1. Analysis of molecular mechanisms of delafloxacin resistance in Escherichia coli.
- Author
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Kubicskó A, Kamotsay K, Szabó D, and Kocsis B
- Subjects
- Mutation, Whole Genome Sequencing, Humans, DNA Gyrase genetics, DNA Topoisomerase IV genetics, Escherichia coli Infections microbiology, Escherichia coli Infections drug therapy, beta-Lactamases genetics, Escherichia coli genetics, Escherichia coli drug effects, Fluoroquinolones pharmacology, Microbial Sensitivity Tests, Anti-Bacterial Agents pharmacology, Drug Resistance, Bacterial genetics
- Abstract
In this study delafloxacin resistance mechanisms in Escherichia coli strains were analyzed. Delafloxacin is a new fluoroquinolone, that is approved for clinical application however, resistance against this agent is scarcely reported. In our study 37 E. coli strains were included and antimicrobial susceptibility testing was performed for ciprofloxacin, delafloxacin, levofloxacin, moxifloxacin, ceftazidime, cefotaxime, imipenem. Six delafloxacin resistant E. coli strains were selected for whole-genome sequencing and all of them exhibited resistance to other fluoroquinonlones and showed an extended-spectrum beta-lactamase phenotype. The six delafloxacin resistant E. coli strains belonged to different sequence types (STs) namely, ST131 (2 strains), ST57 (2 strains), ST162 and ST15840. Each delafloxacin resistant strain possessed multiple mutations in quinolone resistance-determining regions (QRDRs). Notably, three mutations in gyrA Ser83Leu, Asp87Asn and parC Ser80Ile were in strains of ST162, ST57 and ST15840. However, the two strains of ST131 carried five combined mutations namely, gyrA Ser83Leu, Asp87Asn, parC Ser80Ile, Glu84Val, parE Ile549Leu. Association of delafloxacin resistance and production of CTX-M-15 in ST131, CMY-2 in ST162 and ST15840 was detected. In this study a new ST, ST15840 of clonal complex 69 was identified. Our results demonstrate, that at least three mutations in QRDRs are required for delafloxacin resistance in E. coli., (© 2024. The Author(s).)
- Published
- 2024
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