The Study Found That Bathroom Floor Drains Are A Breeding Ground For Drug-resistant Bacteria

A small study in Germany found that antibiotic-resistant bacteria were present in more than three-quarters of households, and in particular in floor drains.

Drug-resistant bacteria are commonly found in hospitals and crowded places such as trains and shopping centres, but little is known about their presence in homes.

To find out, Deerke Borkemir and colleagues at Rhein-Waal University of Applied Sciences in Germany took samples of floor drains, dishwashers and washing machines from 54 private homes.

They found antibiotic-resistant bacteria in 82 percent of homes, mostly in floor drains, the report said. DNA analysis showed that there were twice as many antibiotic-resistant genes in floor drains as in dishwashers and 400 times as many in washing machines.

Berkemere says floor drains are a hotbed for bacteria because they are warm and moist and have a steady supply of nutrients, including dead skin cells and other organic matter shed from the body. He says bacteria in floor drains have developed antibiotic resistance from repeated exposure to antibacterial ingredients in soaps and cleaning products.

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The majority of antibiotic-resistant bacteria in floor drains are environmental bacteria that do not normally infect humans, but a small number have clinical significance, including multidrug-resistant E. coli, which can cause urinary tract infections, and multidrug-resistant Pseudomonas aeruginosa, which can cause pneumonia, the report said.

Assuming the findings reflect the high prevalence of antibiotic-resistant bacteria in many households around the world, people should not be too worried, “especially given how often we may come into contact with antibiotic-resistant bacteria in our daily lives,” Dr. Borkemir said. But he said people more susceptible to infection — such as pregnant women and the elderly — should avoid exposure to floor drains.

In addition to the potential risk of infection within the home, Antibiotic-resistant bacteria can enter the wastewater system through sewers and spread into the broader environment, Dr. Borkemir said. His team is now studying the spread of antibiotic-resistant bacteria in household sewers.