Men's offices have more bacteria, study finds

But not all offices are equally populated: Men's spaces were found to harbor more microbe species than women's.

In developed countries, millions of people spend about 90 percent of their time indoors-most of them working eight or more hours without going outside, according to the study.

Increasingly, "this is the human habitat, and I think it's important to know what is in our human habitat and where it comes from," said study co-author Scott Kelley , a biologist at San Diego State University, Kazinform cites National Geographic.

"Since humans are the main source of the bacteria in offices, we are the ones constantly spreading contamination around our environments," Kelley said.

"Normally this is not a problem. However, in places like hospitals and nursing homes, even harmless bacteria can be a problem."

Kelley and colleagues chose three climatically diverse cities-New York City , San Francisco , and Tucson, Arizona -and took swabs from various office surfaces in 30 offices in each city.

To find out "who and what" was there, the scientists cultured-or grew-the sampled bacteria in the lab, as well as analyzed their DNA, Kelley said.

The team found the bacterial communities of New York and San Francisco were "indistinguishable," mostly because the bacteria come from common species that live on people, Kelley noted.

Microbes regularly fall from skin and settle on office surfaces. "I was a bit surprised how much was out there and how much we were contributing to this environment. It's not just blowing in through dust-we're constantly sort of shedding it," Kelley said.

Tucson had different species from New York and San Francisco, likely due to bacteria species adapted to the desert soils in the region, he said.

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