Microbiome ecology and antibiotic treatment failure: resistance spread, microbial competition and community engineering.

The failure of antibiotic treatment is a growing concern, driven in large part by the rising incidence of antimicrobial resistance (AMR). Increasing evidence points to the importance of microbial competition in preventing the colonization of disease-causing pathogens and the spread of AMR. Crucially, the pathogens we target with antibiotics do not exist in isolation but instead compete and interact with the microbial communities that colonize the human body, microbiomes. Here, we therefore argue that the key to approaching the challenge of antibiotic treatment failure is understanding the strategies and mechanisms that microbes use to succeed in microbiomes. We discuss how microbial competition influences the colonization of pathogens and the spread of resistance via horizontal gene transfer. We then discuss how microbial competition may be used to synergize with antibiotic treatment or even replace it. Overall, we argue that studying microbial interactions offers a powerful approach to understanding and even mitigating antibiotic treatment failure.