By J. Darrel Hicks, Contributing Writer

A hospital transplant unit in France found cases of healthcare-associated Legionnaires’ disease in two patients. The patients had been hospitalized five months apart but in the same room. Whole-genome sequencing analyses showed that clinical isolates from the patients and isolates from the room’s toilet clustered together. 

Researchers believed that toilet contamination by Legionella pneumophila could lead to a risk of exposure through flushing. Their research included closing the affected room and disinfecting the toilet daily with bleach. The toilet water in the room was monitored through iterative testing. Results were negative from 10 successive samples tested between June 2016 and November 2017. 

To determine the extent of such contamination, researchers analyzed 29 toilets in five different hospital buildings. All samples were negative, suggesting that Legionella pneumophila contamination of toilet water was not common.  

The research describes two cases in which Legionnaires’ disease probably was caused by Legionella pneumophila transmitted through contaminated toilet water that became aerosolized during flushing. Researchers found little to no detectable difference between whole genomes in isolates obtained from two patients hospitalized five months apart in the same room and those from the toilet in that room. The other commonly suspected sources — in this case, the shower and the sink — tested negative for Legionella pneumophila. 

This investigation suggests that transmission of Legionella pneumophila through toilet flushing should be considered when investigating a Legionnaires’ disease case. But as previously suggested, there remains a need for a laboratory-based study to explore whether flushing toilets can generate and spread contaminated aerosols. 

Flushing a toilet causes a plume of enteric pathogens. When a toilet is flushed in a patient’s restroom, it produces a substantial aerosol plume containing potentially infectious particles, including bacteria, spores, Candida auris and viruses. Flush particles rapidly rise out of the bowl and several feet into the air after flushing. 

After an infected person or patient uses the toilet, the pathogens can remain in the bowl even after dozens of flushes. When expelled into the air during a flush, the viruses and bacteria then can make their way into the lungs of subsequent bathroom users. 

Research has shown that these aerosols can: 

• rise rapidly out of the bowl, reaching heights of 4.9 feet within eight seconds 
• travel up to 6.6 feet per second 
• spread onto nearby high-touch surfaces, including faucet handles, handicap grab bars, doorknobs, light switches and towels 
• remain airborne for extended periods, with particles of less than 5 microns staying aloft for over a minute. 

The toilet plume has been identified as a potential vector for the transmission of various pathogens of concern, including C. difficile, Legionella, C. auris, norovirus and Ebola. These pathogens can survive on surfaces for days, weeks or even months, posing a risk of infection to subsequent restroom users. 

Should environmental services managers be testing the water in the toilet? Faced with an outbreak of one of these pathogenic organisms, they should test the water in patient room toilets. It might be the vector for the pathogen of concern.  

J. Darrel Hicks, BA, MESRE, CHESP, Certificate of Mastery in Infection Prevention, is the past president of the Healthcare Surfaces Institute. Hicks is nationally recognized as a subject matter expert in infection prevention and control as it relates to cleaning. He is the owner and principal of Safe, Clean and Disinfected. His enterprise specializes in B2B consulting, webinar presentations, seminars and facility consulting services related to cleaning and disinfection. He can be reached at darrel@darrelhicks.com, or learn more at www.darrelhicks.com.