Lake Katherine study conceptual diagram
Antibiotic resistance genes (ARGs) in suburban freshwater ecosystems pose a growing public health concern by potentially reducing the effectiveness of medical treatments. This study investigated how rainfall influences ARG dynamics in Lake Katherine, a 62-hectare suburban lake in Columbia, South Carolina, over one year. Surface water was collected under both dry and post-rain conditions from three locations, and ARGs were identified using metagenomic sequencing. Statistical models revealed that six of nine ARG classes with sufficient data showed significant responses to rainfall. Three classes, Bacitracin, Aminoglycoside, and Unclassified, were more abundant after rainfall, while Tetracycline, Multidrug, and Peptide resistance genes declined. Taxonomic analysis showed that members of the Pseudomonadota phylum, especially Betaproteobacteria, were prevalent among ARG-carrying microbes. These findings suggest that rainfall can alter the distribution of ARGs in suburban lakes, highlighting the importance of routine monitoring and water management strategies to limit the environmental spread of antibiotic resistance.
Rainfall-associated changes in ARG-class abundance
Site-specific associations between rainfall and ARG class abundance in Lake Katherine. Rainfall-associated changes in ARG-class abundance: (A) average trends for the lake across all sites; (B) Site 1; (C) Site 2; (D) Site 3. All figures share an x axis and a y axis for comparability. X axis is the expected percent change in the ARG class per cm of rain in the 2 days leading up to the sampling date. Y axis is the baseline RPKM for the ARG class at 0 cm of rainfall in the two days leading up to the sampling. Significance is based on the X axis, because the primary focus is on whether rainfall has a significant impact on the ARG classes listed. Significance: Brown (<0.001), Red (<0.01), Pink (<0.05), Blue (>0.05).