Plasmidic resistance to colistin mediated by mcr-1 gene in Escherichia coli clinical isolates in Argentina
A retrospective study, 2012–2018
Bibliographic Data
Objective. To describe the resistance profile and the genetic characteristics of Escherichia coli isolates that harbor the mobilizable colistin resistance gene mcr-1 in Argentina. Methods. This was a retrospective study of 192 E. coli isolates positive for mcr-1 obtained from 69 hospitals of Buenos Aires City and 14 Argentinean provinces in 2012 – 2018. The antimicrobial susceptibility was performed by agar diffusion, broth macrodilution, and/or agar dilution. Standard polymerase chain reaction (PCR) was performed to detect resistance genes and incompatibility groups; specific PCR was applied to discriminate between blaCTX-M allelic groups and mcr-1.5 variant. The genetic relatedness among isolates was evaluated by XbaI-pulsed field gel electrophoresis and multilocus sequence typing in a subset of isolates. Results. All E. coli isolates showed minimal inhibitory concentrations to colistin = 4μg/mL; nearly 50% were resistant to third-generation cephalosporins, with CTX-M-2 being the main extended-spectrum β-lactamase detected. Five E. coli were carbapenemase-producers (3 NDM, 2 KPC). The mcr-1.5 variant was detected in 13.5% of the isolates. No genetic relationship was observed among the mcr-1-positive E. coli clinical isolates, but a high proportion (164/192; 85.4%) of IncI2 plasmids was detected. Conclusions. The presence of IncI2 plasmids among highly diverse E. coli clones suggests that the mcr-1 gene’s wide distribution in Argentina may be driven by the horizontal transmission of IncI2 plasmids
Agar · Agar dilution · Antimicrobial · Bacteria · Biology · Colistin · Enterobacteriaceae · Escherichia coli · Gene · Genotype · MCR-1 · Minimum inhibitory concentration · Multilocus sequence typing · Plasmid · Polymerase chain reaction · Pulsed-field gel electrophoresis · Typing · Antibiotic Resistance in Bacteria · Antibiotics Pharmacokinetics and Efficacy · Pharmaceutical and Antibiotic Environmental Impacts · Genetics · Microbiology
| Citations per year | 0.2 |
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| Citation span | 2021 - 2021 (1) |
| Highly cited | No |