The article addresses the growing health concern of antibiotic resistance (AR), primarily stemming from the misuse and overuse of antibiotics in medicine and agriculture, promoting the spread of antibiotic resistance genes (ARGs) through horizontal gene transfer among bacteria. It emphasizes that fecal contamination, particularly from wastewater treatment plants and agricultural runoff, is a significant source of ARGs in the environment.
The focus of the study is periphyton—complex communities of microorganisms in freshwater biofilms—that serve as hotspots for AR transmission. The study uniquely employs long-read sequencing technology to characterize the microbiome and resistome of periphyton collected from various sites over a year in central Ohio, aiming to evaluate the clinical relevance and transmissibility of ARGs.
Findings show substantial ARG diversity, with 88 unique ARGs from 17 antibiotic classes primarily related to multidrug resistance. The microbial composition was dominated by Proteobacteria, and key hosts of ARGs included Escherichia and Pseudomonas. Seasonal and locational shifts were noted in microbiome composition, with upstream sites showing lower levels of fecal-associated bacteria compared to downstream urban areas, indicating the impact of urbanization on freshwater microbiomes.
Importantly, the study suggests that while periphyton contribute to the overall environmental burden of AR due to their diversity and mobile genetic elements, they may not be significant reservoirs of clinically relevant ARGs in pathogenic hosts. The findings reinforce the need for environmental considerations in addressing the global public health crisis of AR through a One Health framework.
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