Clostridium Difficile: the dangers of flushing toilets

Clostridium difficile is an anaerobic, endospore-forming bacterium responsible for thousands of infections. It is the leading cause of healthcare-associated gastric disease, and mortality and morbidity rates are rising. Environmental contamination by C. difficile spores is a risk factor for transmission through contact, notably by flushing. Consequently, it has become important to identify contamination routes in order to prevent patient colonization and infection.

A study was carried out to demonstrate the persistence of spores in toilets and the environment during a series of flushes after contamination with Clostridium Difficile.4

A flush toilet was inoculated with a non-pathogenic strain of C. difficile spores in a hermetically sealed chamber. The toilet seat was lowered, as in actual use, and the flapper was raised to simulate the lidless toilets found in hospitals. The toilet was flushed 24 times, with post-flush bowl water samples taken periodically.
Petri dishes with nutrient agar were placed in predefined positions on the floor surrounding the toilet.

The results of the study highlighted the danger of flushing contaminated excreta down the toilet: 


  • The spores were still present in the toilets, even after 24 flushes.
  • With regard to Petri dishes for assessing surface contamination of the environment: over the series of tests, every location on the floor had at least 1 positive sample. Cumulative surface density for all dishes combined was 553 CFU/m2 after 24 flushes. Around 75% of this level was reached after just 4 flushes and 90% after just 9 flushes.
  • Bioaerosols of spore droplets were produced during at least 12 consecutive flushes.

The results of this study demonstrate that toilets contaminated with C. Difficile spores are a persistent source of environmental contamination: the microbial contamination will persist in the bowl water for a large number of flushes after the initial contamination, and will produce bioaerosols with each flush, potentially contaminating surfaces near and far from the source.

In addition, the aerosol of C. difficile spores could circulate with air currents throughout the facility, contaminating surfaces outside the rooms of C. difficile-infected patients.

Single-use solutions: a more efficient alternative

This study shows that raising awareness among nursing staff of good practices for preventing infectious risk is key. The results of this study also show that the use of single-use solutions for the collection of excreta is an interesting solution for confining infectious risk directly at source, limiting the spread of pathogens such as C. Difficile and, consequently, the risk of cross-transmission or, worse still, an epidemic within the facility.


4. Source : A.N.  AITHINNE,  A.  et  al.  “Toilet   plume   aerosol   generation   and environmental  contamination  following  bowl  water  inoculation  with Clostridium difficile spores”, American Journal of Infection Control, N°47 (2019), pp. 515- 520