African wildlife harbors resistance to first-line antibiotics

K. A. Alexander

African wildlife harbors resistance to first-line antibiotics

The emergence of drug-resistant microbes—such as tuberculosis and methicillin-resistant Staphylococcus aureus—is a growing threat to public health worldwide. Although many studies have documented antibiotic-resistant bacteria in wild animals, how these microbes arise—and whether they can be transmitted to humans—is poorly understood. Drug resistance in wildlife can develop on its own, but it can also be accelerated by exposure to human waste or agricultural runoff with traces of antibiotics. Now, a new study finds a wide variety of African wildlife harbor drug-resistant microbes that are similar to those found in humans living in nearby villages. In 2011, researchers collected 150 fecal samples from 18 wildlife species and 200 samples from humans in northern Botswana and tested them for antibiotic-resistant strains of the common intestinal bacteria Escherichia coli. They measured resistance against 10 widely used first-line antibiotics, including those used to prevent and treat diseases like malaria and tuberculosis. The team found that more than 40% of wildlife—which included leopards, elephants, and crocodiles—and 90% of humans harbored E. coli resistant to at least one antibiotic, they report this month in the Journal of Wildlife Diseases. Further, more than 10% of animals and 70% of humans were resistant to three or more first-line antibiotics. Human and wildlife E. coli isolates also had similar levels of resistance to the same antibiotics—most commonly ampicillin, doxycycline, streptomycin, tetracycline, and trimethoprim/sulfamethoxazole. Multidrug resistance was most common in aquatic animals and in those animals living near crowded villages. Researchers still can’t say for certain what the relationship is between human and animal resistance, but in this case they suspect a waterborne connection.