In treacherous waters: detection of colistin resistant bacteria in water and plastic litter from a recreational estuary.
Gabrielle da Silva Oliveira AlvesAnna Luiza Bauer CanellasMarcos N GalloSusana Beatriz VinzonMarinella Silva LaportPublished in: Letters in applied microbiology (2024)
Colistin resistance poses a major therapeutic challenge and resistant strains have now been reported worldwide. However, the occurrence of such bacteria in aquatic environments is considerably less understood. This study aimed to isolate and characterize colistin resistant strains from water and plastic litter collected in an urban recreational estuary. Altogether, 64 strains with acquired colistin resistance were identified, mainly Acinetobacter spp. and Enterobacter spp. From these, 40.6% were positive for at least one mcr variant (1-9), 26.5% harbored extended-spectrum beta-lactamases, 23.4%, sulfonamide resistance genes, and 9.3%, quinolone resistance genes. The merA, encoding mercury resistance, was detected in 10.5% of these strains, most of which were also strong biofilm producers. The minimum inhibitory concentration towards colistin was determined for the mcr positive strains and ranged from 2 to ≥ 512 µg.ml-1. Our findings suggest that Gram-negative bacteria highly resistant to a last-resort antimicrobial can be found in recreational waters and plastic litter, thereby evidencing the urgency of the One Health approach to mitigate the antimicrobial resistance crisis.
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