Detection of plasmid-mediated mcr-1 gene in multidrug-resistant Escherichia coli from clinical specimens at a tertiary hospital in Nepal
Abstract. Background:. The emergence of antibiotic resistance, particularly plasmid-mediated colistin resistance, poses a critical threat to global public health, given colistin’s role as a last-resort antibiotic for treating multidrug-resistant (MDR) bacterial infections. Despite its significance,...
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| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wolters Kluwer Health - Lippincott Williams Wilkins
2025-04-01
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| Series: | Infectious Diseases & Immunity |
| Online Access: | http://journals.lww.com/10.1097/ID9.0000000000000157 |
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| Summary: | Abstract.
Background:. The emergence of antibiotic resistance, particularly plasmid-mediated colistin resistance, poses a critical threat to global public health, given colistin’s role as a last-resort antibiotic for treating multidrug-resistant (MDR) bacterial infections. Despite its significance, data on colistin resistance and the prevalence of mobile colistin resistance (mcr) genes in Nepal are scarce. This study aims to investigate the occurrence of plasmid-mediated mobilized colistin resistance genes mcr-1 and mcr-2 in MDR Escherichia coli isolates from clinical specimens, highlighting the burden of resistance and its clinical implications in Nepalese context.
Methods:. A hospital-based cross-sectional study was conducted at Sukraraj Tropical Infectious Disease Hospital in Kathmandu from March to August 2022. A total of 1358 clinical specimens were processed using standard microbiological techniques. Antibiotic susceptibility testing followed the Kirby-Bauer disk diffusion method per the 2016 Clinical and Laboratory Standards Institute guidelines. The minimum inhibitory concentration (MIC) for colistin was determined via agar dilution method. Colistin-resistant strains were further investigated for the detection of mcr-1 and mcr-2 genes using endpoint polymerase chain reaction.
Results:. A total of 86 E. coli isolates were recovered with a prevalence rate of 6.3% (86/1358). Higher growth rates of E. coli were observed among females (9.0%, 56/620), individuals aged 46–60 years (8.5%, 23/271), and in pus samples (3 out of 7). Majorities of the isolates exhibited high resistance rates towards beta-lactam antibiotics and cotrimoxazole, with 81.4% (70/86) classified as MDR. The MIC of colistin was ≥ 4 μg/mL in 7 isolates. The prevalence of extended-spectrum beta-lactamase (ESBL)-, metallo-beta-lactamase (MBL)-, and klebsiella pneumoniae carbapenemases-producing isolates was 40.7% (35/86), 14.0% (12/86), and 1.2% (1/86), respectively. The mcr-1 gene was detected in 5 colistin-resistant isolates, while mcr-2 was not identified. Notably, all ESBL- and MBL-producing isolates were also MDR, with higher proportions of ESBL-producing (4 out of 5) and MBL-producing (1 out of 5) strains among those harboring the mcr-1 gene.
Conclusions:. This study highlights a concerning prevalence of mcr-1-mediated colistin resistance in E. coli isolates, compounded by co-resistance to other critical antibiotics such as beta-lactams and carbapenems. The findings underscore the urgent need for enhanced surveillance, antimicrobial stewardship, and research into colistin resistance mechanisms for preventing further escalation of the resistance burden. |
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| ISSN: | 2096-9511 2693-8839 |