Comparative Evaluation of Phenotypic Assays for Detecting mcr-Mediated Colistin Resistance in Acinetobacter baumannii: Phenotypic Assays for mcr-Mediated Colistin Resistance in Acinetobacter baumannii

Mubashir Raza; Saadullah Jan Khan; Roomana Ali; Muhammad Faisal Masood; Laila Jafri; Rehana Rani; Sara Sadiq; Nausheen Akhtar; Bushra Jamil

doi:10.54393/fbt.v4i04.190

Authors

Mubashir Raza Department of Life Sciences, Abasyn University, Islamabad, Pakistan
Saadullah Jan Khan Research Institute for Health Sciences, Chiang Mai University, Chiang Mai, Thailand https://orcid.org/0009-0002-5648-9354
Roomana Ali Department of Life Sciences, Abasyn University, Islamabad, Pakistan
Muhammad Faisal Masood Department of Life Sciences, Abasyn University, Islamabad, Pakistan
Laila Jafri Department of Biological Sciences, Faculty of Life Sciences, Health Services Academy, Islamabad, Pakistan https://orcid.org/0000-0003-4033-6337
Rehana Rani Department of Life Sciences, Abasyn University, Islamabad, Pakistan https://orcid.org/0009-0001-2936-2668
Sara Sadiq BJ Micro Lab, Rawalpindi, Pakistan https://orcid.org/0009-0006-8015-5628
Nausheen Akhtar Department of Biological Sciences, National University of Medical Sciences, Rawalpindi, Pakistan https://orcid.org/0000-0003-3413-9150
Bushra Jamil BJ Micro Lab, Rawalpindi, Pakistan https://orcid.org/0000-0001-7572-8942

DOI:

https://doi.org/10.54393/fbt.v4i04.190

Keywords:

Mobile Colistin Resistance Genes, Minimum Inhibitory Concentration, Antimicrobial Susceptibility Testing, Colistin Resistance

Abstract

Acinetobacter baumannii that is resistant to colistin has proven to be a significant problem in neonatal intensive care units (NICUs), where neonates are highly susceptible to multidrug-resistant pathogens. The introduction of plasmid-mediated mobile colistin resistance (mcr) genes has added to the global panic, but the prevalence of these genes in neonatal isolates is limited in South Asia. Objectives: To establish the frequency of mcr-1 to mcr-5 genes in colistin-resistant A. baumannii isolates of NICU patients and to compare the phenotypic assay of colistin susceptibility to establish a dependable and affordable diagnostic tool. Methods: Sources of thirteen A. baumannii isolates were blood samples, urine samples, and respiratory samples of NICU patients. Colistin resistance in carbapenem-resistant isolates was determined by disc diffusion, broth macro-dilution, disc elution, colistin agar, and minimum inhibitory concentration (MIC). Mcr gene screening was done genotypically using PCR and gene-specific primers. Results: Eight (61.5) isolates had the mcr-1 gene with no detection of mcr-2 to mcr-5. Isolates were all colistin resistant, with MICs ranging from 16 -32 μg/ml. Colistin agar method gave similar results to the broth assays, and it was found that it is a viable and low-cost alternative to parallel screening. Conclusions: This research is the first reported case of mcr-1-mediated colistin resistance in clinical isolates of A. baumannii in a neonatal unit in Pakistan. Enhanced antimicrobial stewardship and resistance monitoring of neonatal care are needed. In resource-limited settings, the colistin agar method is suggested to be used as a routine laboratory screening.

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