Some bacteria can use the antibiotic penicillin as food. How they do this is revealed in a study published online this week in Nature Chemical Biology. Understanding how these microbes thrive in the presence of penicillin could help to combat the spread of dangerous antibiotic-resistant strains. Microbes that survive in the presence of antibiotics, such as those found in contaminated soil, may spread and threaten the health of humans and animals. Some bacteria take this ability a step further, and can actually use antibiotics as sustenance.

Gautam Dantas and colleagues identify the enzymes and genes that allow some soil-dwelling bacteria to break down penicillin into parts that they can use. The authors find that these bacteria first inactivate penicillin by using the enzyme β-lactamase-a common strategy among resistant bacterial strains. These antibiotic-eating bacteria, however, also have special enzymes, newly discovered in this study, that further break down the inactivated penicillin into pieces that can be used as fuel.

The authors conclude that the enzymes and genes identified in this study could be used to synthesize new antibiotics, to remediate antibiotic-contaminated soil, and to detect spreading resistance early.