Gut microbiome communities show resilience to drugs through cross-protection, study reveals

New Delhi: New research from EMBL Heidelberg has revealed that bacteria in the gut microbiome are more resilient to drugs when they form communities. The study, the first of its kind, compared the effects of 30 diverse drug treatments on bacteria grown in isolation versus those in a complex microbial community.

The findings, recently published in Cell, show that the drugs had a less pronounced impact on bacteria when they were part of a community, thanks to cross-protection mechanisms.

Researchers investigated how different drugs, targeting both infectious and non-infectious diseases, affected 32 bacterial species representative of the human gut microbiome. They discovered that when bacteria are in a community, certain drug-resistant species exhibit behaviors that protect more sensitive bacteria. This “cross-protection” allows bacteria that would normally be vulnerable to a drug when isolated to survive and grow normally in the presence of that same drug when in a community setting.

Researchers included EMBL Heidelberg’s Typas, Bork, Zimmermann, and Savitski groups, along with several alumni including Kiran Patil (MRC Toxicology Unit, Cambridge, UK), Sarela Garcia-Santamarina (ITQB, Portugal), André Mateus (Umeå University, Sweden), Lisa Maier, and Ana Rita Brochado (University Tübingen, Germany), compared a large number of drug-microbiome interactions.

Co-first author Sarela Garcia-Santamarina, now a group leader at ITQB in Portugal, expressed “We were not expecting so much resilience. It was very surprising to see that in up to half of the cases where a bacterial species was affected by the drug when grown alone, it remained unaffected in the community.” The team identified two key mechanisms—bioaccumulation and biotransformation—whereby bacteria either take up or break down drugs to protect other species, explained Michael Kuhn, Research Staff Scientist in the Bork Group.

Despite this resilience, the study also uncovered limits to the community’s protective capacity. At high drug concentrations, the cross-protection strategy gave way to “cross-sensitisation,” a phenomenon where even drug-resistant bacteria became sensitive to drugs when in a community. This finding underscores that while low drug concentrations allow microbiome communities to remain robust, higher concentrations disrupt the protective balance and increase bacterial vulnerability.

Lead author Nassos Typas, an EMBL group leader, highlighted the implications of these findings, suggesting that further research into cross-sensitisation mechanisms could help explain how microbiome communities collapse under drug pressure. 

In a collective approach much like the bacteria they studied, the researchers combined their scientific strengths to explore the interactions between bacteria and drugs. The Typas Group contributed their expertise in high-throughput experimental microbiome and microbiology techniques, while the Bork Group provided bioinformatics insights. The Zimmermann Group led metabolomics studies, and the Savitski Group handled proteomics experiments. External collaborators also played a key role, with EMBL alumnus Kiran Patil’s group at the Medical Research Council Toxicology Unit, University of Cambridge, offering expertise in gut bacterial interactions and microbial ecology.

Moving forward, the researchers hope to use their insights to develop synthetic microbiome communities capable of withstanding drug treatments without losing their composition. This could ultimately help tailor medical prescriptions to minimize the side effects of drugs on the gut microbiome. 

Peer Bork, a director at EMBL Heidelberg and co-author of the study, emphasized the potential of these findings to advance our understanding of drug-microbiome interactions, paving the way for more precise and effective treatments in the future. “This study is a stepping stone towards understanding how medications affect our gut microbiome. In the future, we might be able to use this knowledge to tailor prescriptions to reduce drug side effects.”

Kiran Patil, MRC Toxicology Unit Cambridge, UK, added, “Towards this goal, we are also studying how interspecies interactions are shaped by nutrients so that we can create even better models for understanding the interactions between bacteria, drugs, and the human host.”