Antibiotic-resistance is a major concern with far-reaching effects. Bacteria that can shrug off the drugs meant to kill them pop up all over the world — in ancient feces, in isolated cultures of people who have never taken antibiotics, and even in the Hudson River. Now researchers have found such microbes in African wildlife, reports Jennifer Balmer for Science.

Two researchers, Sarah Elizabeth Jobbins and Kathleen Ann Alexander, tested Escherichia coli strains for resistance to 10 commonly used antibiotics, they report in the Journal of Wildlife Diseases. More than 40 percent of the animals tested — including hyena, crocodile, leopard, bushbuck, giraffe and baboon — carried E. coli resistant to one antibiotic and more than 13 percent were resistant to three or more. More than 94 percent of humans tested carried strains resistant to one antibiotic and nearly 69 percent were resistant to three or more antibiotics. The implication is that the relationship isn’t coincidental.

The resistance may have traveled through water contaminated with human fecal matter via sewage and stormwater runoff, the researchers write. The water-dwelling animals had higher levels of antibiotic resistance than those that lived on land.

"Alarmingly, we demonstrated widespread resistance in wildlife to several first-line antimicrobials used in human medicine—ampicillin, doxycycline, streptomycin, tetracycline, and trimethoprim– sulfamethoxazole (commonly known as cotrimoxazole)," the researchers write. Doxycycline, they note, is often used by visitors to Africa to protect against malaria. Cotrimoxazole is given to HIV patients to protect against infection. Widespread resistance to those drugs may someday render them useless as medicine.

Already, experts know antibiotic resistance is in the food supply. But this study shows there are other ways it can spread, explains Alexander in a press release. She says, " In an environment where there are no commercial agriculture or livestock production activities, our next step is to establish why we are seeing these patterns."