What is the viable microbiome of the healthcare toilet?

Background

Flushing water toilets in hospitals cater for staff and patients, including disabled and unisex facilities. The recent introduction of unisex toilets has highlighted potential microbiological risks between different bathroom facilities.

Aim

This project sought to establish the cultivable microbiome in all types of healthcare toilet.

Methods

Systematic sampling was performed using quantitative and qualitative microbiology within a multi-site longitudinal study. Hand-touch sites, low sites (floors) and high sites (ceilings) in male/female staff and patient, unisex and disabled facilities were screened in three hospitals. Aerobic colony count (ACC) was determined alongside identification of key pathogens (Staphylococcus aureus, Enterobacterales, enterococci, stenotrophomonas, acinetobacter and fungi). Bacterial pathogens were tested for antimicrobial susceptibilities.

Findings

Expected environmental and skin flora were present at all sites. Bioburden was heaviest on floors, closely followed by ceilings. Hand-touch sites were cleanest (<2.5 cfu/cm²) in all toilets (P=0.003), with those in female toilets cleaner than in male toilets (P=0.008). Highest bioburden overall (>12 cfu/cm²) occurred in unisex toilets, followed by male toilets. Flora at high sites was almost identical to that on floors. Bacterial pathogens, including resistant bacteria, were concentrated on patient floors, with 80% isolated alongside ACC>2.5 cfu/cm². Seven of eight Stenotrophomonas maltophilia were recovered from gender-neutral toilets. S. aureus predominated on floors and hand-touch sites in male staff and disabled toilets (P=0.02 and P<0.001, respectively).

Conclusion

Cleaning frequencies should be modelled against higher bioburden (unisex) and risk of pathogens (patient toilets). Similar flora on floors and ceilings suggested aerosolization during flushing. The data provides evidence to inform bathroom design, designation and decontamination practices.