Blog | Tuesday, November 29, 2011

QD: News Every Day--Scientists probe restrooms to quantify their ickiness


Public restrooms are disgusting. You knew this. You didn't need science to tell you this. Science is telling you anyway.

Wash Your Hands by jar () via Flickr and a Creative Commons licenseTo clarify exactly how gross a public restroom is, scientists wanted to learn exactly what's germinating in them and where the worst surfaces are. They sampled 10 surfaces: door handles into and out of the restroom, handles into and out of restroom stalls, faucet handles, soap dispensers, toilet seats, toilet flush handles, the floors around the toilets and floors around the sinks in six male and six female restrooms on the University of Colorado at Boulder campus were sampled on a single day in November 2010.

To determine the potential sources of bacteria on restroom surfaces and how the importance of different sources varied across the sampled locations, they used a software package, SourceTracker, which estimates the proportions of sources for each surface. Results were published at PLoS One.

Using high-throughput barcoded pyrosequencing of the 16 S rRNA gene, they found 19 total bacteria, most belonging to Actinobacteria, Bacteriodetes, Firmicutes and Proteobacteria. Communities clustered into three areas: the toilets, the restroom floor, and those found on surfaces routinely touched with hands.

On toilet surfaces, gut-associated taxa were more prevalent, suggesting fecal contamination of these surfaces. Floor surfaces were the most diverse of all communities and contained several taxa commonly found in soils. Skin-associated bacteria, especially Propionibacteriaceae, dominated surfaces routinely touched with hands. Vagina-associated Lactobacillaceae were widely distributed in female restrooms, likely from urine contamination, the authors wrote.

The authors noted that college students aren't the most likely bunch to wash their hands, which is the key to avoiding germs. But, even worse than bathrooms? The TV remote control.