New York City Mice Are Riddled With Dangerous, Drug-Resistant Bacteria, Study Finds

These bacteria, which include E. coli and salmonella, could pose a health hazard if the mice come into contact with people.

Close view of a tiny house mouse (Mus musculus).
Szasz-Fabian Jozsef / Shutterstok

These bacteria, which include E. coli and salmonella, could pose a health hazard if the mice come into contact with people.

The tiny rodents that hide away in the basements and pantries of New Yorkers, looking for a nice treat to nibble on, are packed with harmful bacteria that could get people sick, researchers of Columbia University have discovered.

The scientists published a report in the journal mBio detailing the types of dangerous bacteria one might be expected to pick up from the common house mouse (Mus musculus), with the goal of making people aware of the risks they could be facing.

The Columbia University team, led by Dr. Ian Lipkin, spent a year catching more than 400 mice in several locations in New York and testing their droppings for pathogens.

As per their findings, 37 percent of the rodents — collected from eight buildings in Manhattan, Brooklyn, Queens, and the Bronx — carried at least one bacterial pathogen.

The list of bacteria that can be found in New York City mice includes Escherichia coli, Shigella, Klebsiella pneumoniae, Salmonella enterica, and Clostridium difficile.

Some of these bacteria can cause life-threatening diseases, said Lipkin, who runs the university’s Center for Infection and Immunity.

For instance, E. coli is known to cause gastrointestinal symptoms and urinary tract infections, while salmonella can produce bacterial food poisoning, notes the Washington Post.

At the same time, Clostridium difficile is responsible for severe diarrhea in humans, and Klebsiella pneumoniae might give you pneumonia or bloodstream infections.

Alarmingly, the wide array of bacterial pathogens discovered in the droppings of New York mice has also shown signs of antimicrobial resistance, the study revealed.

These potentially dangerous bacteria were found to be drug-resistant in 23 percent of the rodents, reports the Washington Post.

According to the Wall Street Journal, the bacteria showed resistance to three common antibiotics.

“You not only have mice carrying bacteria that have the potential to cause human disease, but also carrying bacteria that have components that actually would thwart our ability to treat these infections with antibiotics,” Lipkin said in a statement for NPR.

Although the study didn’t establish a link between the pathogens found in New York mice and actual cases of bacterial infection in humans, Lipkin still advises caution.

“This doesn’t tell us that these mice are directly responsible for infecting humans. But they have the potential to do so.”

Lipkin strongly recommends that people avoid contact with the rodents by sealing up the holes used by mice to get into their homes. Moreover, he urges New Yorkers not to touch any food that has been near the animals’ droppings.

“There is no five-second rule,” Lipkin says. “If your food is contaminated with mouse droppings, you shouldn’t eat it.”

In addition to the drug-resistant bacteria, his team uncovered that the mouse droppings also tested positive for a large number of viruses, reports the New York Times.

The researchers published a separate study, featured in the same journal, describing 36 different types of viruses identified in the same mouse cohort. Among these viral pathogens, the team found six viruses that had never been seen before in common house mice.

The good news is none of these 36 viruses were linked to human disease, the study clarified.

Interestingly enough, the mice collected from the Manhattan neighborhood of Chelsea were fatter than the other rodents and also carried the largest number of viruses, notes the Wall Street Journal.