Restrooms are comparably no more healthy or unhealthy than a typical home, with outdoor and human pathogens found on bathroom surfaces similar to other built environments, according research published ahead of print in Applied and Environmental Microbiology by the American Society for Microbiology.
Following the decontamination of each surface, researchers characterized the structure, function and abundance of the microbial community on floors, toilet seats and soap dispensers in restrooms. They analyzed each surface hourly at first, then on a daily basis, for eight weeks.
"We hypothesized that while enteric bacteria would be dispersed rapidly due to toilet flushing, they would not survive long, as most are not good competitors in cold, dry, oxygen-rich environments," Jack A. Gilbert, PhD of San Diego State University and author of the study. "As such, we expected the skin microbes to take over — which is exactly what we found."
The microbial communities associated with each surface became increasingly similar in species and abundance within five hours of the initial sterilization, and the late-successional surface community structure remained relatively unchanged for the remainder of the eight week sampling period.
Toilet seat samples in ladies' rooms were dominated by Anaerococcus — vaginal flora — and men's rooms saw an abundance of gut-associated Roseburia and Blautia. Ultimately, however, skin and outdoor-associated taxa accounted for 68 to 98 percent of cultured communities, with fecal taxa comprising just zero to 15 percent of these. Outdoor-associated taxa was predominant is restrooms both prior to and well after sterilization, suggesting human-associated bacteria need to be dispersed in restrooms in order to be maintained there over the long-term.
"A key criterion of healthy or unhealthy might be the presence or relative abundance of pathogens. While we found cassettes associated with methicillin-resistant Staphylococcus aureus (MRSA), the predominant Staph organisms didn't harbor those genes, so MRSA may be there but it is very rare," Dr. Gilbert said.