Medicine

Study finds pathogenic bacteria, resistance genes in apartment mice

Study finds pathogenic bacteria, resistance genes in apartment mice

Mice in New York City carry disease-causing bacteria, some of which may be resistant to antibiotics, according to the study.

Overall, the researchers found that more than a third of the mice carried at least one potentially pathogenic bacterium, while about a quarter of them had bacteria with at least one resistance gene.

House mice don't carry door keys, but they can freely enter any residence in New York City, from low-rent studios to penthouse suites.

Researchers emphasized that more study is needed before they could definitively say that serious and antibiotic-resistant infections could be passed from mice to people.

It would be almost impossible to conduct research directly linking a mouse pathogen with a human disease, said Charles Calisher, a professor emeritus at Colorado State University, who was not involved in the new studies.

"A report commissioned by the British government estimates that antibiotic-resistant bacteria will kill 10 million people per year by the year 2050, so coming up with new methods to generate antimicrobials is of huge interest, both from a scientific perspective and also from a global health perspective", de la Fuente-Nunez says.

The mice appeared to be healthy, and Dr. Lipkin said he presumes that they are carriers of the bacteria but are not affected by them. None of the detected viruses, including the newly discovered ones, were known to cause human diseases.

The microbiome of wild Mus musculus (house mouse), a globally distributed invasive pest that resides in close contact with humans in urban centers, is largely unexplored.

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The study, published Tuesday, involved 416 mice collected from residential buildings at seven locations in the five boroughs.

Although the study didn't establish a link between the pathogens found in NY mice and actual cases of bacterial infection in humans, Lipkin still advises caution. Running genetic tests, the researchers defined 235 separate genera and 149 distinct species of bacteria, including the most common causes of gastrointestinal upset: C. difficile, E. coli, Shigella and Salmonella. "We know animals, including pets, food animals and wildlife, can carry a wide range of resistant bacteria".

Therefore, humans exposed to infected mice - through direct contact, droppings or urine - would have a hard time killing the germs, which means any potential illnesses contracted from the rodents could turn deadly.

Antibiotic resistance is a prominent issue regarding animals.

Lipkin said while they haven't proven mice are responsible for transmitting disease to humans, he recommends exercising caution.

"I wouldn't think of mice in your house as Stuart Little", says Lipkin, who served as chief scientific consultant on the movie Contagion. "That's the normal state of animals, and it's true of humans as well, and the vast majority of these bacteria and viruses are harmless".

Yet it was clear from the new report that bacteria have traveled between species, Lipkin said.

This research is particularly important to do in New York, Dr. Daszak said, because the city is a destination for people from all corners of the world.