Study finds NYC mice are hotbeds of antibiotic-resistant bacteria

  • Researchers at Columbia University tested dropping from mice in 6 residential buildings of New York City
  • They found antibiotic-resistant bacteria that could infect humans in all areas
  • The most viruses were found in mice from Chelsea; those mice were heavier 

New York City house mice carry antibiotic-resistant bacteria that has caused life-threatening gastroenteritis in people, a new study warns.

While rats are pitted as the demons of New York, researchers at Columbia University warn mice are the real health danger for humans.

Apartment-dwelling rodents all over the city carry treatment-resistant C. difficile, E. coli, Shigella and Salmonella that can be transmitted to residents, the team found.

Mice from homes in the affluent borough of Chelsea carried the most risky viruses, the study revealed.

Experts warn the findings, published today, reveal another line of attack as we fight to stave off antibiotic resistance. It should also, they said, prompt New Yorkers to ease off their hatred of rats and focus on the smaller disease vessels closer to home.

Researchers found apartment-dwelling rodents all over New York City carry treatment-resistant C. difficile, E. coli, Shigella and Salmonella that can be transmitted to residents

‘From tiny studios to penthouse suites, New York City apartments are continually invaded by house mice,’ said lead author Simon H. Williams, BSc, a research scientist at the Center for Infection and Immunity.

‘Our study raises the possibility that serious infections – including those resistant to antibiotics – may be passed from these mice to humans, although further research is needed to understand how often this happens, if at all.’

The researchers collected 416 mice from residential buildings at seven sites across New York City over a period of one year. 

They performed a genetic analysis of their feces, and found that the mice carried a number of bacteria, including C. difficile, E. coli, Shigella, as well as Salmonella.  

Crucially, they found evidence of genes that encourage resistance to common antibiotics.

The Salmonella connection to animal waste is nothing new – millions of Americans contract the food poisoning condition every year and it is often traced back to mice. However, the researchers said the sheer scale of Salmonella in New York City mice was startling. 

C. difficile infections, meanwhile, are most commonly contracted from bacteria in hospitals, and yet this study emphasized how much it could also be spread in the by the mice in homes.

Alongside that study, the team also published an analysis which took a closer look at the viruses found in the mice droppings.

They found 36 viruses, including six new viruses, none of which are known to infect humans. 

But they also found genetic sequences matching viruses that infect dogs, chickens, and pigs. This showed that it’s possibile that some of the viruses have crossed over from other species. 

Mice from Chelsea, heavier than mice from other sites, also carried more viruses. 

‘New Yorkers tend to focus on rats because they are larger and we see them scurrying around in streets or subways,’ says senior author W. Ian Lipkin, John Snow Professor of Epidemiology, and director of CII.

‘However, from a public health vantage point, mice are more worrisome because they live indoors and are more likely to contaminate our environment, even if we don’t see them.’