Assessing the Ecological Roles of Resistomes within Microbial Communities in Antibiotic-contaminated Ecosystems

The role of antimicrobial resistance genes (ARGs) in ecosystem sustainability, particularly in ecosystems under antibiotic pollution, remains underexplored. These genes exist even in environments free from antibiotic contamination, highlighting their potential ecological roles. For example, what roles do ARGs play in stabilizing microbial communities under stress, particularly due to antibiotics, with respect to microbial diversity and functions, including nutrient cycling and organic matter decomposition? This review studied the interconnections between ARGs and microbial communities, looking at how the abundance of resistomes affected microbial diversity and how that diversity influenced resistome profiles, ecosystem functions, and community resilience. The studies indicated that higher microbial diversity may be associated with an increase in ARG abundance in competitive environments (such as agricultural soils, p < 0.01), while systems with lower diversity (like intensive livestock farms) show 2–3 times greater levels of clinically significant ARGs (aadA2, tetA). The presence of sub-inhibitory concentrations of antibiotics (e.g., 5 mg·L⁻¹ tetracycline) enhances ARG spread by 3.20 times through horizontal gene transfer, while higher concentrations (> MIC) lead to a 61.2% reduction in microbial biomass but favor the persistence of resistant taxa (for example, Pseudomonas spp). Importantly, resistomes are potentially ecological tools: communities carrying ARGs have been shown in some studies to maintain greater functional stability (such as nutrient cycling) when under antibiotic stress. In benthic sediments, ARGs serve as a metabolic reservoir that supports microbial persistence. ARGs function as both ecological mechanisms that promote microbial resilience and clinical risks that drive antibiotic resistance. Therefore, the role of ARGs in promoting microbial survival must be carefully weighed against the public health hazards of their global dissemination.