed from respiratory specimen cultures and most infections occurred in SOT patients. Continued assessment of air and water quality (see later text) is needed to decrease the burden of particulates or spores in healthcare areas housing immunocompromised patients. Screening HCWs for M. tuberculosis should be based on local prevalence and regulations.

Opportunistic mold

Opportunistic molds (such as Aspergillus ) cause significant morbidity and mortality in immunocompromised patients, although mortality rates are highly variable according to the underlying condition of the affected patient population and the advent of antifungal prophylaxis. Opportunistic molds are associated with dusty or moist environmental conditions, such as those found in construction areas. Contribution of the healthcare environment to an invasive fungal infection of a patient is hampered by the unknown incubation period of Aspergillus and the threshold spore count necessary for infection. Prevention strategies to protect patients against mold infections should include minimization of dust accumulation and dust disturbance.

Viruses

Pediatric patients are at high risk for transmissible viral infections, especially during seasonal outbreaks. The all-cause mortality among pediatric HSCT recipients who were hospitalized with a respiratory viral infection over a 3-year period was as high as 11%, suggesting significant contribution to outcomes after HSCT. Over a similar period and among more than 1000 pediatric SOT patients hospitalized with respiratory viral infections, intestinal/abdominal transplant recipients (38%) were most often affected; however, case fatality within 3 months of infection was lower (4%) than HSCT recipients. Reverse droplet precautions, where all HCWs wear masks before interactions with neutropenic patients during respiratory viral seasons, are used in various institutions, but no available evidence supports this practice. Early identification of immunocompromised hosts with viral infections and implementation of contact and droplet precautions may attenuate healthcare-associated viral transmission. Limiting exposure to ill HCWs and visitors may help with preventing respiratory viral infections. Routine surveillance for community-acquired respiratory viruses in asymptomatic immunocompromised patients is not advised.

Nonrespiratory viruses also affect the pediatric immunocompromised host. Gastrointestinal (GI) viruses may be acquired from the community (e.g., norovirus) or represent reactivation (e.g., adenovirus, cytomegalovirus). Healthcare-associated transmission of norovirus and adenovirus have been reported in patient populations with oncologic disease and recipients of HSCT and solid organs. ^, The presence of GI viruses in immunocompromised patients, regardless of clinical suspicion as to the primary etiology of a diarrheal illness or merely intestinal shedding, should prompt the appropriate isolation precautions to minimize transmission to other vulnerable patients. Although prolonged intestinal shedding is well known to occur in immunocompromised patients, it is unclear whether isolation needs to be extended past resolution of diarrheal symptoms to minimize transmission.

Transmission of viruses, historically known as blood-borne (human immunodeficiency virus, hepatitis B, hepatitis C), have largely been eliminated through national screening programs. Expansion of the screening panel (e.g., inclusion of West Nile Virus) or temporary inclusion of emerging pathogens (Zika virus) further ensures the safety of the blood supply to all patients.

Vaccine-preventable viruses, namely varicella-zoster and measles, can cause virulent infections in immunocompromised patients. Centers with declining community vaccine rates (and likely low herd immunity) may consider restricting incompletely vaccinated children from visiting pediatric transplant units. Sufficient data to support the use of airborne precautions and in tandem N95 masks by vaccinated HCWs to prevent transmission of measles and varicella-zoster viruses do not currently exist. Some have suggested that surgical masks and PPE may be sufficient. However, for consistency among HCWs and to avoid confusion, some facilities may opt to use airborne precautions for all patients being evaluated for or currently being treated for specific viral infections. To comply with airborne precautions and prevent inhalation of infected particles, HCWs should have scheduled fit testing to confirm their ability to use a respirator with N95 or higher filtration.

Policies regarding sick providers

HCWs with highly transmissible infections, such as GI illnesses, acute influenza-like illness, and exposed skin lesions, should be advised to limit direct patient care for transplant or oncology patients. These syndromes may allow for pathogen spread via contact, droplet, or airborne transmission. HCW restriction should last for the duration of the illness or until clearance is obtained from occupational health or according to national published guidelines.

