Journal article
Rapid detection and differentiation of mobile colistin resistance (mcr-1 to mcr-10) genes by real-time PCR and melt-curve analysis
- Abstract:
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Background The emergence of multi-drug-resistant (MDR) micro-organisms prompted new interest in older antibiotics, such as colistin, that had been abandoned previously due to limited efficacy or high toxicity. Over the years, several chromosomal-encoded colistin resistance mechanisms have been described; more recently, 10 plasmid-mediated mobile colistin resistance (mcr) genes have been identified. Spread of these genes among MDR Gram-negative bacteria is a matter of serious concern; therefore, reliable and timely mcr detection is paramount.
Aim To design and validate a multiplex real-time polymerase chain reaction (PCR) assay for detection and differentiation of mcr genes.
Methods All available mcr alleles were downloaded from the National Center for Biotechnology Information Reference Gene Catalogue, aligned with Clustal Omega and primers designed using Primer-BLAST. Real-time PCR monoplexes were optimized and validated using a panel of 120 characterized Gram-negative strains carrying a wide range of resistance genes, often in combination. Melt-curve analysis was used to confirm positive results.
Findings In-silico analysis enabled the design of a ‘screening’ assay for detection of mcr-1/2/6, mcr-3, mcr-4, mcr-5, mcr-7, mcr-8 and mcr-9/10, paired with an internal control assay to discount inhibition. A ‘supplementary’ assay was subsequently designed to differentiate mcr-1, mcr-2, mcr-6, mcr-9 and mcr-10. Expected results were obtained for all strains (100% sensitivity and specificity). Melt-curve analysis showed consistent melting temperature results. Inhibition was not observed.
Conclusions The assay is rapid and easy to perform, enabling unequivocal mcr detection and differentiation even when more than one variant is present. Adoption by clinical and veterinary microbiology laboratories would aid the surveillance of mcr genes amongst Gram-negative bacteria.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Accepted manuscript, 651.6KB, Terms of use)
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(Supplementary materials, 948.1KB, Terms of use)
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- Publisher copy:
- 10.1016/j.jhin.2021.01.010
Authors
- Publisher:
- Elsevier
- Journal:
- Journal of Hospital Infection More from this journal
- Volume:
- 110
- Pages:
- 148-155
- Publication date:
- 2021-01-21
- Acceptance date:
- 2021-01-13
- DOI:
- ISSN:
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0195-6701
- Pmid:
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33485969
Terms of use
- Copyright holder:
- Healthcare Infection Society
- Copyright date:
- 2021
- Rights statement:
- © 2021 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.
- Notes:
- This is the accepted manuscript version of the article. The final version is available online from Elsevier at https://doi.org/10.1016/j.jhin.2021.01.010
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