Frontiers in antibiotics
Environmental occurrence and dissemination of colistin resistance in contaminated aquatic systems: a systematic review of eight observational studies
By Sinha A, Murmu J, Singh S and 6 others.
Abstract
Introduction
Colistin is a last-resort antibiotic used against multidrug-resistant Gram-negative bacterial infections. The emergence of plasmid-mediated colistin resistance, particularly mcr genes, has raised concerns about the environmental persistence and dissemination of resistance determinants. Aquatic environments may serve as reservoirs and dissemination pathways for colistin resistance; however, the available evidence remains fragmented. This systematic review aimed to synthesize evidence on the occurrence, resistance mechanisms, and environmental and potential public health implications of colistin resistance in contaminated aquatic systems.
Methods
A systematic literature search was conducted in five electronic databases up to December 2024 in accordance with PRISMA guidelines. Studies investigating colistin resistance in wastewater, surface water, aquaculture systems, and related aquatic environmental matrices were eligible for inclusion. Following screening and eligibility assessment, eight observational studies were included. Owing to substantial methodological and outcome heterogeneity, a narrative synthesis was performed. Isolate-level phenotypic resistance, sample- or site-level molecular positivity, and metagenomic relative gene abundance were analyzed as separate, non-comparable outcome strata.