Vaccinations of healthcare workers and close contacts

A general principle of infectious diseases and infection prevention is the use of vaccinations as a protective measure. Immunization of selected groups of immunocompromised patients with inactivated/killed vaccines can provide a measure of protection. Herd immunity of HCWs and family members of immunocompromised hosts maintains the protective environment within and outside of the hospital. Recommended vaccinations for family members, close contacts, and HCWs include hepatitis A, influenza, polio, measles-mumps-rubella, Haemophilus influenzae , varicella, tetanus, diphtheria, and pertussis.

Visitation policies

Visitation recommendations may vary among institutions housing immunocompromised patients. Policies regarding visitation should be made in consultation with a multidisciplinary team, including local pediatric infection prevention, nursing, physician, and ancillary staff. At a minimum, policies should restrict ill individuals unless they are critical to the care of the immunocompromised patient. Some facilities restrict visitation based on age, season, or total number of persons allowed in the patient’s room at any given time and for a specific duration. These restrictions are based, in part, on concerns that asymptomatic visitors may shed and transmit viruses to patients. Visitor restriction should be balanced with the benefits of the emotional well-being of the patient. Visitor screening could be a useful component to visitation and should assess for immunization status, active symptoms, and recent exposure to possible communicable infections.

Animal safety

Animals may be encountered in a healthcare setting. Therapy animals serve a beneficial purpose within a healthcare setting, but this benefit should be balanced with risks of transmission of pathogens from the animal’s fur, mouth, and paws. These pathogens may originate directly from the animal (such as Salmonella , Pasteurella, or Capnocytophaga ) or be acquired as the animal passes through the healthcare facility (such as S. aureus ). Professionally trained animals should be handled according to institutional policies. It may be prudent to restrict access to therapy animals if patients are immunocompromised, although no formal recommendation addresses this particular situation. A published guidance on animals in healthcare settings showed that up to a third of centers with policies on animal-assisted activities excluded therapy animals from immunocompromised patients, although the definition of those patients may vary (e.g., neutropenia, HSCT pre-engraftment, asplenia). At a minimum, excellent hand hygiene before and after touching/encountering the animal is advised. Animals such as birds and reptiles should be restricted from hospital units owing to the high risk of colonization with infectious organisms. Visitation by an individual’s personal pet should be restricted, although end-of-life decisions may be made on a case-by-case basis.

Good bathing practices: Showers and wipes

Personal hygiene is important for prevention of infections from endogenous skin flora. The use of showers has been controversial, as several studies implicate aerosols from showerheads in outbreaks of water-borne pathogens. No formal recommendation against prohibition of showers in immunocompromised patients exist, although shower restrictions may be implemented if there is concern for an outbreak. Experts recommend running showers for up to 10 minutes during routine hospital room cleaning to limit accumulation of stagnant water in showerheads.

Chlorhexidine gluconate (CHG), a commonly used skin antiseptic, is an integral part of catheter insertion and maintenance practices within hospitals. However, data are inconclusive on the use of daily bathing with chlorhexidine-containing products as a means of reducing bloodstream infections in immunocompromised patients. Reported decreases in infections may be largely dependent on decreased blood culture contamination with skin commensals such as coagulase-negative staphylococci, but one multicenter, cluster-randomized study showed statistically significant decreased rates of MDRO (MRSA, VRE) colonization and infection after implementation of CHG bathing with minimal adverse effects in HSCT patients. Despite potential limited utility and reports of mild skin irritation with frequent CHG use and restricted use in premature infants, chlorhexidine remains a safe and effective option for skin cleansing in immunocompromised pediatric patients and could be implemented for critically ill patients or those who are unable to shower. ^,

Toys

Toys are commonly colonized with bacteria, and publications regarding outbreaks within pediatric oncology units have implicated toys. There have been no reports of shared toys as an underlying factor in a mold outbreak; however, contaminated bath toys have been implicated in outbreaks of P. aeruginosa. Encouraging single-use toys or shared toys with nonporous surfaces that can be easily cleaned or washed is recommended. Manufacturer claims about antimicrobial properties of soft toys or hard toy covers may need to be evaluated further. Guidance is published on appropriate cleaning of toys by the CDC.

Food safety

Food safety should always be a priority, especially for immunocompromised patients. Food may be a vehicle for bacterial contamination with E. coli and Salmonella . Immunocompromised patients should avoid raw fruits and vegetables that cannot be effectively washed, peeled, or cooked.

