First Case of Qnr B6 and Qnr B7 Genes in Enterobacteriaceae Producing Extended-Spectrum Beta-Lactamases in Abidjan, Côte D'ivoire

Aims: The aim of this study was to characterize fluoroquinolone resistance genes in enterobacteriaceae that produce extended-spectrum β-lactamases, isolated in Abidjan.

Place and Duration of Study: Pasteur Institute of Côte d'Ivoire and research unit on emerging tropical infectious diseases of Aix-Marseille University from January 2017 at July 2017.

Methodology: The study included 90 enterobacteriaceae producing extended-spectrum β-lactamases isolated from biological products from various hospital services in Abidjan. These strains have been pre-identified and stored at the Center for Biological Resources (CeReB) of Pasteur Institute of Côte d'Ivoire. The identification of the strains was confirmed using the mass spectrometry MALDI-TOF (MS) and the antibiotic sensitivity test was performed using Müeller Hinton's agar diffusion method. The fluoroquinolone resistant genes were detected by conventional PCR and then, sequenced.

Results: The strains studied were Escherichia coli (44), Klebsiella pneumoniae (31) and Enterobacter cloacae (15). High resistance rates to ceftriaxone (96.7%), cefotaxime (95.6%), aztreonam (95.6%) and cefoxitin (72.2%) were observed in all strains producing broad spectrum β-lactamases. The resistance rate to fluororquinolones represented by ciprofloxacin was 86.7%. The fluoroquinolone resistance genes detected were qnr A (3.3%) and qnr B (42.2%). Sequencing identified the qnr A1 (3.3%), qnr B1 (31.1%), qnr B6 (2.2%) and qnr B7 (1.1%) genes.

Conclusion: This study made it possible to identify fluoroquinolone resistance genes in enterobacteriaceae producing β-lactamases which have an extended spectrum in Abidjan.