Detection of Fluoroquinolones Resistance in Enterobacteriaceae and Pseudomonas species Using Molecular Techniques

Abstract

Quinolone resistance is traditionally mediated by chromosomal mutations that alter the target enzymes (DNA gyrase and/or topoisomerase IV), until plasmid mediated quinolones resistance (PMQR) was described in a clinical isolate of Klebsiella pneumoniae in 1998. Although the chromosomal mutations in quinolone resistance determining regions (QRDR) play an important role in conferring a high level of quinolone resistance, while the PMQR genes lead to increased minimal inhibitory concentrations (MICs) of quinolones in many cases but are still below susceptible MIC breakpoints, some of researchers believed that the acquisition of the hidden PMQR genes will accelerate the development of mutations in gyrA QRDR region that result in facilitating the emergence of high level resistance in the presence of quinolones at therapeutic levels and a decrease in therapeutic efficacy. This study was conducted on 100 non duplicate isolates, 64 Enterobacteriaceae spp. (32 klebsiella and 32 E.coli) and 36 Pseudomonas, recovered from clinical specimens referred to Central Microbiology Laboratory, Ain shams university Hospital for routine culture and sensitivity, aiming to determine the occurrence of PMQR determinants by multiplex PCR and chromosomal mutations by PCR