Mask use in patients during ambulation or transportation within hospitals

The issue of whether masks (particularly N95 respirators) should be routinely worn by patients outside hospital or clinic rooms is unresolved. ^, Risk factors for inhaling infectious particles include the presence and nature of construction or demolition, the degree of immunocompromised status, and whether patients are receiving antifungal prophylaxis. In areas with active construction, large crowds, or with critically ill patients, N95 or surgical masks may be worn by the pediatric HSCT and oncology patients. There are no existing guidelines or data showing the benefit of masking in SOT patients. No commercially available masks have been systematically evaluated for prevention of spores and mold inhalation. Use of cloth masks or decorated mesh masks is not advised.

Environmental impact on medical care of immunocompromised patients

The environment contains a variety of opportunistic pathogens that can be responsible for disease transmission in immunocompromised patients, resulting in significant morbidity and mortality. These reservoirs, such as dust and moisture for mold, may be disturbed during manipulation of the environment. In addition, disruptions of engineering systems for maintaining air and water quality may also promote proliferation of opportunistic infections. Such disruptions increase the pathogen load in the air and water and increase risk of acquisition and severity of infection in the immunocompromised host.

Air quality

Air quality is absolutely critical to the safety of patients, even in the absence of accompanying construction. Air handling systems (heating, ventilation, air conditioning [HVAC] system) can be ideal environments for microbial growth because pathogens such as opportunistic fungi can proliferate in areas with air, dust, and water. Advance notice of scheduled HVAC maintenance, particularly if it affects areas occupied by high-risk patients, will allow appropriate measures to be taken to minimize dust and moisture intrusion.

The use of high-efficiency particulate absorption (HEPA) filtration may be desired to improve air quality in areas housing high-risk patients. HEPA filters remove at least 99.97% of particles 0.3 μm or smaller in diameter (as a reference, Aspergillus spores are 2.5 to 3.0 μm in diameter). Although the purpose of HEPA filtration is to reduce fungal spores from the environment, one meta-analysis showed little survival benefit in immunocompromised patients. Despite this, many existing and new facilities choose to invest in HEPA filtration.

Using a protective environment (PE) during hospitalizations could mitigate the acquisition of environmental fungal infections. PEs combine HEPA filtration, high numbers (≥12) of air changes per hour, and positive pressure. Positive pressure refers to the differential between two adjacent spaces (room and hallway), in which air flows away from the area to keep airborne pathogens from entering the airspace of the room. Patients with anticipated prolonged neutropenia, such as HSCT recipients and patients with leukemia, should have priority placement into PEs. The air pressure gradient of all rooms (especially those designed for PEs and for airborne infections) should be monitored and documented periodically, especially if the rooms are occupied by patients.

Measurements of air quality within a given space may take the form of particle counts (size and total quantity) and/or microbiologic sampling for fungal spores. There are no widely accepted thresholds for air sampling.

Routine air sampling for fungal spores is not recommended for several reasons. There is no clear threshold of spore counts that predicts acquisition of fungal infection and the unknown incubation of Aspergillus makes it difficult to attribute fungal infections as healthcare associated, resulting in a lack of standardized protocols for testing (sampling intervals, number of samples per area). In addition, the investment of laboratory resources for microbiologic air testing can be prohibitive. Hence routine microbiologic air sampling is not advised. Individual healthcare facilities may develop their own schedule for airborne particle sampling to assess the performance, maintenance, and cleaning efficiency of airflow systems and dust-control measures. ^,

Because air quality is vital to the health of immunocompromised patients, medical providers should have a working understanding of the various mechanisms at their healthcare facility surrounding air handling. The use and placement of HEPA filters (rooms, hallways, central, portable), location of rooms with positive pressure, and priority placement of HSCT recipients and patients with leukemia into PEs should be appreciated. Periodic rounds (at least annually) with infection prevention providers and facility maintenance personnel would provide reciprocal education regarding logistics of air handling and patient safety.

Construction and renovation

The construction and renovation of healthcare facilities affect air quality control. Clinically significant microorganisms are released into the air when environmental reservoirs (i.e., soil, water, dust, and decaying organic matter) are disturbed and brought into the healthcare environment. Many publications have strongly suggested that construction and renovation activity are independent risk factors for invasive mold infections in heavily immunosuppressed populations. ^, The most commonly reported healthcare-associated invasive mold infection is Aspergillus , and the primary site of infection is the lower respiratory tract.

