Detection of mobile colistin-resistance gene variants (<i>mcr-1</i>and<i>mcr-2</i>) in urinary tract pathogens in Bangladesh: the last resort of infectious disease management colistin efficacy is under threat

Abstract

<b>Background</b>: Currently, colistin-resistant pathogens emerged has become a global health concern. This study assessed the distribution of <i>mcr-1</i> to <i>mcr-5</i> variants with the phenotypic colistin-resistance in bacterial isolates from urinary tract infection (UTI) patients in Bangladesh.<b>Methods</b>: A cross-sectional study was conducted between April 2017 and March 2018 to enroll uncomplicated UTI patients, and 142 urine samples were analyzed. Uropathogens were identified using the API-20E biochemical panel and 16s rRNA gene sequencing. Polymerase chain reactions detected the <i>mcr</i> gene variants in the UTI isolates. The phenotypic colistin-susceptibility was determined by the Kirby-Bauer disc-diffusion method and the minimal inhibitory concentration (MIC) measurement.<b>Results</b>: The combined carriage of <i>mcr-1</i> and <i>mcr-2</i> genes in 11.4% (14/123) of urinary tract pathogens. The <i>mcr</i>-positive pathogens include five <i>Escherichia coli</i>, three <i>Klebsiella pneumoniae</i>, three <i>Pseudomonas putida</i>, two <i>Enterobacter cloacae</i>, and one <i>Enterobacter hormaechei</i>. The <i>mcr-</i>positive variant showed significantly higher phenotypic colistin resistance with MIC between >16 µg/mL and >128 µg/mL (<i>p</i>< 0.001). Over 85% of colistin-resistant isolates showed MDR phenomena.<b>Conclusions</b>: The emergence of the clinical MDR pathogens with resistance to a highly selective drug may lead to a lack of treatment options for the infectious diseases and spread of infection to the unaffected cohorts.