Pesky flies buzzing around your home may be carrying antibiotic-resistant bacteria that can also be found in waste, according to a recent study by Kansas State University, published in the Applied and Environmental Microbiology journal.

Insects like the house fly carry antibiotic-resistant bacteria from one point to another, including from food animal farms and wastewater treatment facilities, for example, to urban areas.

"There are a number of insects that are commonly associated with animals, such as house flies and cockroaches," Ludek Zurek, professor of microbial ecology and lead author, said in a statement. "House flies are common where animal manure is produced, including in cattle, poultry and swine operations. Cockroaches, primarily German cockroaches, have become a common pest in confined swine operations."

According to a 2013 report by the Centers for Disease Control and Prevention, at least 2 million people become infected with antibiotic-resistant bacteria, and at least 23,000 people die each year as a direct result of these infections in the United States.

Antibiotics are most widely used at hospitals and food animal production facilities.

Zurek and his colleagues analyzed bacteria from the digestive tracts of house flies and cockroaches collected from the aforementioned waste sites.

"We found these insects carry the same bacteria found in the animal manure," Zurek said. "Then we started sampling insects found in surrounding urban areas, including fast food restaurants, and again, we found house flies with multi-drug resistant bacteria."

House flies found in urban areas further from these waste treatment sites had fewer antibiotic-resistance bacteria than flies on-site, but fact is it they still had traces of it. And these little guys like to get around.

"Cockroaches and house flies are highly mobile, and they are attracted to residential areas," Zurek added. "They are attracted to our food and drinks. They have great potential to move multi-drug resistant bacteria to urban areas."

And insects are not the only source of the problem. Zurek's team found that wild birds, such as ravens and crows, carry multi-drug antibiotic-resistant bacteria.