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Temporal and spatial distribution of microbial community composition and antimicrobial resistance genes in tributaries of the Ohio River.
Citation:
Franklin, A., N. Brinkman, E. Wheaton, Rich Haugland, AND S. Keely. Temporal and spatial distribution of microbial community composition and antimicrobial resistance genes in tributaries of the Ohio River. American Society for Microbiology - Microbe, Washington DC, June 09 - 13, 2022.
Impact/Purpose:
Microorganisms play important aquatic ecosystem functions. Bacteria, specifically, help maintain and spread antimicrobial resistance, which is becoming a major health concern. Understanding how microbial communities and AMR vary over space and time is important for understanding water quality and possible impacts on human and animal health. This work analyzed microbial community and AMR data in six surface waters over one year showing that community composition and diversity as well as abundance of AMR varied spatially and temporally. This study demonstrated that to fully understand these parameters temporal and spatial analysis is necessary. Future studies should be designed to capture this variability to fully characterize microbial communities and AMR in surface waters.
Description:
Microorganisms play critical roles in aquatic ecosystems, such as cycling nutrients, capturing the sun’s energy via photosynthesis, and degradation of pollutants. Bacteria, specifically, play an important role in the maintenance and spread of antimicrobial resistance (AMR) in surface waters. Antimicrobial resistance has become a major public health concern, particularly for antimicrobial resistance genes (ARGs) that could impact human and animal health. A better understanding of the temporal and spatial dynamics of microbial communities, specifically bacteria, and AMR in aquatic environments is necessary to discern potential health risks. To determine the variability of microbial communities and AMR in surface waters, this study analyzed 16S rRNA sequence data, a suite of ARGs, an integron integrase (intI1), and four fecal indicators in water samples taken from six tributaries in the Ohio River basin over a one-year time frame. Based on microbial community analysis, each of the rivers had significantly different bacterial communities (p < 0.5), except for the three tributaries near large cities. The top two Phylum across the tributaries were frequently Proteobacteria (27-34% relative abundance) and Bacteroidetes (17-33% relative abundance). Other top Phyla included Cyanobacteria (10-17% relative abundance) and Actinobacteria (10-17% relative abundance). The dominant Phyla did shift by season with Cyanobacteria consistently dominant during summer (~55-85% relative abundance), and Bacteroidetes and Proteobacteria having higher abundances in the winter and spring/fall, respectively. Microbial community diversity within each river varied temporally with lowest diversity typically in the summer, likely due to the dominance of Cyanobacteria. The abundance of ARGs, intI1, and fecal indicators varied throughout the year with ARGs and IntI1 peaking in the fall and spring. IntI1 and sul1 were strongly correlated in every tributary. Abundances of ARGs and intI1 were correlated with fecal indicators indicating that human and/or agricultural pollution may play a role in their presence. Increased microbial diversity (inverse simpson) and species richness (SOBS) were often associated with the presence of ARGs, intI1, and fecal indicators. Overall, this work demonstrates that bacterial communities and AMR in surface waters can vary significantly over time and by geographic region, which adds to our overall understanding of microbial communities and AMR in aquatic systems and the potential risks to human and/or animal health.
