Infection Control, Prophylaxis, and Vaccinations in Hematopoietic Cell Transplantation Recipients

Room Ventilation and Protective Environments

All allogeneic HCT recipients should be placed in rooms with protective environments, and such arrangements are preferable for autologous HCT patients. Protective environment rooms are characterized by a wide range of interventions, including the management of ventilation by positive air flow inside the rooms relative to the air flow in the adjacent spaces, bathrooms, anterooms, and corridor. The rooms should have 12 or more air changes per hour. They should also use high-efficiency particulate air filters, which decrease the risk of healthcare-associated invasive aspergillosis. Studies have shown that these filters remove around 99.97% of particles larger than 0.3 mm.

Construction, Renovation, and Cleaning in the Healthcare Setting

When construction, renovation, or maintenance projects occur within healthcare settings, specific precautions must be implemented given the greater risk of exposure to fungal microorganisms (primarily Aspergillus or Legionella species). Infectious particles can be released from the water supply or during the construction, destruction, or renovation of buildings. Whenever possible, HCT recipients should avoid construction as well as renovation areas. Importantly, hospital construction areas should maintain negative air pressure relative to the air pressure in the patient care areas, and the air should be released outside the hospital milieu or filtered with high-efficiency particulate air filters. Special attention should be given to cleaning, as it is indispensable during and after any construction activity. Also, HCT units should be cleaned once per day using hospital disinfectant and, importantly, should be kept dust-free.

Hand Hygiene

Appropriate hand hygiene is the single most essential practice for preventing the transmission of nosocomial infections and limits the spread of many infectious agents within healthcare settings. All healthcare workers should wash their hands in a systemic fashion before entering and after leaving patient rooms. Similarly, HCT recipients and their household members should be encouraged to practice handwashing hygiene with antimicrobial soap and water.

Isolation and Barrier Precautions

Barrier precautions and isolation measures should be implemented in all HCT centers to prevent patients and healthcare workers from acquiring communicable or infectious diseases. Hospital isolation practices encompass two levels of protection: standard precautions that apply to all patients and expanded precautions that are tailored according to the nature of microorganism transmission. Contact, droplet, and airborne precautions are commonly implemented in addition to standard measures to ensure protectiveness based on potential infections (see later for the isolation precautions for specific pathogens).

Plants, Toys, and Play Areas

To reduce the risk of mold or bacterial nosocomial transmission, live plants and flowers should be excluded from HCT patients’ hospital rooms. Studies have shown that plants and flowers may contain numerous microorganisms such as Pseudomonas aeruginosa , Burkholderia cepacian , and Aeromonas hydrophila . It is also noteworthy that the water from flower vases may harbor pathogenic fungi and multiresistant infectious agents. Special attention should also be given to pediatric patients’ toys and play areas, as previous outbreaks of rotavirus and norovirus have been linked to communal toys. P. aeruginosa infection from water-retaining bath toys has been described as well. Therefore cleaning and disinfecting toys and play areas are essential in pediatric HCT units.

Dietary Principles and Food Safety

To prevent food-borne diseases, HCT recipients’ food should be prepared carefully and attention should be given to the food types offered and their appropriate storage and handling. HCT patients should avoid unwashed vegetables and fruits, undercooked or raw meat, seafood, and eggs. The U.S. Department of Agriculture’s food safety recommendations for patients with cancer advises consuming only pasteurized dairy products and washing hands with soap and water before handling, preparing, and eating foods. Stricter restrictions have been recommended for HCT recipients and patients with neutropenia (those with an absolute neutrophil count below 500 cells/mm ³ ) include the avoidance of raw fruits and vegetables, undercooked meat, and unpasteurized milk and cheese. Recent data, however, have shown that there is no major reduction in infectious risk in patients who followed the strict neutropenic diet recommendations after HCT compared to those who followed a general hospital diet.

Central Line–Associated Bloodstream Infections

Central line–associated bloodstream infections (CLABSIs) are a major cause of hospital-associated infections. Only competent and well-trained healthcare personnel should be allowed to insert, maintain, and care for central venous catheters (CVCs), and they should adhere to evidence-based guidelines. Cancer patients, including HCT recipients, are at greater risk of CLABSIs secondary to host-related factors—such as sex, age, and the presence of mucositis—and nonhost-related factors mainly related to prolonged hospitalization, prolonged central line use, and the use of multilumen CVCs. The Centers for Disease Control and Prevention’s guidelines for the prevention of CLABSIs call for practices such as: a) the insertion of CVC bundles, which entails the use of aseptic measures (e.g., hand hygiene, barrier precautions, and the use of chlorhexidine during catheter placement); b) the use of maintenance or postinsertion CVCs bundles, which involves daily assessment of the catheter insertion site, cleaning the infusion hub, dressing changes, and assessing the need for CVCs; c) the use of antimicrobial-impregnated CVCs; and d) the use of sutureless devices for securing CVCs.

Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) screening practices for HCT recipients are not well standardized and the current guidelines do not recommend routine screening for MRSA carriage. The data on MRSA carriage, screening, and outcomes in HCT patients are limited. A large, retrospective cohort study evaluated the prevalence of MRSA in patients before HCT showed that pretransplantation MRSA colonization was not associated with postransplantation MRSA-related complications. This finding was unexpected, given that HCT recipients have multiple risk factors for MRSA acquisition, including prolonged hospital stays, frequent antibiotic exposures, and common usage of intravascular devices.

All healthcare personnel in HCT units should apply the standard isolation and precautionary measures for patients with MRSA infection or colonization, including frequent handwashing between patients and use of gloves and gowns when in contact with MRSA-infected or colonized patients. For patients with a history of recurrent MRSA infection and colonization, decolonization via chlorhexidine baths and the application of 2% mupirocin ointment should be considered.

Vancomycin-Resistant Enterococci

Vancomycin-resistant enterococci (VRE) are now a major problem among allogeneic HCT recipients and are a primary cause of nosocomial bloodstream infections (e.g., bacteremia) at some transplant centers, particularly in the early posttransplant. Unlike MRSA carriage, VRE carriage in the pretransplant period is associated with VRE-related infectious complications posttransplantation, and VRE bacteremia has been reported in 11% to 34% of VRE-colonized patients. Therefore HCT candidates and recipients should be screened for VRE carriage during hospitalization to detect the bacteria early and minimize their transmission. To limit VRE transmission, strict adherence to infection control practices (e.g., washing hands with soap and water or alcohol-based solution) is essential. Patients with VRE should be placed under contact precautions until all antibiotics are discontinued and repeat cultures are negative. Patient rooms, including equipment and all surfaces, should be cleaned and disinfected daily.

Clostridium difficile Infection

The golden rule in controlling Clostridium difficile infection (CDI) is to administer antimicrobials for the shortest possible duration and improve the use of appropriate antibiotics. CDI is more prevalent in transplant recipients, including solid organ and HCT recipients, than in other hospitalized patients. Nosocomial CDI is primarily transmitted horizontally (spread from one individual to another) in hospital settings and the bacteria are often present on the hands of healthcare workers. All patients with CDI should be placed under contact precautions for the duration of infection; some centers isolate these patients for their entire hospital stay. Hospital personnel treating them should wear gowns and gloves and should focus on frequent handwashing with soap and water. CDI should be treated as recommended by the Infectious Diseases Society of America guidelines. Of interest, recent studies evaluated the effectiveness of CDI prophylaxis with oral vancomycin (125 mg given twice daily) on the incidence of CDI rates in HCT patients and found that oral vancomycin was highly effective in preventing CDI in allogeneic HCT recipients and did not increase the risk of GVHD or disease relapse.