You most likely don’t make a habit of using your bathroom sink as a salad-mixing bowl. But in case you’ve ever been tempted to snatch a contact lens out of the drain and put it back in your eye, you should know that sink drains are ripe with fungi, many of which can cause severe human infections.
Dylan Short of Pennsylvania State College and his colleagues sampled almost 500 bathroom sink drains in 131 buildings (ranging from homes to dorms to public facilities) across eight U.S. states. 82% of the buildings and 66% of the sinks harbored at least one type of Fusarium, a genus of fungus known to cause infections in humans and agricultural plants. In fact, plumbing systems were most likely the culprit behind an outbreak of fungal eye infections among contact lens wearers six years ago.
It may not all be bad news. Although 70% of the Fusarium species found in sink drains were associated with human disease, the other 30% may actually play some beneficial roll. At least, that’s the optimistic view of author David Geiser. Either way, don’t skimp on the contact lens cleaner, and don’t drop your toothbrush in the drain.