How Streptomyces Uses Iron to Target Competitor Bacteria

Researchers at Indiana University Bloomington have identified a new mechanism by which bacteria can eliminate their competitors within intricate microbial communities, highlighting innovative strategies to utilize viruses for targeting harmful bacteria.

The research was published in the journal Nature Microbiology. Zhiyu Zang, a graduate student in the Department of Chemistry at IU Bloomington's College of Arts and Sciences, is the first author, while J.P. Gerdt, an Assistant Professor of Chemistry at IU Bloomington, serves as the senior author.

It is been known for decades that bacteria compete with each other by synthesizing antibiotics and secreting them to kill their competitors so that they can invade their competitors’ space and get their nutrients. What we found here is that bacteria secrete molecules that take away the immune system of their competitor, using viruses already around as their own advantage.”

J.P. Gerdt, Assistant Professor and Study Senior Author, Indiana University

Bacteria are in a constant state of evolution to defend themselves against bacteriophages, which are viruses that infect bacteria. Understanding how bacteria can be infected is vital for human health, particularly since many bacteria play crucial roles in the production of food and medicine.

In their research, scientists studied two bacterial species: Streptomyces sp. and Bacillus subtilis. These two species are natural competitors and are commonly found in soil.

The researchers found that in a controlled environment containing bacteriophages, Streptomyces sp. compromised the immune response of Bacillus subtilis by releasing a metabolite called coelechelin. This natural product effectively sequestered iron from Bacillus subtilis, hindering its ability to defend itself against the surrounding bacteriophage attacks.

Gerdt suggests that such collaborative bacterial killing may influence the microbiomes both within and around us. If investigated further, combinations of phages and chemical agents like this could prove beneficial in treating antibiotic-resistant infections.

This research highlights that the chemicals around bacteria really matter. We have shown that the metabolites being produced by neighboring organisms can have a huge impact on how effective the immune system is.”

J.P. Gerdt, Assistant Professor and Study Senior Author, Indiana University