We May Be Able to Outsmart Superbugs Using Their Own Defenses

Antibiotic-resistant superbugs are a looming menace to medicine, and now, some strains have evolved to eat the very compounds that try to kill them. Fortunately, a microbiologist may have discovered a way to use those very same microbes to devise new antibiotic approaches.

Penicillin itself is derived from a microbe called Penicillium, pictured here under the microscope. In nature, Penicillium is somewhat of a bully, using antibiotic to kill-off competitors for food and resources.

Although most drug-eating microbes aren’t disease-causing per say, Gautam Dantas, a microbiologist at Washington University in St. Louis and the lead author of a new study, recognized that shared strategies in antibiotic-resistant bugs could give us some innovative approaches to the ongoing superbugs arms race.

By screening soil microbiomes for penicillin-degrading tools, researchers identified a cohort of compounds microbes use to neutralize antibiotic threats. Researcher Xiaohui Zhao from Univesity of Connecticut says that because there are patterns in how the enzymes cut antibiotics, this research could inform the design of new antibiotics. “Now that we understand which enzymes the bacteria use to disable the antibiotic, we can develop defense strategies and fight back,” Terrence Crofts, a postdoc who works with Dantas, wrote in The Conversation.

Another approach would be treating new antibiotics with the enzyme, to examine whether new antibiotics could prevail in microbes who generally eat antibiotics. Additionally, by identifying crucial antibiotic-resistance components for example, scientists could devise ways to turn off antibiotic-eating enzymes in superbugs—ultimately stripping superbugs of their super-powers.

But new antibiotics may not be the only way these microbes can help combat resistance. Since medical waste often contains large quantities of antibiotics, it’s common for microbes cohabiting with medical waste to develop antibiotic resistance. Intercepting the cycle, by preemptively neutralizing antibiotic waste with enzyme, could prevent disease-causing germs from spontaneously developing resistance in the waste environment.

We wouldn’t have to add antibiotic-eating bacteria to the waste, either—just the enzymes themselves. Still, it wouldn’t be easy. Here’s Shawna Williams, reporting for The Scientist:

The idea is “very ambitious,” but such a system would likely be too expensive to make significant headway on cleaning up antibiotics in the environment, says Julian Davies, a microbiologist at the University of British Columbia in Vancouver who was not involved in the study.

Although it would cut costs, using microbes for enzyme factories is potentially risky, too, given that we’d be intentionally introducing antibiotic-resistant critters into the environment. In this case, the risk could be resistant microbes popping up in unexpected places—potentially neutralizing antibiotics in contexts where we’d still want antibiotics to work. In the future, this risk could be mitigated with a control kill-switch, but for now, directly applying just the enzyme may be the safest option.

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