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11-12-2011 | General practice | Article

Contamination of restroom surfaces by pathogenic bacteria common


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MedWire News: Study findings show that human-associated bacteria dominate most public restroom surfaces, with different strains colonizing toilet surfaces, floors, and areas routinely touched with the hands.

"The prevalence of gut and skin-associated bacteria throughout the restrooms we surveyed is concerning, since enteropathogens or pathogens commonly found on skin (eg, Staphylococcus aureus) could readily be transmitted between individuals by the touching of restroom surfaces," say Noah Fierer (University of Colorado, Boulder, USA) and co-authors.

For the study, the researchers identified bacterial communities found on 10 surfaces in 12 public restrooms in Colorado using high-throughput barcoded pyrosequencing of the 16 S recombinant RNA gene.

A total of 19 phyla were observed across all restroom surfaces, with approximately 92% of sequences classified as Actinobacteria, Bacteroidetes, Firmicutes, or Proteobacteria.

Taxa typically associated with human skin (eg, Propionibacteriacae, Corynebacteriaceae, Staphylococcaeae, and Streptococcaeae) were commonly found on all surfaces, as were several lineages associated with the gut, mouth, and urine.

When the team compared bacterial communities found on different restroom surfaces, they found that these could be classified as those found on toilet surfaces (seat and flush handle), the restroom floor, and surfaces routinely touched with hands (entrance door, stall door, faucet/tap handles, and soap dispenser).

Skin-associated bacteria dominated surfaces routinely touched by hands, while toile flush handles and seats were rich in human gut-associated bacteria, such as Firmicutes and Bacteroidetes. Bacteria commonly associated with soil were on average more abundant on floor surfaces.

Lactobacillaceae were significantly more abundant on toilet surfaces and those touched by hands after using the toilet within female restrooms compared with male restrooms, suggesting that contamination with urine had occurred.

Writing in the journal PLoS ONE, the researchers say: "Coupling these observations with those of the distribution of gut-associated bacteria indicate that routine use of toilets results in the dispersal of urine- and fecal-associated bacteria throughout the restroom.

"While these results are not unexpected, they do highlight the importance of hand hygiene when using public restrooms since these surfaces could also be potential vehicles for the transmission of human pathogens."

By Ingrid Grasmo

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