Infection and Drug Resistance (Aug 2021)
Detection of Plasmid-Mediated Mobile Colistin Resistance Gene (mcr-1) in Enterobacterales Isolates from a University Hospital
Abstract
Mera Mohammed Galal Anan,1 Eman Ahmed El-Seidi,1 Marwa Salah Mostafa,1 Laila Ahmed Rashed,2 Doaa Mahdy El-Wakil1 1Department of Medical Microbiology and Immunology, Faculty of Medicine, Cairo University, Cairo, Egypt; 2Department of Biochemistry and Molecular Biology, Faculty of Medicine, Cairo University, Cairo, EgyptCorrespondence: Mera Mohammed Galal AnanDepartment of Medical Microbiology and Immunology, Faculty of Medicine, Cairo University, Kasr Al-Ainy St., Cairo, 11562, EgyptTel +20 1288866285Email [email protected]: Colistin represents one of the last treatment options for infections caused by multi-drug resistant (MDR) Enterobacterales. The emergence of a plasmid-mediated mobile colistin resistance-1 (mcr-1) gene has raised serious concerns about its potential dissemination among bacteria.Methods: In this study, we evaluated the chromogenic medium, CHROMID® Colistin Resistance (COLR) agar, for the rapid detection of colistin-resistant Enterobacterales using broth microdilution (BMD) as a reference method. We also attempted to detect mcr-1, − 2, − 3, − 4, and − 5 genes, as well as the insertion sequence ISApl1 via polymerase chain reaction (PCR), followed by sequencing of mcr gene(s).Results: Among the 100 studied Enterobacterales isolates, 53% of them were colistin-resistant, with higher rate among Klebsiella pneumoniae (75%) as compared to Escherichia coli (44.4%). The COLR agar showed 83.2% sensitivity and 97.9% specificity for the detection of colistin resistance. Among colistin-resistant isolates, mcr-1 gene was only detected in four (7.5%) E. coli isolates. The ISApl1 was not found among mcr-1 positive isolates. Sequencing of mcr-1 gene revealed nucleotide sequence homogeneity with the wild-type mcr-1 gene in BLAST.Conclusion: The COLR agar is a promising phenotypic method for the detection of colistin-resistant Enterobacterales. Multiplex PCR followed by sequencing can be used for mcr genes’ detection and characterization.Keywords: colistin resistance, Enterobacterales, mcr genes, CHROMID® COLR agar, multiplex PCR, sequencing
