Presence of qnr gene in Escherichia coli and Klebsiella pneumoniae resistant to ciprofloxacin isolated from pediatric patients in China

Abstract

BackgroundQuinolone resistance in Enterobacteriaceae results mainly from mutations in type II DNA topoisomerase genes and/or changes in the expression of outer membrane and efflux pumps. Several recent studies have indicated that plasmid-mediated resistance mechanisms also play a significant role in fluoroquinolone resistance, and its prevalence is increasing worldwide. In China, the presence of the qnr gene in the clinical isolates of Enterobacteriaceae has been reported, but this transmissible quinolone resistance gene has not been detected in strains isolated singly from pediatric patients. Because quinolones associated with a variety of adverse side effects on children, they are not authorized for pediatric use. This study therefore aimed to investigate the presence of the qnr gene in clinical isolates of E. coli and K. pneumoniae from pediatric patients in China.MethodsA total 213 of non-repetitive clinical isolates resistant to ciprofloxacin from E. coli and K. pneumoniae were collected from hospitalized patients at five children's hospital in Beijing, Shanghai, Guangzhou, and Chongqing. The isolates were screened for the plasmid-mediated quinolone resistance genes of qnrA, qnrB, and qnrS by PCR. Transferability was examined by conjugation with the sodium azide-resistant E. coli J53. All qnr-positive were analyzed for clonality by enterobacterial repetitive intergenic consensus (ERIC)-PCR.ResultsThe study found that 19 ciprofloxacin-resistant clinical isolates of E. coli and K. pneumoniae were positive for the qnr gene, and most of the qnr positive strains were ESBL producers. Conjugation experiments showed that quinolone resitance could be transferred to recipients. Apart from this, different DNA banding patterns were obtained by ERIC-PCR from positive strains, which means that most of them were not clonally related.ConclusionThis report on transferable fluoroquinolone resistance due to the qnr gene among E. coli and K. pneumoniae strains indicated that plasmid-mediated quinolone resistance has emerged in pediatric patients in China.

High Prevalence and Significant Association of ESBL and QNR Genes in Pathogenic Klebsiella pneumoniae Isolates of Patients from Kolkata, India

“…In our samples, occurrence of bla genes was observed in the following order: bla TEM [ bla SHV [ bla CTX-M . Similar to our report QNR genes were less prevalent than bla genes among pathogenic bacteria in other countries [4,22,23]. Significant association between the presence of bla and QNR genes (as observed in the study) is of serious concern since quinolone resistant ESBL bacteria has limited treatment options.…”

Prevalence of qnr Genes and Antibiotic Susceptibility Patterns among Clinical Isolates of Klebsiella Pneumoniae in West of Iran

“…In contrast, in other investigations carried out in China and the USA, it has been shown that qnrS (14.9%) and qnrA (14%) are the most prevalent of all K. pneumoniae clinical isolates screened by multiplex PCR, respectively [16,18]. The present investigation shows no qnrA in its clinical isolates; similarly, Minarini et al [13] and Saiful et al [19] in Brazil and Malaysia have indicated no qnrA or qnrS-positive isolates among their clinical isolates of K. pneumonia, respectively.…”

“…Although the qnr gene indicates a low level of resistance to quinolones, its attendance aids the selection of chromosomal mutations, facilitating increased resistance in the host strain [9][10][11]. Frequency of qnr genes PMQR associated with the qnr genes in different human clinical enterobacterial isolates was determined first in the USA in 1994 using a K. pneumoniae isolate (later termed qnrA1) [9], which was then widely reported worldwide [12][13][14][15][16][17][18][19]. However, no study has been done on prevalence of qnr genes among enterobacterial clinical isolates in Iran.…”

Evaluation of Antibiotic Resistance Patterns of Clinical Klebsiella pneumoniae Isolates from Educational Hospitals in Zahedan, Iran

“…Lin J-C, Chang F-Y, Fung C-P, Xu J-Z, Cheng H-P, Wang J-J, et al fluoroquinolones (15,16). The excessive use of antibiotics has further increased the incidence of antibiotic resistance in bacteria, resulting in treatment failure, development of complications, and increased cost of treatment (17). Because of the genetic variations in the bacterial strains and the difference in the frequency of antibiotic use, a drug resistance rate varies widely in different regions of the world.…”