Frequency of colistin resistance in Pseudomonas aeruginosa: first report from Peru.

This study aimed to determine the frequency of colistin resistance in Pseudomonas aeruginosa isolates obtained from three healthcare facilities in Lima and cryopreserved at the Laboratorio de Resistencia Antimicrobianos e Inmunopatología of the Universidad Peruana Cayetano Heredia (UPCH). The colistin broth disk elution method was used for the phenotypic identification of colistin resistance. We detected the expression of the mcr-1 gene by using the phenotypic diffusion method with combined colistin and ethylenediaminetetraacetic acid (EDTA) disks; and polymerase chain reaction (PCR) was used for molecular identification of the gene.