Dust control measures during construction can minimize aerosolization of fungal particles. To that end, infection prevention professionals should be notified and involved in hospital projects with anticipated dust disturbance. These projects require completion of an infection control risk assessment (ICRA) that calculates the necessary control measures for dust and moisture containment based on the project type and patient risk groups. These control measures may include (but are not limited to) containment barriers (e.g., rigid, dustproof, airtight seals); close monitoring of air quality with possible use of portable HEPA filters and/or air particulate sampling; and relocating or redirecting high-risk patients away from construction. A multidisciplinary team should discuss and implement appropriate measures as determined by the ICRA. Compliance with recommendations should be monitored with regular visits and feedback by infection prevention professionals.

Surveillance for healthcare-associated mold infection is difficult but crucial to outbreak detection, particularly during periods of construction and renovation. The infection prevention professional should work closely with clinicians to identify and mitigate clusters of possible, probable, or proven cases of fungal infections. Although some facilities may use microbiologic air sampling and particle counts during times of construction, this should not replace or supersede clinical surveillance. There may be a role for microbiologic air sampling or particle counts during outbreak investigation if it becomes necessary to localize an area to determine infection prevention interventions.

Furnishings

To prevent dust accumulation and aerosolization, the use of counters and furniture with smooth, nonporous surfaces that can be adequately scrubbed is advised. Carpeting should not be installed within hospital units as they have been implicated in outbreaks of aspergillosis. Patients should be encouraged to minimize and reduce the clutter that can accumulate over a prolonged hospitalization. This would allow environmental services personnel to easily clean the room, as well as minimize dust accumulation that may serve as a reservoir for mold. One possible strategy for facilities to consider is inpatient room rotations for long-stay patients to allow for optimal deep cleaning of their environments.

Care of linens and healthcare worker attire

Reports of pulmonary and cutaneous fungal infections have implicated contaminated hospital linen supplies. The linen supply chain, from the laundry facility to the transport of supplies to the hospital, and the storage of linens, should be monitored. Standards for processing of hospital linens are available from the Healthcare Laundry Accreditation Council and should be followed. A single case of healthcare-associated cutaneous fungal infection should prompt investigation of linen care at the laundry facility and in the hospital. The process of soil removal, pathogen removal, and pathogen inactivation will render the laundry free of vegetative organisms, thus becoming hygienically clean. Outside the operative room, it is not necessary to use sterile linens for immunocompromised patients.

Although the attire of HCWs may be contaminated with pathogenic microorganisms, there are no reports directly linking contaminated HCW attire to outbreaks outside the operative arena. There are cost-saving measures in healthcare facilities that have staff launder their own clothing, and no guidance exists for care of nonoperative HCW attire. At a minimum, attire should be clean and free of noticeable dirt and stains.

Plants

Live flowers or plants and their potting materials may harbor large numbers of fungal spores that can easily become aerosolized. Although exposure to plants and flowers has not conclusively been shown to cause invasive mold infections, most experts recommend that plants and dried/fresh flowers should not be allowed in hospital rooms of neutropenic or immunocompromised patients. ^,

Water quality

Outbreaks attributed to contaminated healthcare-associated water supplies have been reported. The most common pathogens associated with outbreaks include Legionella , nontuberculous mycobacteria, and Pseudomonas , all of which have been identified in municipal drinking water. The infection prevention professional should be knowledgeable of the quality and treatment (filtration, chlorination) of the municipal water before its entry into the hospital water supply.

Water-borne outbreaks occur when pathogen concentrations are increased in the hospital water supply (e.g., introduction of dust or dysregulation of water temperature allowing pathogen growth), or when such water is aerosolized (including open water features such as water walls and decorative water fountains). Measures to reduce bioburden within hospital water systems include scheduled maintenance of faucets and sinks (i.e., cleaning and disinfecting aerators and faucets), insulating recirculation water pipe loops, and evaluating for backflow and cross-connections in high-risk units. Recommendations are to store hot water above 140°F (60°C) and circulate with a minimum return temperature of 124°F (51°C), whereas cold water temperatures should be below 68°F (20°C). Annual inspection of thermostats, water pressurization, and climate control and fire protection systems will ensure that waterways remain adequately functional.

