Epidemiology of colistin resistance mediated by mcr-1 in carbapenemase-producing Enterobacterales in Ecuador in three periods from 2016 to 2022

Abstract

Carbapenemase-producing Enterobacterales (CPE) have increased in the last decade. In low-income countries, colistin is considered a last resort antimicrobial to treat CPE infections, whose most worrisome mechanism of resistance is MCR-1 production. This study aims to understand the epidemiology of colistin resistance in CPE in the region, through the surveillance of the mcr-1 gene in CPE isolates in Ecuador. A total of 361 CPE isolates were collected across three periods, from 2016 to 2022. Colistin resistance was assessed using the broth microdilution method and the most frequent carbapenemase-encoding genes and the mcr-1 gene were studied. Colistin resistance rate increased from 3.76% to 23.74% during the study period. The mcr-1 gene was not identified in any of the isolates studied and Klebsiella pneumoniae blaKPC was the most prevalent microorganism (n = 322; 89.20%). In conclusion, colistin resistance increased in CPE in Ecuador and was not mediated by the mcr-1 gene. Our results highlight the need to closely monitor national politics on antimicrobial resistance under the One Health Approach.

Este estudio tuvo como objetivo comprender la epidemiología de la resistencia a la colistina en Enterobacterales productores de carbapenemasas (EPC) en la región, a través de la vigilancia del gen mcr-1. Para ello se estudiaron 361 aislados de EPC de origen clínico obtenidos en Ecuador en tres momentos diferentes de los años 2016, 2020 y 2022. Se estudió la resistencia a colistina por microdilución en caldo y se identificaron los genes de las carbapenemasas más frecuentes y el gen mcr-1. Se observó un incremento en la resistencia a colistina del 3,76% al 23,74% durante el período estudiado. No se identificó el gen mcr-1 en ninguno de los aislados analizados; Klebsiella pneumoniae blaKPC fue el microorganismo más prevalente (89,20%). Nuestros hallazgos demuestran el incremento de la resistencia a colistina en EPC aislados en Ecuador no mediado por el gen mcr-1, lo que resalta la necesidad de ajustar las políticas nacionales para combatir la resistencia antimicrobiana.