Controlling hospital-acquired infection: focus on the role of the environment and new technologies for decontamination

Abstract

There is increasing interest in the role of cleaning for managing hospital-acquired infections (HAI). Pathogens such as vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA), multiresistant Gram-negative bacilli, norovirus, and Clostridium difficile persist in the health care environment for days. Both detergent- and disinfectant-based cleaning can help control these pathogens, although difficulties with measuring cleanliness have compromised the quality of published evidence. Traditional cleaning methods are notoriously inefficient for decontamination, and new approaches have been proposed, including disinfectants, steam, automated dispersal systems, and antimicrobial surfaces. These methods are difficult to evaluate for cost-effectiveness because environmental data are not usually modeled against patient outcome. Recent studies have reported the value of physically removing soil using detergent, compared with more expensive (and toxic) disinfectants. Simple cleaning methods should be evaluated against nonmanual disinfection using standardized sampling and surveillance. Given worldwide concern over escalating antimicrobial resistance, it is clear that more studies on health care decontamination are required. Cleaning schedules should be adapted to reflect clinical risk, location, type of site, and hand touch frequency and should be evaluated for cost versus benefit for both routine and outbreak situations. Forthcoming evidence on the role of antimicrobial surfaces could supplement infection prevention strategies for health care environments, including those targeting multidrug-resistant pathogens.

FIG 1

Relationship between environmental bioburden and hospital-acquired infection. This figure shows a relationship between the number of surgical intensive care unit (SICU)-acquired infections and total hygiene fails during a 2-month patient and environmental surveillance study in a Glasgow teaching hospital. Hygiene failures were defined as aerobic colony counts (ACCs) of >2.5 CFU/cm² and/or the presence of Staphylococcus aureus on hand touch sites (42).

FIG 2

How should we clean clinical equipment? This figure shows data from a study examining three different methods for cleaning a dental chair. Cleaning (wipe-rinse method) using a sodium lauryl sulfate-based detergent demonstrated equivalence to use of a disposable barrier and bleach disinfection for reducing MRSA contamination on a dental chair (164). (Photo courtesy of S. Petti.)

FIG 3

Effect of detergent and disinfectant cleaning on total Staphylococcus aureus (methicillin-susceptible S. aureus [MSSA] and methicillin-resistant S. aureus [MRSA]) recovered from hand touch sites on a 30-bed ward over 48 h. This figure shows the effects of detergent (blue line) and disinfectant (red line) on surface S. aureus and MRSA from baseline levels over 48 h on a 30-bed acute ward. Both types of cleaning rapidly reduced the overall staphylococcal burden, but recontamination occurred more rapidly after disinfectant exposure. The sites monitored were bedside locker, bed frame, and overbed table, and each 48-h period for each type of cleaning was repeated three times (276). (Adapted from reference .)