Fusarium in Sink Drains

istock-000004770585small.jpgA study examining the prevalence of the Fusarium fungus in bathroom sink drains suggests that plumbing systems may be a common source of human infections.

Researchers in the college sampled nearly 500 sink drains from 131 buildings—including businesses, homes, university dormitories, and public facilities—in Pennsylvania, Maryland, Virginia, North Carolina, South Carolina, Georgia, Florida, and California. 

Fungal DNA was analyzed using multilocus sequence typing to compare the spectrum of Fusarium species and sequence types found in drains with those recovered from human infections. 

The study identified at least one Fusarium isolate in 66 percent of the drains and 82 percent of the buildings. About 70 percent of those isolates came from the six sequence types of Fusarium most frequently associated with human infections. 

“It’s clear that those buildings’ inhabitants are exposed to these fungi on a regular basis,” said lead investigator Dylan Short, who recently completed his doctorate in plant pathology. “This strongly supports the hypothesis that plumbing-surface biofilms serve as reservoirs for human-pathogenic Fusaria.” 

David Geiser, professor of plant pathology and a member of the research team, pointed out that the serious infections caused by Fusaria are relatively uncommon and that these fungi may even play positive roles in plumbing systems. But he said the study provides the strongest evidence to date supporting an epidemiological link between human fusarioses and plumbing systems. 

Some species of Fusarium also cause opportunistic and sometimes fatal infections in humans, typically entering the body through wounds or trauma, via catheters and intravenous devices, or by introduction of a biofilm to the eye. While relatively rare, Fusarium infections can be difficult to treat due to the organism’s resistance to many antifungal drugs. Those most at risk are individuals with weak or compromised immune systems. 

Study results were published in the December issue of the Journal of Clinical Microbiology.