Environmental occurrence and dissemination of colistin resistance in contaminated aquatic systems: a systematic review of eight observational studies

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.