Molecular characterization of multidrug-resistant extended-spectrum β-lactamase-producing Enterobacteriaceae isolated in Antananarivo, Madagascar

BMC Microbiol. 2013 Apr 17;13:85. doi: 10.1186/1471-2180-13-85.

Abstract

Background: We investigated the molecular characteristics of multidrug-resistant, extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae isolated in community settings and in hospitals in Antananarivo, Madagascar.

Results: Forty-nine E. coli, K. pneumoniae, K. oxytoca and E. cloacae ESBL-producing isolates were studied. In antimicrobial susceptibility analyses, many of the isolates exhibited resistance to aminoglycosides, fluoroquinolones and trimethoprim-sulfamethoxazole. Gene amplification analysis and sequencing revealed that 75.5% (n=37) of the isolates harbored blaCTX-M-15 and 38.7% (n=19) harbored blaSHV-12. The non-ESBLs resistance genes detected were blaTEM-1, blaOXA-1, aac(6')-Ib,aac(6')-Ib-cr, tetA, sul-1, sul-2, qnrA, qnrB and catB-3. We found dfrA and aadA gene cassettes in the class 1 integron variable regions of the isolates, and the combination of dfrA17-aadA5 to be the most prevalent. All blaCTX-M-15 positive isolates also contained the ISEcp1 insertion element. Conjugation and transformation experiments indicated that 70.3% of the antibiotic resistance genes resided on plasmids. Through a PCR based replicon typing method, plasmids carrying the blaSHV-12 or blaCTX-M-15 genes were assigned to either the IncFII replicon type or, rarely, to the HI2 replicon type. All isolates were subtyped by the rep-PCR and ERIC-PCR methods.Phylogenetic grouping and virulence genotyping of the E. coli isolates revealed that most of them belonged to group A1. One isolate assigned to group B2 harbored blaCTX-M-15 and five virulence genes (traT, fyuA, iutA, iha and sfa) and was related to the O25b-ST131 clone.

Conclusions: Our results highlight the dissemination of multidrug resistant Enterobacteriaceae isolates in Antananarivo. These findings underline the need for a rational use of antibiotic and for appropriate methods of screening ESBL in routine laboratories in Antananarivo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Cluster Analysis
  • Community-Acquired Infections / epidemiology
  • Community-Acquired Infections / microbiology
  • Conjugation, Genetic
  • Cross Infection / epidemiology
  • Cross Infection / microbiology
  • Drug Resistance, Multiple, Bacterial*
  • Enterobacteriaceae / drug effects
  • Enterobacteriaceae / enzymology*
  • Enterobacteriaceae / genetics*
  • Enterobacteriaceae / isolation & purification
  • Enterobacteriaceae Infections / epidemiology
  • Enterobacteriaceae Infections / microbiology*
  • Genes, Bacterial
  • Humans
  • Integrons
  • Madagascar / epidemiology
  • Microbial Sensitivity Tests
  • Molecular Epidemiology
  • Molecular Typing
  • Phylogeny
  • Plasmids / analysis
  • Plasmids / classification
  • Polymerase Chain Reaction
  • Sequence Analysis, DNA
  • Transformation, Bacterial
  • beta-Lactamases / genetics
  • beta-Lactamases / metabolism*

Substances

  • Anti-Bacterial Agents
  • beta-Lactamases