To all of my blog friends: Except where absolutely required, please stay out of hospitals - as patient or as visitor. The following excerpts from Hospital Microbiome explain why I make the request. If you find the subject of interest, I recommend clicking on the link to read the whole article. (I post only the references used within the excerpts.)
Contrary to public expectation, the potential for contracting a microbial pathogen is highest within a hospital environment, and these infections are much more likely to be fatal. The Centers for Disease Control and Prevention identified 1.5 million cases of environmentally-contracted notifiable diseases in the United States for 2002 , 15,743 of which resulted in death (1 %) . In comparison, during the same year, estimates of healthcare associated infections (HAI) in the United States was 1.7 million, a rate of 4.5 infections per 100 hospital admissions, which contributed to an astonishing 99,000 deaths (6%) . This sobering statistic places HAIs as the 6th leading cause of death, ahead of diabetes, influenza/pneumonia, and Alzheimer’s . Circumstantial evidence suggests that agent transfer between surfaces and humans is the most important transmission route, and therefore, hospitals are likely to be the foremost ecosystem for studying the transfer of microorganisms between humans and a built environment.
Currently there is a lot of misinformation about the whole idea of where infection comes from in the hospital setting, i.e. infected instruments, water supply, keyboards, human hands, noses, sheets, etc. The real question to ask is geo-spatially how does the microbiome of a hospital organize? The only way to know that is to study it before patients and personnel are there, and then to track how the structure (and key elements that it houses) become colonized, and from where the infection originates. Or if such colonization does not occur, what the potential mode of transmission might be. The new knowledge to be gained is that humans infect the structure, but the infected structure itself does not cause the infections (hypothesis to be tested). Sick patients enter the hospital with lots of pathogens (they have received antibiotics, chemotherapy, etc), they are then likely to leave a microbial/viral footprint in the locations they have been, whether by air or physical transmission. We then identify these microbes on objects like keyboards and personnel like nurses’ fingers, leading to misleading blame on the mode of transmission, when these most often, causally, represent rare events. There is circumstantial evidence that hands are the most common vehicle for the transmission of HAIs within a hospital, which has led to the assumption that hand-washing is the leading measure for preventing the spread of antimicrobial resistant infections . Unpublished data suggests that hand washing reduces infection only by about 3-5%, and while this helps, infection rates are going up not down. The most compelling evidence we have of the association between environmental contamination and patient infection comes from unpublished studies that demonstrate circumstantial evidence of an increased risk for multi-drug resistant organism infections among hospital patients occupying a bed space that was previously occupied by an infected or colonized patient. However, these analyses are somewhat limited, even when multiple confounders are considered in the analysis. The need for education is highlighted by unpublished studies that explore aggregated hand hygiene performance, which typically only examines a limited number of hand hygiene opportunities, yet suggest that studies where hand-washing is reported may be woefully overestimating of rates.
- Groseclose SL, Brathwaite WS, Hall PA, Connor FJ, Sharp P, et al. (2004) Summary of Notifiable Diseases — United States, 2002. MMWR Morb Mortal Wkly Rep 51: 1–84.
- Hall-Baker PA, Nieves E, Jajosky RA, Adams DA, Sharp P, et al. (2010) Summary of Notifiable Diseases — United States, 2008. MMWR Morb Mortal Wkly Rep 57: 1–100.
- Klevens RM, Edwards JR, Richards CL Jr, Horan TC, Gaynes RP, et al. (2007) Estimating health care-associated infections and deaths in U.S. hospitals, 2002. Public Health Rep 122: 160–166.
32. Allegranzi B, Pittet D (2009) Role of hand hygiene in healthcare-associated infection prevention. Journal of Hospital Infection 73: 305–315.doi:10.1016/ j.jhin.2009.04.019.