Complete eradication of pathogens and associated biofilms from hospital tap water and the plumbing infrastructure is not realistic given the environmental persistence of many of these microbes. Facilities may add filters to ice machines, showerheads, and/or sinks that are used or in proximity to immunocompromised patients. Ice machines should be dismantled and cleaned according to the manufacturer’s recommendation. Various water disinfectant systems are available for use. Flushing chlorinated water through the water system intermittently may be useful; however, there are no standard recommendations for the use of chlorine dioxide, heavy metal ions, such as copper and monochloramine, ozone, or ultraviolet light for water sterilization. It should be noted that use of carbon filters might remove chlorine from water supply and subsequently lead to increased microbial burden. Some centers instruct their immunocompromised patients to consume water only if it is bottled. Many of these measures have little data to support their use outside an outbreak setting and can be costly.

Hospital facilities may elect to monitor their water quality to reduce the risk of invasive infections such as from Legionella or nontuberculous mycobacteria infection in their susceptible patients. The optimal strategy (i.e., frequency and number of sites surveyed and determination of a dose-response, bacterial burden necessary for infection) has not been determined. Cost-effectiveness studies are also unavailable.

Water damage

If not rectified, water damage in structural areas of the hospital can serve as an ideal substrate for the proliferation of mold. Water may gain access through leaking from a broken water pipe or through excessive humidity in the environment (>60%). A number of publications assert that water systems within healthcare facilities may harbor fungal contamination. Policies should outline the response plan to water damage or sustained levels of high humidity. At a minimum, repair and drying of wet materials within 72 hours or the removal of the wet material is recommended. Infection prevention professionals should ensure that appropriate containment measures to minimize dust or mold dissemination are used during repairs of water damage.

Cleaning and disinfecting environmental surfaces within hospital units

Hospital surfaces are frequently contaminated and have been implicated in transmission of HAIs among hospitalized patients. ^, Cleaning is defined as the removal of visible soil, stains, dust, and spills. Cleaning should be done as expeditiously as possible in an acute event. Disinfection is defined as the removal of many or all pathogenic micro-organisms, but may not be necessarily sporicidal. Cleaning should be performed prior to disinfection. The Environmental Protection Agency has registered disinfectants that meet safety and disinfection standards for hospital use. Manufacturer instructions for use should be stringently followed. Environmental fogging with chemical disinfectants is not recommended owing to the lack of microbicide efficacy.

To adequately eradicate C. difficile spores, disinfectants with sporicidal activity (e.g., hypochlorite-based products) are recommended. There are insufficient studies evaluating ultraviolet germicidal irradiation and other “touchless” disinfection modalities to recommend their use as part of routine C. difficile infection prevention bundles. Focal areas of cleaning should include high-touch and high-dust surfaces. Auditing cleaning efficacy with fluorescent markers and black light or an adenosine triphosphate–based system and standard aerobic cultures has been assessed in small studies, with fluorescent systems showing a slight advantage. More research is needed to determine the optimal frequency and tools used for cleaning audits.

Hematopoietic stem cell transplantation

Patients undergoing HSCT have prolonged and profound immune deficiencies. Up to four weeks might be needed for neutrophil count recovery, and immune reconstitution may be delayed with use of suppressive medications to treat GVHD. Treatment of active infection in the midst of ongoing immune deficiency is difficult; therefore prevention of infection is paramount in patients with HSCT.

The presence of central venous catheters, which are necessary for supportive medical care, is a well-known risk factor for bacteremia. Increased rates of CLABSIs often highlight a deficiency in catheter insertion and/or maintenance practices. Preemptively, facilities should undertake and maintain a reliable and reproducible workflow for line insertion and maintenance. The development and, most importantly, auditing of central line use should involve nursing leadership, vascular access specialists, infection prevention professionals, quality specialists, and physician leadership of HSCT units. These stakeholders would have a preexisting working relationship to investigate and mitigate increased incidence of CLABSIs if they occur.

