Common Home Fixtures May Be Killing You
Infection-causing organisms are ubiquitous in nature. No matter how well you may keep your home clean, hidden dangers lurk in some of the most unusual places in the most common home fixtures—and they may be killing you. Researchers recently report their discovery of what they believe is a previously undetected source of infection from common home fixtures found not only in homes, but in hospitals, work places and public facilities too.
Think about it. Have you ever had your dishwasher backup its grey water into your sink? Have you ever stood in a shower only to discover that your drain was clogged and refluxing drain water around your feet? Have you ever had to dig into a bathroom sink to unclog a sink? Unless you live in a tent, the odds are you have experienced at least one of the three this past month.
The danger of all three is that your sink drain is an ideal habitat for harmful fungal species that thrive as biofilms that cling to your plumbing like cholesterol to your arteries. A biofilm is comprised of living microorganisms, such as bacteria, that exist as a colony or community on a particular surface. Examples of biofilms are the slippery surfaces of rocks in a freshwater stream and the coating of plaque on your teeth. Think of a biofilm as a special ecological niche where particular microorganisms live and thrive.
In a recent study published in the Journal of Clinical Microbiology, researchers have discovered that a particularly nasty fungal species called “Fusarium” thrives as a biofilm inside common home fixtures—sink drains.
Species of Fusarium are well-known for the diseases they cause on grains and greenhouse crops. The danger to humans from crop-derived sources of Fusarium is through ingesting mycotoxins produced by Fusarium on the crops.
However, a more direct and lethal connection between man and Fusarium is through infection via open wounds, urinary catheters, IV devices, and contact lens supplies. Fusarium is an opportunistic pathogen meaning that it can thrive not only as a biofilm in sink drains and on sink and tub surfaces, but also in other habitats such as your bloodstream.
The difficulty with treating Fusarium infections is that some species are very resistant to antifungal medications. In addition, most antifungal medications are toxic to the liver and cannot be used safely in many patients. One widely publicized case of Fusarium infection in 2005-06 was an outbreak of fungal keratitis— an infection of the cornea—among individuals who wear contact lenses.
In the published study, researchers from Penn State's College of Agricultural Sciences sampled approximately 471 sink drains from 131 buildings that included businesses, homes, university dormitories and public facilities in Pennsylvania, Maryland, Virginia, North Carolina, South Carolina, Georgia, Florida and California.
From the sink drain swabs they isolated 297 Fusarium samples. DNA from the samples was then analyzed and compared to the DNA sequence types of Fusarium species commonly found in human infections. What they discovered was that in 66 percent of the drains in 82 percent of the buildings, they detected at least one Fusarium biofilm that contained one of six sequence types of Fusarium that are associated with human infections.
In a news release issued by Penn State University, lead investigator Dylan Short states, "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. This strongly supports the hypothesis that plumbing-surface biofilms serve as reservoirs for human pathogenic fusaria."
The significance of this study is that it brings to light that people need to be aware of the hidden danger of fungi from common home fixtures that may literally kill them following an infection. In addition, this study opens a new window of research opportunities to understand microorganism biology and its impact on human contact within the home.
"Our apparently constant physical proximity to these fungi belies their relative obscurity in terms of public awareness and understanding by the scientific community," says David Geiser, professor of plant pathology and director of Penn State's Fusarium Research Center, which houses the world's largest collection of Fusarium.
"The species involved offer significant potential for studying host-microbe interactions, novel metabolic activities—including the production of mycotoxins and antibiotics—and the roles of microbes in indoor environments," he says.
Reference: Journal of Clinical Microbiology December 2011 vol. 49 no. 12 4264-4272