WEDNESDAY, Dec. 28 (HealthDay News) -- Disease-causing strains of the fungus Fusarium are present in bathroom sink drains, which may be a common source of infection in humans, according to a new study.

Fusarium is well known for causing diseases in agricultural crops, but some species of the fungus can cause potentially dangerous and even fatal infections in humans.

For example, Fusarium was the cause of an outbreak of fungal keratitis (infection of the cornea) among contact lens wearers in the United States in 2005-2006.

Fusarium infections can be difficult to treat because Fusarium is resistant to many antifungal drugs, explained Penn State researchers.

They tested samples taken from nearly 500 sink drains in 131 businesses, homes, university dormitories and public facilities in Pennsylvania, Maryland, Virginia, North Carolina, South Carolina, Georgia, Florida and California.

At least one Fusarium isolate was found in 66 percent of the drains and in 82 percent of the buildings. About 70 percent of those isolates were from species most frequently associated with human infections.

"With about two-thirds of sinks found to harbor Fusarium, it's clear that those buildings' inhabitants are exposed to these fungi on a regular basis," lead investigator Dylan Short, of the College of Agricultural Sciences, said in a university news release. "This strongly supports the hypothesis that plumbing-surface biofilms serve as reservoirs for human pathogenic fusaria."

The study is in the December issue of the Journal of Clinical Microbiology.

More information

The American Academy of Ophthalmology has more about fungal keratitis.