Quinolone and Colistin Resistance Genes in Extended-Spectrum Beta-Lactamase (ESBL)-Producing <i>Escherichia coli</i> of Diverse Phylogenetic Groups Isolated from Seafood in Mumbai, India
Contamination of coastal-marine environment with multidrug-resistant <i>Escherichia coli</i> has resulted in such bacteria increasingly being detected in the seafood chain. This study aimed to determine the quinolone and colistin resistance genes in extended spectrum-β-lactamase (ESBL)-p...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Applied Microbiology |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2673-8007/5/1/3 |
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| Summary: | Contamination of coastal-marine environment with multidrug-resistant <i>Escherichia coli</i> has resulted in such bacteria increasingly being detected in the seafood chain. This study aimed to determine the quinolone and colistin resistance genes in extended spectrum-β-lactamase (ESBL)-producing <i>E. coli</i> from seafood. ESBL-producing <i>E. coli</i> isolates (n = 269) were tested for quinolones and colistin resistance phenotypes by disk diffusion and broth microdilution methods, respectively. The isolates were further PCR screened for the plasmid-mediated quinolone resistance (PMQR) genes <i>qnrA</i>, qnrB, and <i>qnrS</i>, genomic mutations in <i>gyrA</i> and <i>parC</i> genes, and the colistin resistance genes <i>mcr-1</i> and <i>mcr-2</i>. Phylogroup was determined by PCR using the Clermont <i>E. coli</i> phylotyping method. Of 269 isolates tested, 73.60% of <i>E. coli</i> isolates were resistant to moxifloxacin and 8.55% to ofloxacin, the least of all the quinolones tested. Further, 150 (55.76%) <i>E. coli</i> isolates carried at least one of the three PMQR genes tested, where <i>qnrS</i> was the most prevalent gene (53.90%). The colistin resistance gene (<i>mcr-2</i>) was detected in 38 (14.12%) isolates. Twenty-one of these isolates (55.26%) had a colistin minimum inhibitory concentration (MIC) of 16 µg/mL. Based on the Clermont <i>E. coli</i> phylotyping of the isolates harboring at least one of the <i>qnr</i> genes, 66 (44%) belonged to the phylogroup B1, followed by 23 (15.33%) to phylogroup A. Among 38 <i>E. coli</i> isolates carrying colistin resistance gene <i>mcr-2</i>, 27 (71.05%) isolates belonged to phylogroup B1, followed by 4 (10.52%) isolates to phylogroup A. The results suggest that <i>E. coli</i> phylogroups B1 and A harboring plasmid-mediated quinolone and colistin resistance genes are predominant in the seafood supply chain. |
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| ISSN: | 2673-8007 |