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

Abstract

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 blaTEM, sul1, and intI1 genes, proposed as indicators of contamination to assess the state of antimicrobial resistance in environmental settings, added to the tetA gene and the microbial population (tuf 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 blaTEM and tetA genes were quantified in 0% and 2.8% of samples, respectively. The sul1 and intI1 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 sul1 and intI1 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 tetA, sul1, and intI1 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.

Microbial source tracking and land use associations for antibiotic resistance genes in private wells influenced by human and livestock fecal sources

“…Importantly, human and bovine fecal contamination of these wells was associated with estimates of significant health risk (Burch et al, 2021). Therefore, while intI1 may indicate abundant fecal contamination or aggregated fecal influence (Beattie et al, 2018;Bourdonnais et al, 2022;Kampouris et al, 2021;Keely et al, 2022;Lee et al, 2021), our results suggest that it may not accurately predict contamination in all settings, like rural areas with dispersed septic systems and variable manure inputs.…”

Monitoring indicator genes to assess antimicrobial resistance contamination in phytoplankton and zooplankton communities from the English Channel and the North Sea

“…Quantification cycle (Cq) values were calculated using the second derivate method. The reagents, amplification conditions and controls used are indicated in our previous publication (Bourdonnais et al, 2022a ).…”

“…Over the last few years, research on the occurrence of ARGs and ARB in the different environmental compartments has expanded, leading to the publication of comprehensive reviews on AMR factors and pathways in the environment (Singer et al, 2016 ; Irfan et al, 2022 ; Larsson and Flach, 2022 ). These emerging environmental contaminants have been isolated from the soils and sediments (up to 10 9 gene copies/g), sewage (up to 10 −4 gene copies/16S rDNA gene copies), rivers (around 10 5 gene copies/ml), lakes (up to 10 −4 gene copies/16S rDNA gene copies), seawaters (up to 2.9 log gene copies/ng of DNA) and even in remote areas such as the Arctic (around 10 −4 gene copies/16S rDNA gene copies) and the clouds (up to 10 4 gene copies/m 3 of air; Yang et al, 2017 ; McKinney et al, 2018 ; Tan et al, 2018 ; Nnadozie and Odume, 2019 ; Alessia et al, 2020 ; Bourdonnais et al, 2022a ; Rossi et al, 2023 ). Even if the terrestrial and anthropogenic sources are often studied, the role of seas and oceans in the spread of ARGs is still understudied.…”

“…These trophic levels are based on the study conducted by Giraldo et al ( 2017 ) in the English Channel and have been simplified as follows. Level 0 of the food chain corresponds to surface waters, for which results on their “contamination” by the indicator genes have been previously published (Bourdonnais et al, 2022a ). The phytoplankton and zooplankton studied in this work belong to levels 1 and 2, respectively.…”

Sources and contamination routes of seafood with human pathogenic Vibrio spp.: A Farm‐to‐Fork approach

“…benefit from different reservoirs in the natural aquatic environment, anthropogenic activities, and related pollution from hospital, urban and industrial effluents may impact aquatic ecosystems, altering the ecology of microbial communities, and subsequently affect the prevalence and abundance of pathogens in raw seafood (Nogales et al., 2011). A close relationship with anthropogenic areas, reservoirs of antimicrobial resistance (AMR) genes, will naturally lead to increased prevalence of AMR with related therapeutic failure threatening animal and human safety (Bourdonnais et al., 2022). Consequences and risk factors of the propagation of AMR within human pathogenic Vibrio spp.…”