High diversity of pathogenic Escherichia coli clones carrying mcr‐1 among gulls underlines the need for strategies at the environment–livestock–human interface

Abstract

The expansion of mcr‐carrying bacteria is a well‐recognized public health problem. Measures to contain mcr spread have mainly been focused on the food–animal production sector. Nevertheless, the spread of MCR producers at the environmental interface particularly driven by the increasing population of gulls in coastal cities has been less explored. Occurrence of mcr‐carrying Escherichia coli in gull's colonies faeces on a Portuguese beach was screened over 7 months. Cultural, molecular and genomic approaches were used to characterize their diversity, mcr plasmids and adaptive features. Multidrug‐resistant mcr‐1‐carrying E. coli were detected for 3 consecutive months. Over time, multiple strains were recovered, including zoonotic‐related pathogenic E. coli clones (e.g. B2‐ST131‐H22, A‐ST10 and B1‐ST162). Diverse mcr‐1 genetic environments were mainly associated with ST2/ST4‐HI2 (ST10, ST131, ST162, ST354 and ST4204) but also IncI2 (ST12990) plasmids or in the chromosome (ST656). Whole‐genome sequencing revealed enrichment of these strains on antibiotic resistance, virulence and metal tolerance genes. Our results underscore gulls as important spreaders of high‐priority bacteria and genes that may affect the environment, food–animals and/or humans, potentially undermining One‐Health strategies to reduce colistin resistance.

Emergence of NDM-producing Enterobacterales infections in companion animals from Argentina

“…E. coli ST162 is a global virulent lineage that has been recovered from humans, environmental samples as well as from food, wild animals, and companion animals, and has been found associated with bla CTX-M and/or mcr-1 genes [30,31]. However, a unique carbapenemase-producing E coli ST162 was reported and recovered from lymph nodes sample from a pygmy sperm whale (Kogia breviceps) [32].…”

Boosting succinylation-dependent LPS biosynthesis to overcome colistin resistance

“…two component systems and the recently discovered mcr-1 that can be transmitted rapidly via horizontal gene transfer 15 . Mutations in the two-component systems cause hyperactivation of the regulatory system that constitutively adds 4-amino-4-dexoy-L-arabinose (L-Ara4N) to phosphate groups on lipid A, thus decreasing the net negative charge of LPS, and preventing colistin binding 16 .…”