Molecular characterization of fluoroquinolone resistant Escherichia coli from Ghana

Background: The indiscriminate use of antibiotics in humans and animals has led to an increase in drug resistant bacteria. This has become a global health threat and a limitation to first- and second-line antibiotic treatment options with consequences including treatment failure and higher medical cost. Using Escherichia coli (E. coli) as an indicator of resistant bacteria, the study sought to determine the distribution of antibiotic resistant isolates from clinical samples and characterize quinolone-resistant genes. Methods and materials: Methods: An experimental quantitative approach was adopted to obtain clinical samples followed by strain identification and antimicrobial susceptibility testing. E-tests were used to determine the Minimum Inhibitory Concentration (MIC) for ciprofloxacin resistant isolates after which chromosomal DNA and plasmids were extracted and probed for the genes (gyr A, parC, aac(6′)1bcr gyr B, Qnr A, Qnr B, Qnr C, Qnr S, qep A and oqx B) known to confer ciprofloxacin–resistance. The amplicons were sequenced and analyzed for mutational hot spots. Results: In total, 47/83 (56.6%) E. coli isolates were resistant to ciprofloxacin and 29/47 (61.7%) showed MIC > 32 μg/mL. Majority 21/29 (72.4%) of the ciprofloxacin resistant E. coli were positive for Gyr A and mutations were found within codon 83 and 87. In parC, the mutations were at codons 71 and 80. Conclusion: The study revealed a high prevalence of fluoroquinolone resistance and found chromosomal and plasmid mediated genes to be widespread and linked to ciprofloxacin-resistance in Ghana. The putative mutations in Quinolone Resistance Determining Regions (QRDR) and the new mutations identified in parC requires further investigations into its association with ciprofloxacin-resistant E. coli. However the preliminary data justifies the need for intensified surveillance in Ghana.

Abstract licence: CC BY-NC-ND

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