Environmental Infection Control

Clostridium difficile Excerpt: Guideline for Environmental Infection Control in Health-Care Facilities, 2003

Source: CDC. Sehulster L, Chinn RYW. Guidelines for environmental infection control in healthcare facilities. MMWR 2003;52(RR10);1–42.

7. Special Pathogen Concerns

b. Clostridium difficile

Clostridium difficile is the most frequent etiologic agent for health-care–associated diarrhea. In one hospital, 30% of adults who developed health-care–associated diarrhea were positive for C.difficile. One recent study employing PCR-ribotyping techniques demonstrated that cases of C.difiicile-acquired diarrhea occurring in the hospital included patients whose infections were attributed to endogenous C. difficile strains and patients whose illnesses were considered to be health-care–associated infections. Most patients remain asymptomatic after infection, but the organism continues to be shed in their stools. Risk factors for acquiring C. difficile-associated infection include a) exposure to antibiotic therapy, particularly with beta-lactam agents; b) gastrointestinal procedures and surgery; c) advanced age; and d) indiscriminate use of antibiotics. Of all the measures that have been used to prevent the spread of C. difficile-associated diarrhea, the most successful has been the restriction of the use of antimicrobial agents.

C. difficile is an anaerobic, gram-positive bacterium. Normally fastidious in its vegetative state, it is capable of sporulating when environmental conditions no longer support its continued growth. The capacity to form spores enables the organism to persist in the environment (e.g., in soil and on dry surfaces) for extended periods of time. Environmental contamination by this microorganism is well known, especially in places where fecal contamination may occur. The environment (especially housekeeping surfaces) rarely serves as a direct source of infection for patients. However, direct exposure to contaminated patient-care items (e.g., rectal thermometers) and high-touch surfaces in patients’ bathrooms (e.g., light switches) have been implicated as sources of infection.

Transfer of the pathogen to the patient via the hands of health-care workers is thought to be the most likely mechanism of exposure. Standard isolation techniques intended to minimize enteric contamination of patients, health-care–workers’ hands, patient-care items, and environmental surfaces have been published. Handwashing remains the most effective means of reducing hand contamination. Proper use of gloves is an ancillary measure that helps to further minimize transfer of these pathogens from one surface to another.

The degree to which the environment becomes contaminated with C. difficile spores is proportional to the number of patients with C. difficile-associated diarrhea, although asymptomatic, colonized patients may also serve as a source of contamination. Few studies have examined the use of specific chemical germicides for the inactivation of C. difficile spores, and no well-controlled trials have been conducted to determine efficacy of surface disinfection and its impact on health-care–associated diarrhea. Some investigators have evaluated the use of chlorine-containing chemicals (e.g., 1,000 ppm hypochlorite at recommended use-dilution, 5,000 ppm sodium hypochlorite [1:10 v/v dilution], 1:100 v/v dilutions of unbuffered hypochlorite, and phosphate-buffered hypochlorite [1,600 ppm]). One of the studies demonstrated that the number of contaminated environmental sites was reduced by half, whereas another two studies demonstrated declines in health-care–associated C. difficile infections in a HSCT unit and in two geriatric medical units during a period of hypochlorite use. The presence of confounding factors, however, was acknowledged in one of these studies. The recommended approach to environmental infection control with respect to C. difficile is meticulous cleaning followed by disinfection using hypochlorite-based germicides as appropriate. However, because no EPA-registered surface disinfectants with label claims for inactivation of C. difficile spores are available, the recommendation is based on the best available evidence from the scientific literature.


VI. Special Pathogens

G. Because no EPA-registered products are specific for inactivating Clostridium difficile
spores, use hypochlorite-based products for disinfection of environmental surfaces in those patient-care areas where surveillance and epidemiology indicate ongoing transmission of C. difficile. Category II

H. No recommendation is offered regarding the use of specific EPA-registered hospital
disinfectants with respect to environmental control of C. difficile. Unresolved issue

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