Plasmid-mediated quinolone resistance in expanded spectrum beta lactamase producing enterobacteriaceae in Morocco

Abstract

Introduction: Although independently acquired, plasmid-mediated quinolone resistance appears to be linked with extended-spectrum or AmpC-type beta-lactamases. Since no data are available in African countries, the prevalence of qnr genes at the University Hospital Ibn Rochd, Casablanca, Morocco, was investigated. Methodology: Between October 2006 and March 2007, the following 39 randomly selected non-duplicate Enterobacteriaceae producing an extended-spectrum beta-lactamase (ESBL), representing 20% of ESBL strains with respect to species and ward origin, were collected: Escherichia coli (n = 16); Klebsiella spp (n = 14); Enterobacter cloacae (n = 8); Proteus mirabilis (n = 1). Antibiotic susceptibility testing was performed according to CLSI guidelines. ESBL detection was performed by the double disc diffusion test. A multiplex PCR was conducted to detect qnrA, qnrB and qnrS genes that were confirmed by sequencing of the PCR product. Results: The estimated overall prevalence of qnr reached 36% (n = 14; qnrA, 10.25%; qnrB, 23.07%; qnrS, 2.56%). Genes were identified in E. coli, Klebsiella and Enterobacter with a respective prevalence of 18.7%, 50% and 62.5%. The qnr genes were detected in nine wards and qnrA1, qnrB1-B2-B4 and qnrS1 variants were identified. Three genes were identified among nalidixic acid susceptible strains (n = 6); three of those were also susceptible to ciprofloxacin. Among nalidixic acid and ciprofloxacin resistant strains, all strains had qnrB. Conclusions: This study highlights the high prevalence of qnr genes among ESBL strains in the Ibn Rochd CHU, Casablanca. Moreover, qnr were present in quinolone-susceptible strains which could lead to in vivo selection of ciprofloxacin-resistant strains.

Detection of plasmid-mediated qnr genes among the quinolone-resistant Escherichia coli isolates in Iran

“…Plasmid-mediated quinolone resistance mechanisms play an important role in the development of quinolone and fluoroquinolone resistance [14,15]. Urinary tract infections caused by such resistant isolates can be difficult to treat [2,6].…”

“…The qnrB is another plasmid-mediated quinolone resistant gene that has been identified worldwide and shares 43% amino acid identity with qnrA [13]. The horizontal transfer of plasmids carrying quinolone resistance determinants and the accumulation of chromosomal mutations play an important role in increasing rates of resistance [14,15].…”

Molecular characterization of extended spectrum β-lactamase-producing Escherichia coli in a university hospital in Morocco, North Africa

“…As for most developing countries in Africa, ESBL-producing bacteria have been examined in only a few studies. Limited data from prior studies conducted in Morocco suggest that ESBLs are common in Moroccan hospitals [6,7], with blaCTX-M, blaSHV and blaTEM genes representing the main reported ESBL families [8,9]. ESBL-producing E. coli isolates from the Marrakech region have not been characterized previously.…”

Detection of plasmid-mediated quinolone resistance determinants and qnrS expression in Enterobacteriaceae clinical isolates

“…Resistance to quinolones has increased globally in recent years, particularly in members of theEnterobacteriaceae [1][2]. Two main resistance mechanisms to quinolones are recognized: mutations in the quinoloneresistance-determining regions (QRDRs) of the chromosomal gyrA and parC genes, and decreased accumulation inside the bacteria due to impermeability of the membrane and/or an overexpression of efflux pump systems [3,4].…”