Colistin-resistant Escherichia coli with mcr genes in the livestock of rural small-scale farms in Ecuador

Yoshimasa YamamotoEmail author View ORCID ID profile,
Manuel Calvopina,
Ricardo Izurieta,
Irina Villacres,
Ryuji Kawahara,
Masahiro Sasaki and
Mayumi Yamamoto

BMC Research Notes201912:121

https://doi.org/10.1186/s13104-019-4144-0

Received: 26 December 2018
Accepted: 21 February 2019
Published: 4 March 2019

Abstract

Objective

Emergence and dissemination of colistin-resistant (Co-R) bacteria harboring mobile colistin resistance genes pose a threat for treatment of infections caused by multi-drug resistant bacteria. Although the worldwide spread of Co-R bacteria is known, the precise state of Co-R bacterial dissemination in livestock of Andean countries remains unclear. Therefore, we investigated mcr-containing Co-R Escherichia coli dissemination in livestock on small-scale farms in two socioecologically different regions of Ecuador: the Amazonian rain-forest and the Pacific Coast.

Results

Sixty-six rectal swab samples from 34 pigs and 32 chickens, from five farms in the two regions, were assessed for the dissemination of Co-R E. coli using the selective medium CHROMagar™ COL-APSE. mcr-containing Co-R E. coli were detected in the specimens at a high rate (47%; 31/66), but the detection rates of the two regions were not statistically different. Both chickens and pigs showed similar detection rates. All Co-R E. coli isolates harbored mcr-1. The minimum inhibitory concentrations of colistin were ≥ 8 mg/L, and 67.7% (21/31) of the Co-R isolates were multi-drug resistant. Pulsed-field gel electrophoresis revealed the limited relation between isolates. Thus, we revealed the high rate of widespread dissemination of Co-R bacteria in livestock regardless of the socioecological conditions in Ecuador.