Drug Resistance on Steroids: Microbes That Eat Antibiotics

New research appearing in this week’s edition of Science focuses on a wide variety of bacteria that have not simply evolved resistance to antibiotics, but can in fact survive entirely on a diet of compounds intended to kill them. Given increasing concerns about the threat of drug-resistant staph infections in healthcare centers and the risks of pumping antibiotics into feedlot animals, this latest study could help shape public health guidelines for antibiotic use.

Mitch Leslie reports on the study, Bacteria Subsisting on Antibiotics, in Science’s News of the Week (subscription):

Eighty years after Alexander Fleming discovered penicillin on a moldy culture dish, the battle against killer bugs is faltering. More and more bacteria–including insidious tuberculosis strains that have cropped up (Science, 15 February, p. 894)–now shrug off almost all antibiotics. Meanwhile, few new antibiotics are reaching the clinic. Medicine is on the defensive, says microbiologist and physician Stuart Levy of Tufts University School of Medicine in Boston. “We are not keeping up with the bacteria.”

Geneticist George Church of Harvard Medical School in Boston and colleagues had not planned to dig up more grim news about antibiotics. These researchers were hunting for microbes that could convert agricultural waste into biofuels and were using antibiotics in their control studies. But for some bacteria, they learned, antibiotics provide a meal.

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The medical importance of these consumers is also unknown. In principle, the germs could cause trouble in two ways, says Wright. Microbes that are usually innocuous might pick on people, such as AIDS patients, who have crippled immune systems. Moreover, soil bacteria pass around resistance-conferring genes like teenagers swap downloaded music files, and pathogenic bacteria could likewise pick up antibiotic-digesting genes, particularly from a closely related microbe.

Ed Yong at Not Exactly Rocket Science explains the risk that the abilities of these diverse bacteria could migrate to other species:

The real danger is that the soil-living species could provide new defenses that more dangerous ones can draw on to shrug off our best drugs. Bacteria are capable of passing genetic material between one another as easily as two humans might swap business cards, making it trivial for the soil super-bugs to pass their crucial genes on to more dangerous species.

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In principle, bacteria should be more able to successfully take up resistance genes from other closely related species. It’s worrying then that [lead author] Dantas’s antibiotic-eaters belonged to such diverse groups.

Antibiotics save lives; ensuring that they remain effective into the future is a crucial matter of public health policy.

Tags: public health

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