World.- Researchers from the Pompeu Fabra University of Barcelona have shown in a study that the response of bacteria to antibiotics may depend on other species of bacteria with which they live.
The study, published today in the journal Science Advances, may affect the treatment of bacterial infections as it suggests new strategies to fight these pathogens. Since the discovery of penicillin nearly 90 years ago, antibiotics have saved millions of lives. Currently, the concentration of each antibiotic needed to eliminate a wide variety of bacterial species is known in detail.
These tests are usually done in crops where each species of bacteria lives on its own. However, often in infections we do not find a single species of bacteria, but live together multiple of them that can interact, sharing all kinds of chemical signals.
In addition, our body contains a lot of beneficial bacteria (the microbiota), with which pathogens can live together as well. That’s why, in this study, researchers have raised how communities with multiple species of bacteria respond jointly to antibiotics, the authors say.
To address this question, the team has studied how Bacillus subtilis and Escherichia coli bacteria responded to the antibiotic ampicillin. Alone, E. coli is sensitive to this antibiotic – from a certain concentration it cannot grow – and B. subtilis is tolerant and manages to grow.
Letícia Galera-Laporta, first author of the study, explains that «in a counterintuitive way, we observe that when the two species of bacteria coexist, their response to the antibiotic is opposite to when they are alone. The bacteria that could survive die and the other way around.»