Plasmid-mediated quinolone resistance among extended spectrum beta lactase producing Enterobacteriaceae from bloodstream infections

Gulyás

et al. 2018

AMicr

Self Cite

Plasmid-mediated quinolone resistance (PMQR) determinants including, qnrA, qnrB, qnrC, qnrD, qnrS, aac(6')-Ib-cr, oqxAB, and qepA, were investigated in 214 Enterobacteriaceae strains from urine clinical samples. Antimicrobial susceptibility testing for ciprofloxacin, ceftriaxone, and imipenem was performed by broth microdilution method. All strains were screened for PMQR genes by PCR. Virulence determinants, namely afa, pap, pil, sfa/foc, and kpsMT of eight Escherichia coli strains proven positive for at least one qnr gene, were investigated by PCR. All of the eight investigated strains carried the pil gene, showing that P fimbria is a common virulence determinant among qnr positive E. coli. Out of 214 tested strains, 38 yielded any PMQR determinant, altogether 45 genes were detected namely, 6 qnrA, 1 qnrB, 2 qnrD and 8 qnrS, 9 aac(6')-Ib-cr, and 19 oqxAB; however, neither qepA nor qnrC were detected. Notably, 18 Klebsiella spp., harbored oqxAB, nine E. coli were positive for qnrS and two Morganella morganii yielded qnrD resistance determinant. In this study, we demonstrated 17.7% prevalence of PMQR-positive Enterobacteriaceae and first reported qnrD-resistance determinant in Hungary. Altogether, 25 PMQR-positive strains were susceptible or low-level resistant to ciprofloxacin with minimum inhibitory concentration (MIC) between 0.06 and 1 mg/L, suggesting that prevalence of PMQR determinants is underestimated and screening among clinical isolates exhibiting reduced susceptibility is necessary. Fluoroquinolone resistance breakpoints of Enterobacteriaceae were revised in 2017 by European Committee of Antimicrobial Susceptibility Testing indicating ciprofloxacin susceptibility only until 0.25 mg/L MIC value.

Section: Discussionmentioning

confidence: 62%

“…According to international data, the prevalence of PMQR genes, qnrA, qnrB, qnrS, aac(6′)-Ib-cr, and qepA is associated with ESBLs, but actual prevalence of qnrC is unknown; however, some data are released about qnrD [6,17,30].…”

mentioning

confidence: 99%

Plasmid-mediated quinolone resistance determinants in Enterobacteriaceae from urine clinical samples

Gulyás

et al. 2018

AMicr

Self Cite

“…Earlier studies demonstrated OqxAB efflux pump in extended-spectrum beta-lactamase-producing and fluoroquinolone-resistant K. pneumoniae high-risk clones [ 19 – 21 ]. In Hungary, K. pneumoniae with oqxAB resistance determinant was reported in bloodstream infections [ 22 ]. In all these reported studies, tested strains were resistant to fluoroquinolones.…”

Section: Discussionmentioning

confidence: 99%

Contribution of OqxAB Efflux Pump in Selection of Fluoroquinolone-Resistant Klebsiella pneumoniae

Kocsis

Canadian Journal of Infectious Diseases and Medical Microbiolog

et al. 2018

The role of OqxAB efflux pump in Klebsiella pneumoniae was investigated in correlation with ciprofloxacin exposure. K. pneumoniae SE23 and K. pneumoniae SE191 were isolated from urinary tract infections and were analyzed in this study. Each carried oqxAB resistance determinant and exhibited ciprofloxacin MIC of 0.06 and 0.5 mg/L, respectively. Tested strains were initially exposed to their ciprofloxacin MIC values for 24 hours. Later on, the ciprofloxacin exposition has been increased to a daily 1, 2, 4, and to a final 8 mg/L. Total cellular RNA was extracted at 30, 60, 90, and 120 minutes of initial exposure and after every 24 hours. Quantitative reverse-transcriptase PCR was performed from each RNA sample. Mutation in gyrA and parC genes was analyzed in each strain and multilocus sequence typing (MLST) was performed. Ciprofloxacin exposure selected resistant strain from K. pneumoniae SE191; by contrast, K. pneumoniae SE23 was not adjustable to the increasing ciprofloxacin concentrations. During initial exposure, both oqxA and oqxB expression remained low (2−ΔCt = 1-2.03). However, increasing ciprofloxacin promoted oqxB expression as it reached fold increase of 15.8–22.8, while oqxA expression was maintained (2−ΔCt = 2-2.15). An amino acid substitution Ser83Tyr in gyrA was detected in K. pneumoniae SE191, but no additional mutations occurred as consequence to ciprofloxacin exposure. MLST identified K. pneumoniae SE191 as ST274, while K. pneumoniae SE23 belonged to the novel ST2567. Ciprofloxacin concentration-dependent upregulation of oqxAB efflux pump in K. pneumoniae is clonally related and contributes to selection for higher level of fluoroquinolone resistance.

“…Recently, plasmid-mediated quinolone resistance determinants have been also reported among E. coli isolates, furthermore, plasmid-mediated fosfomycin-modifying enzymes, fosA3 and fosC2, were identified in E. coli clinical isolates. Acquisition of these fosfomycin resistance determinants, which inactivate fosfomycin by exerting glutathione-S-transferase activity, has also been seem to confer resistance [19,25]. Although phenotypic test reported eight isolates of E. coli as fosfomycin-resistant strains, molecular test showed that none of them had the fosA3 or fosC2 genes.…”

Section: Discussionmentioning

confidence: 99%

Emergence of fosfomycin resistance among isolates of Escherichia coli harboring extended-spectrum and AmpC β-lactamases

Bahramian

Eslami

Hashemi

et al. 2017

AMicr

Urinary tract infection (UTI) is a common type of infectious disease globally. The aim of this study was to detect the frequency of fosA3 and fosC2 genes in extended-spectrum β-lactamases (ESBL) and bla, bla, and bla genes in AmpC β-lactamases-producing isolates of Escherichia coli. In total, 120 isolates of E. coli were collected from three teaching hospitals between March 2014 and February 2015. Antibiotic susceptibility tests were carried out by disk diffusion method. The presence of bla, bla, bla, fosA3, and fosC2 genes was detected by polymerase chain reaction (PCR) and sequencing. Of the 120 strains, 92 (76.6%) were identified as ESBL producers, 30 (25%) were determined as AmpC β-lactamase producers, and 24 (20%) had both ESBL and AmpC β-lactamase enzymes. Imipenem, fosfomycin, and nitrofurantoin had the best effect against isolates of E. coli. PCR assay demonstrated that the frequency of bla, bla, and bla genes among AmpC β-lactamases-producing strains were 39%, 1%, and 17.5%, respectively. This study reports the first detection of fosfomycin resistance in Iran. This study indicated the increasing prevalence of UTI isolates of E. coli-harboring ESBL and AmpC β-lactamases genes in Iran. Therefore, due to the high rate of bla and bla genes and emergence of fosfomycin-resistant E. coli isolates, we recommend continuous monitoring of antibiotic resistance as well as attention to guidelines of infection controls.