Phages drive the dissemination of antibiotic resistance genes by facilitating host adaptation to heavy metal stress

Summary

This multidisciplinary investigation reveals that soil bacteriophages significantly accelerate the horizontal dissemination of antibiotic resistance genes in paddy soils under heavy metal contamination. The mechanism operates through two pathways: phage-encoded metabolic genes that enhance bacterial survival and indirectly promote resistance gene transfer, and phage-encoded detoxification genes that directly facilitate metal resistance whilst simultaneously increasing membrane permeability to favour ARG mobilisation. The findings underscore the importance of incorporating phage dynamics into soil health and food safety risk assessments, particularly in regions where heavy metal and antibiotic resistance pressures coexist.

UK applicability

Whilst this research was conducted in Chinese paddy soils, the fundamental mechanisms of phage-mediated ARG dissemination under metal stress may be relevant to UK arable systems where both heavy metal accumulation (industrial legacy, biosolids application) and antibiotic resistance pose emerging concerns. UK soil monitoring and risk assessment frameworks could benefit from incorporating phage viromics alongside traditional microbial and chemical analyses, particularly in regions with legacy contamination or intensive agricultural practices.

Key measures

Metagenomic and viromics data characterising phage communities and ARG prevalence in paddy soils; abundance and co-occurrence of phage-encoded AMGs and HDGs with ARG fragments; bacterial survival and metabolic adaptation under heavy metal stress; ARG transduction rates following phage transplantation

Outcomes reported

The study identified two mechanisms by which soil phages promote antibiotic resistance gene (ARG) dissemination under heavy metal stress: phage-encoded auxiliary metabolic genes (AMGs) that reprogram bacterial metabolism and facilitate ARG cotransfer, and phage-encoded heavy metal detoxification genes (HDGs) that mediate metal detoxification whilst inducing membrane permeability changes that enhance ARG mobilisation. Phage transplantation experiments confirmed that elevated heavy metal stress triggers lysogenic phage-mediated ARG transduction to bacterial hosts.

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