Antibiotics can cause the appearance of new harmful bacteria, according to a new study that suggests the way we often think about medicine should be revised. The findings show that antibiotics produce communities of beneficial bacteria, called biofilms, but can also independently and simultaneously induce potentially dangerous formations.
The scientists explain that that antibiotics can sometimes stimulate communities of bacteria to appear on surfaces and this was considered to be a side-effect. These biofilms can be beneficial, such as when they protect plant roots from pathogens, but the latest findigs suggest that bacteria may have evolved to produce in order to produce biofilms and not only for their killing abilities.
Biofilms can also harm, for instance when they form on medical catheters or feeding tubes in patients, causing disease, notes the study.
“It was never that surprising that many bacteria form biofilms in response to antibiotics: it helps them survive an attack. But it’s always been thought that this was a general stress response, a kind of non-specific side-effect of antibiotics. Our findings indicate that this isn’t true. We’ve discovered an antibiotic that very specifically activates biofilm formation, and does so in a way that has nothing to do with its ability to kill,” says Elizabeth Shank, an assistant professor at the University of North Carolina – Chapel Hill.
Shank and her team previously reported that the soil bacteria Bacillus cereus could stimulate one that is also found in the gastrointestinal tract of humans to form a biofilm in response to an unknown secreted signal. After they identified the signaling compound and modified its structure in order to eliminate the antibiotic activity and keep the biofilm production.
“That suggests that antibiotics can independently and simultaneously induce potentially dangerous biofilm formation in other bacteria and that these activities may be acting through specific signaling pathways,” said Shank. “It has generated further discussion about the evolution of antibiotic activity, and the fact that some antibiotics being used therapeutically may induce biofilm formation in a strong and specific way, which has broad implications for human health.”
The new study comes as more scientists express growing concerns that the long use of antibiotics are creating superbugs resistent to medicine.