Written by Joyce Smith, BS. Study demonstrates that toilets contaminated with Clostridium difficile spores can be a persistent source of environmental contamination.
Clostridium difficile, an endospore-forming anaerobic bacteria responsible for infectious diarrhea, pseudomembranous colitis, and toxic megacolin, is increasing in morbidity and mortality in the United States 1,2. Often seen as a complication of antibiotic overuse, it carries a high relapse rate with increased severity of successive infections and demonstrating a disproportionate affinity for women and the elderly. 3 Identifying contamination routes has sparked the interest of the scientific community. Research has documented spore survival on contaminated surfaces up to a period of five months4, yet other research has linked increased infection susceptibility to rooms of patients with active C. difficile infection (CDI), where eradication appeared to be effective with the conscientious use of sporicidal cleaners 5. Additional research has proven otherwise with the discovery of infectious strains recovered from bedsides of both confirmed CDI and control patients 6. The testing of toilet bowls confirmed the toilet as an aerosol generation device and a potential source of continuing contamination 7.
Aithinne et al conducted the following study 8 to further characterize the persistence of bacterial endospores in toilet water and the generation of aerosol after a series of consecutive flushes as well as the contamination of surrounding surfaces by the liquid droplets. In a sealed chamber, they seeded a flush toilet with C. difficile spores. They flushed the toilet 24 times and periodically collected post-flush bowl water samples and settle plates for culturing and counting the growth of spore colonies of C. difficile. Air samples were collected as well after each of 12 flushes using rotating plate impactors.
Researchers found that toilets contaminated with C. difficile spores produced numerous large droplet and droplet nuclei bioaerosols that could contaminate surfaces near and away from the source. They also found that microbial contamination persisted in the water of the toilet bowel for many flushes after the initial contamination and produced bioaerosol with each flush. Furthermore, C. difficile surface contamination accumulated as a large droplet and droplet nuclei spore bioaerosol, the production of which continued for many flushes. They believe this droplet nuclei C. difficile spore aerosol has the potential to travel with air currents throughout a hospital and contaminate surfaces beyond the rooms of those infected with C. difficile.
This persistent source of environmental contamination has significant implications for public toilet use where persons shedding C. difficile spores or other gastrointestinal contaminants, in particular, the highly contagious norovirus, may contaminate a public toilet and subsequently might contaminate other users. According to Aithinne and colleagues, the transmission path is two-fold and may occur from exposure to accumulated toilet surface contamination or from inhaling bioaerosol introduced by flushing. They recommend that in hospitals and other health care environments more diligent toilet bowl disinfecting should be done to eliminate surface contamination. Also, consideration should be given to the air currents produced by heating, ventilation and air conditioning systems that could potentially carry droplet nuclei of bioaerosols to other surfaces beyond the infected patient rooms.
Source: Aithinne, Kathleen AN, Casey W. Cooper, Robert A. Lynch, and David L. Johnson. “Toilet plume aerosol generation rate and environmental contamination following bowl water inoculation with Clostridium difficile spores.” American journal of infection control 47, no. 5 (2019): 515-520.
© 2018 Association for Professionals in Infection Control and Epidemiology, Inc.
Posted March 30, 2020.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
References:
- Lessa FC, Mu Y, Bamberg WM, et al. Burden of Clostridium difficile infection in the United States. New England Journal of Medicine. 2015;372(9):825-834.
- Rutala WA, Weber DJ. Role of the hospital environment in disease transmission, with a focus on Clostridium difficile. Healthcare infection. 2013;18(1):14-22.
- Lucado J, Gould C, Elixhauser A. Clostridium difficile infections (CDI) in hospital stays, 2009: statistical brief# 124. 2006.
- Kim K-H, Fekety R, Batts DH, et al. Isolation of Clostridium difficile from the environment and contacts of patients with antibiotic-associated colitis. Journal of infectious diseases. 1981;143(1):42-50.
- Weber DJ, Rutala WA, Miller MB, Huslage K, Sickbert-Bennett E. Role of hospital surfaces in the transmission of emerging health care-associated pathogens: norovirus, Clostridium difficile, and Acinetobacter species. American journal of infection control. 2010;38(5):S25-S33.
- Best EL, Fawley WN, Parnell P, Wilcox MH. The potential for airborne dispersal of Clostridium difficile from symptomatic patients. Clinical Infectious Diseases. 2010;50(11):1450-1457.
- Johnson DL, Lynch RA, Villanella SM, et al. Persistence of bowl water contamination during sequential flushes of contaminated toilets. Journal of environmental health. 2017;80(3):34.
- Aithinne KA, Cooper CW, Lynch RA, Johnson DL. Toilet plume aerosol generation rate and environmental contamination following bowl water inoculation with Clostridium difficile spores. American journal of infection control. 2019;47(5):515-520.
