New review reveals how microbial communities accelerate the global spread of antibiotic resistance

A new scientific review has uncovered how complex microbial communities, including those in the human gut and the natural environment, act as powerful engines that drive the evolution and spread of antimicrobial resistance. The findings highlight urgent risks to global health and call for coordinated action across human, animal, and environmental sectors.

The research team synthesized evidence from microbiology, ecology, and environmental science to explain why antimicrobial resistance evolves differently in diverse microbial ecosystems compared with individual bacterial species. These ecosystems include the gut microbiome, wastewater networks, soils, and natural water bodies, all of which contain thousands of interacting species.

“Microbial communities are far more than random collections of bacteria,” said corresponding author Jianhua Guo. “They are dynamic ecosystems with constant competition, cooperation, and genetic exchange. These interactions create ideal conditions for antimicrobial resistance to emerge and spread.”

Antimicrobial resistance causes millions of deaths every year and continues to rise as bacteria acquire new resistance genes. The review describes how five major pathways of horizontal gene transfer enable bacteria to exchange resistance genes within communities. These pathways include plasmid mediated conjugation, transformation of free DNA, bacteriophage mediated transduction, extracellular vesicles that carry genetic material, and protozoan predation that concentrates bacteria inside protective vacuoles.

The authors explain that microbial communities amplify the efficiency of these processes. High population density creates more opportunities for cell to cell contact. Biofilms protect bacteria from antibiotics, allowing resistant strains to thrive. Cooperative behaviours such as antibiotic detoxification by neighbouring species can shield sensitive bacteria, enabling them to survive drug treatment and later acquire resistance genes.

The review also highlights the surprising role of protozoa in natural environments. These microbial predators can engulf bacteria and create enclosed spaces that promote genetic exchange. Some protozoa even expel packages of undigested bacteria that remain protected from antibiotics, which helps resistance spread further.

“Microbial predators and their prey have a long evolutionary history,” Guo said. “Our review shows that these interactions unintentionally create safe zones where bacteria can share resistance genes and become harder to kill. This makes antimicrobial resistance a true ecological problem that extends beyond hospitals.”

The authors frame these findings within the One Health perspective. Resistant bacteria and genes move freely among humans, animals, and environmental reservoirs. Wastewater discharge releases resistance genes into rivers and soils. Agricultural antibiotic use enriches livestock microbiomes and increases spillover into the food chain. Global travel accelerates the international spread of resistant strains.

Clinical settings remain major hotspots for antimicrobial resistance evolution. Patients on intensive antibiotics often carry mixed microbial populations that exchange genetic material. Biofilms on medical devices and drainage systems act as long term reservoirs. According to the review, these factors contribute to the rise of resistant pathogens that cause pneumonia, bloodstream infections, urinary tract infections, and other life threatening illnesses.

The authors conclude that understanding antimicrobial resistance within microbial communities is essential for predicting future risks and designing effective interventions. They recommend integrated surveillance, reduction of unnecessary antibiotic use, and improved management of waste and water systems.

“Microbial communities shape the future of antimicrobial resistance,” Guo said. “If we want to protect public health, we must consider the entire ecosystem rather than individual pathogens.”

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Journal reference: Yu Z, Gillings M, Ashbolt NJ, Guo J. 2025. Antimicrobial resistance in complex microbiomes: ecological evolution and public health risks. Biocontaminant 1: e011  

https://www.maxapress.com/article/doi/10.48130/biocontam-0025-0008 

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About Biocontaminant:
Biocontaminant is a multidisciplinary platform dedicated to advancing fundamental and applied research on biological contaminants across diverse environments and systems. The journal serves as an innovative, efficient, and professional forum for global researchers to disseminate findings in this rapidly evolving field.

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