Living in the city toughens up bird microbes

To figure out how bird behavior and ecology might affect pathogen spread, researchers collected 700 genomes from Campylobacter jejuni—a bacterium that causes diarrheal illness in people—from the poop of 30 different bird species in eight countries. They were looking for genetic variations that suggest antimicrobial resistance. The birds differed in body mass, clutch size, habitats, diets, social organization, and proximity to people—factors that might affect how likely each species is to transmit pathogens.

They found that birds like crows, seagulls, and pigeons that are well-adapted to urban areas had more C. jejuni genotypes and three times the number of resistance genes. Aquatic birds like ducks and geese also had more resistant microbes, likely from exposure to wastewater contaminated with antibiotics and antivirals like Tamiflu.

The results suggest that proximity to humans increases pathogen diversity and promotes resistant strains—which isn’t great news, given that urban life continues to encroach on the slivers of wild space remaining. “We need to ensure we do not lose sight of our role in creating these problems in the first place and resist the temptation to cast the blame on wildlife,” said microbial ecologist Katherine Lagerstrom, who was not involved in the work.”