A new study published in Environmental Microbiology has found that antibiotic resistant bacteria are showing up in crows. This is disturbing, because human-derived drug resistant bacteria should not be in wildlife.
The birds harbored vancomycin-resistant enterococci (VRE) that were not naturally derived; that is, the bacteria came from a human source. Scientists found the bacteria in 2.5% of crows sampled across the U.S.
Vancomycin is a last-resort antibiotic used to treat staphylococcus infections in people. And the vancomycin resistant gene is very rare. Scientists think that the birds may have acquired the bacteria from wastewater or dumpsters. And since crows migrate, the antibiotic-resistant bacteria can be spread over large areas. The bacteria are shed in feces.
Bird droppings contain many different types of bacteria, along with yeasts and fungi. Many of those pathogens can become airborne as the bird releases them; humans can get sick just being in the same area as bird droppings. Diseases that can be carried through bird poop include histoplasmosis from a fungus, candidiasis, which is a yeast or fungus infection, salmonellosis, E. coli O157:H7, and St. Louis Encephalitis.
The problem with VRE is that if humans can acquire it from bird poop; the infection will be resistant to treatment. Wild birds travel far and wide, and since antibiotic-resistant bacteria can swap genes with other bacteria, the birds are a very efficient vector for the bacteria to use to spread. Antibiotic resistant bacteria can also be more virulent and outcompete other bacteria.
In the United States, 2 million people become sick with antibiotic-resistant bacterial illnesses every year; 23,000 of those people die. And drug resistant infections are increasing. Scientists don’t know how this new development will affect human health. But it’s not encouraging.
