Plasmid-mediated quinolone resistance determinants among Gram-negative bacteraemia isolates: A hidden threat.

Plasmid-mediated quinolone resistance determinants among Gram-negative bacteraemia isolates: A hidden threat. J Med Microbiol. 2016 Nov 28;: Authors: Margaritis A, Galani I, Chatzikonstantinou M, Petrikkos G, Souli M Abstract The aim of the study was to investigate the prevalence of PMQR genes in an unselected collection of bloodstream isolates recovered over an 18-month period in a laboratory affiliated to a University Hospital in Athens, Greece and to assess their impact on the in vitro activity of ciprofloxacin and levofloxacin. Eight PMQR genes were screened by PCR and sequencing. All PMQR-positive isolates were submitted to isoelectric focusing for β-lactamase detection, conjugation or transformation, time-kill assays, MPC and inoculum effect evaluation. PCR and sequencing of gyrA and parC were performed for detection of chromosomal mutations. Among 96 Gram-negative isolates, 7(7.3%) carried one or more PMQR genes. qnrS1 was the most prevalent(5.2%), followed by aac(6')-Ib-cr(4.2%) and their combination(2%). Cloning was successful for three isolates. The presence of a single PMQR determinant without any target modification was not associated with quinolone resistance with one exception; S.maltophilia carrying qnrS1, which was resistant to norfloxacin and ciprofloxacin but in this isolate, additional mechanisms of quinolone resistance cannot be excluded. All PMQR-positive isolates showed a significant inoculum effect. The MPCs o...
Source: Journal of Medical Microbiology - Category: Microbiology Authors: Tags: J Med Microbiol Source Type: research