title: Prevalence of CTX-M resistance marker and integrons among Escherichia coli and Klebsiella pneumoniae isolates of clinical origin.
abstract: Bacterial pathogens producing CTX-M beta-lactamases are emerging around the world as a source of resistance to oxyimino cephalosporins such as cefotaxime. In this study, we have investigated the prevalence of blaCTX-M genes among clinical isolates of Escherichia coli and Klebsiella pneumoniae. Of the double-disk synergy test-positive E. coli (n = 94) and Kl. pneumoniae (n = 73) strains isolated during the study period, 41 (44·08%) E. coli and 32 (43·24%) Kl. pneumoniae isolates were found to be positive for blaCTX-M genes. Twenty-two integrons (13 for E. coli and 9 for Kl. pneumoniae) were detected whose sizes ranged from 600 bp to 1·5 kb. All these integrons were found to be of Class1 type and were invariably PCR positive for int1 and sul1 genes. Marker transfer experiments demonstrated plasmid-mediated transfer of cefotaxime and ceftazidime resistance markers. In addition, analysis of the enterobacterial repetitive intergenic consensus (ERIC)-PCR typing of the blaCTX-M -carrying isolates showed that they were genetically diverse and heterogeneous suggesting that multiple subtypes of the species were involved in infection.
  
  
  CONCLUSIONS
  A high frequency of blaCTX-M -resistant marker has been found in Escherichia coli and Klebsiella pneumoniae isolates of clinical origin. Analysis of the ERIC-PCR typing of the blaCTX-M -carrying isolates showed that they were genetically diverse and heterogeneous suggesting that multiple subtypes of the species were involved in infection.
authors.affiliation: Department of Biosciences, Integral University, Lucknow, India.
authors.forename: S
authors.initials: S
authors.lastname: Shaikh
authors.affiliation: Department of Biosciences, Integral University, Lucknow, India.
authors.forename: S M D
authors.initials: SM
authors.lastname: Rizvi
authors.affiliation: Department of Bio-engineering, Integral University, Lucknow, India.
authors.forename: R
authors.initials: R
authors.lastname: Anis
authors.affiliation: KACST Technology Innovation Center for Personalized Medicine at King Abdulaziz University, Jeddah, Saudi Arabia.|Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: S
authors.initials: S
authors.lastname: Shakil
mesh_terms: D002439:Cefotaxime / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics*; D006801:Humans; D032023:Integrons / Q000235:genetics*; D007710:Klebsiella Infections / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D058889:Molecular Typing; D015995:Prevalence; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D029968:Escherichia coli Proteins; D001618:beta-Lactamases; C000602253:beta-lactamase CTX-M, E coli; D002439:Cefotaxime
keywords: CTX-M beta-lactamases; Class 1 integrons; ERIC-PCR; Escherichia coli; Klebsiella pneumoniae; genotypic method