AUTHOR=Bourdonnais Erwan , Colcanap Darina , Le Bris Cédric , Brauge Thomas , Midelet Graziella 

TITLE=Occurrence of Indicator Genes of Antimicrobial Resistance Contamination in the English Channel and North Sea Sectors and Interactions With Environmental Variables

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.883081

DOI=10.3389/fmicb.2022.883081

ISSN=1664-302X

ABSTRACT=<p>The marine environment is a potential natural reservoir of antimicrobial resistance genes (ARGs), subject to anthropogenic effluents (wastewater, industrial, and domestic), and known as a final receiving system. The aim of this study was to investigate the abundance and geographical distribution of the three <italic>bla<sub>TEM</sub></italic>, <italic>sul1</italic>, and <italic>intI1</italic> genes, proposed as indicators of contamination to assess the state of antimicrobial resistance in environmental settings, added to the <italic>tetA</italic> gene and the microbial population (<italic>tuf</italic> gene) in the English Channel and North Sea areas. Bacterial DNA was extracted from 36 seawater samples. The abundance of these genes was determined by quantitative PCR (qPCR) and was analyzed in association with environmental variables and geographical locations to determine potential correlations. The <italic>bla<sub>TEM</sub></italic> and <italic>tetA</italic> genes were quantified in 0% and 2.8% of samples, respectively. The <italic>sul1</italic> and <italic>intI1</italic> genes were detected in 42% and 31% of samples, respectively, with an apparent co-occurrence in 19% of the samples confirmed by a correlation analysis. The absolute abundance of these genes was correlated with the microbial population, with results similar to the relative abundance. We showed that the <italic>sul1</italic> and <italic>intI1</italic> genes were positively correlated with dissolved oxygen and turbidity, while the microbial population was correlated with pH, temperature and salinity in addition to dissolved oxygen and turbidity. The three <italic>tetA</italic>, <italic>sul1</italic>, and <italic>intI1</italic> genes were quantified in the same sample with high abundances, and this sample was collected in the West Netherlands coast (WN) area. For the first time, we have shown the impact of anthropogenic inputs (rivers, man-made offshore structures, and maritime activities) and environmental variables on the occurrence of three indicators of environmental contamination by antimicrobial resistance in the North Sea and English Channel seawaters.</p>