engleski

Abundance of macrolide resistance genes and bacterial community composition from urban river sediments contaminated with macrolide antibiotics

Urban rivers are impacted ecosystems which may play an important role as reservoirs for antibiotic-resistant bacteria and the genes encoding for that resistance. Under anthropogenic input of antibiotics, there is an increased risk for recruitment of some of these resistance genes into pathogens by horizontal gene transfer. The main objective of this study was to explore the abundance of macrolide resistance genes and community composition in sediments along the Sava river (Croatia) receiving treated effluents from azithromycin production. Quantitative PCR analysis showed significant increase in the relative abundance of five targeted macrolide resistance genes in downstream sediments in comparison to reference upstream sediment. Abundance of analysed resistance genes correlated directly with antibiotic and metal concentrations, indicating their importance in selection of resistance genes. Bacterial community composition of the sediment from the discharge site was significantly different from community composition of upstream sample, while no significant difference was found between community composition of the downstream and upstream sediments. Our results confirm that chronic discharges of macrolide polluted effluents from azithromycin production contribute to the spread of macrolide resistance genes in the receiving river and may also impact on the bacterial communities in river sediments.

macrolide resistance genes ; river sediments

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