Invasive fungal infections are a life-threatening complication in patients undergoing HSCT. As outlined previously, efficient HVAC systems, positive-pressure ventilation, HEPA filtration, and careful risk assessment during construction and renovation projects help to ensure safe air quality. This may mitigate the contribution of the healthcare environment to a patient’s risk of invasive fungal infection. Working toward safe air quality within the PE and to prevent invasive fungal infections requires a close and trusting relationship between infection prevention professionals and personnel in facility maintenance and design/construction. A preexisting collaboration can then be easily reassembled to investigate and mitigate possible fungal outbreaks.

The use of PPE for the prevention of HAIs in patients with HSCT may be helpful. Patients undergoing HSCT may wish to use personal N95 respirators or surgical masks to reduce environmental mold exposure while outside PE, particularly before engraftment. There are insufficient data to recommend this routinely, although it may be reassuring to patients.

Solid organ transplantation

Common pediatric transplanted organs are kidneys, lungs, and hearts. The numbers of pediatric intestinal transplants are increasing but remain relatively rare in most institutions owing to the nature of the transplants, recurrent exposure to antimicrobials, and the necessity for prolonged immunosuppression. In addition, such patients are often at risk for invasive infections with MDROs. For example, a sizable proportion of patients with CRE bacteremia had received one or more organ transplants and SOT remains an independent risk factor for invasive CRE infections. Screening for MDROs, especially VRE and MRSA, in SOT recipients may be of negligible benefit. However, there has been growing interest in screening organ donors for MDRO, although data on infection prevention and cost analysis are lacking. A focus of the infection prevention professional should be clinical surveillance and mitigation of MDRO outbreaks in SOT recipients.

Infections in transplant recipients may frequently occur at the site of the organ graft (i.e., pneumonia in lung transplant recipients; urinary tract infections in kidney transplant recipients). It is prudent for the infection prevention professional and clinician to use strategies to minimize manipulation into the new organ graft. An infection prevention program may focus efforts to limit medical devices into the graft site (such as expeditiously removing endotracheal tubes and urinary catheters) to decrease the risk of MDRO colonization or biofilm formation.

Viral infections in pediatric SOT recipients may be newly acquired or reactivated after SOT. SOT recipients may be exposed to community-acquired viruses within their homes, within the hospital, or within commonly visited centers such as school or a religious community where they spend considerable amounts of time. These patients are particularly at risk for vaccine-preventable viral infections as live vaccines may be contraindicated and vaccine responses may be attenuated by chronic immunosuppression. In addition, pretransplant vaccination rates in liver and heart transplant recipients have been historically suboptimal. Therefore infection prevention efforts should highlight the importance of appropriate hand hygiene and appropriate vaccination of SOT candidates before receiving transplant, close contacts, HCWs and the local community to reduce viral transmission.

Fungal infections with Candida or endemic molds have been rarely reported in pediatric SOT patients except in pediatric small-bowel transplant patients, among whom an invasive Candida infection develops shortly after transplant in 20% to 25% of cases .

Donor-derived infections, such as transmission of Toxoplasma from infected transplanted cardiac tissue or hepatitis from the donor transplant liver, are also of concern and protocols exist to guide pretransplant risk assessment or testing options to reduce posttransplant infections. Specific guidelines to prevent donor-derived infections are beyond the scope of this chapter.

Oncology

Infection prevention professionals may regard the infection risk of patients with oncologic disease to be minimally less than patients with HSCT. Patients with oncologic disease undergo repeated rounds of chemotherapy but have interval periods of quantitatively normal neutrophils, although neutrophil function may be impaired and thus not protective against invasive bacterial or fungal infections. Preventive measures for central line management and for optimization of air and water quality remain important. Strategies discussed previously should also be applied to oncology patients receiving chemotherapy or those admitted to the hospital.

Future areas of research in standardizing infection prevention practices

Many specific recommendations for infection prevention in immunocompromised patients are based on a common sense approach rather than on precise data. Questions remain regarding the necessity and standardization of microbiologic assessment of air and water quality, how best to minimize development and transmission of resistant pathogens, methods to decrease the burden of MDRO colonization, and the clinical and emotional impact of restricting visitation by asymptomatic individuals. Increasing healthcare costs will also foster interest in whether financial investments, such as central HEPA filtration, will have clinical value. Future studies could target these gaps and optimize care of pediatric immunocompromised patients.