title: bla(IMP) and bla(VIM) mediated carbapenem resistance in Pseudomonas and Acinetobacter species in India.
abstract: BACKGROUND
  The emergence and rapid spread of blaIMP and blaVIM metallo-beta-lactamase (MBL) producing Gram-negative bacteria causing nosocomial infections are of concern worldwide due to limited treatment options.
  
  
  METHODS
  A total of 179 nonreplicate, consecutive, carbapenem resistant Pseudomonas aeruginosa (61), Acinetobacter baumannii (116), Acinetobacter lwoffii (1) and Pseudomonas stutzeri (1) isolated from patients hospitalized for 48 hours or more were included in the study. The minimum inhibitory concentrations (MIC) to imipenem and meropenem were determined and interpreted according to Clinical Laboratory Standards Institute guidelines. The Modified Hodge Test (MHT) and inhibitor potentiated disk diffusion tests with ethylenediaminetetraacetic acid (EDTA) were used for screening of carbapenamases and MBL production respectively. Polymerase chain reaction (PCR) was performed for the detection of MBL (blaVIM and blaIMP) genes. Gene sequencing was performed for representative isolates.
  
  
  RESULTS
  MHT was positive in 94.4% (n = 169). MBL screening with EDTA was positive in 80.4% (n = 144). MBL genes bla VIM and bla IMP were detected in 92 (51.4%) isolates. Bla VIM alone was detected in 89 isolates while two isolates had bla IMP alone. One isolate had both bla VIM and bla IMP. Among the P. aeruginosa, 36 carried the MBL gene. In A. baumannii, 54 carried the MBL gene. Bla VIM was found in P. stutzeri and A. lwoffii isolates.
  
  
  CONCLUSIONS
  Carbapenem resistance in P. aeruginosa and A. baumannii is chiefly mediated by MBL production. The common MBL gene is the blaVIM.
authors.affiliation: Sri Ramachandra Medical College and Research Institute, Porur, Chennai, India. amu_shanthi@yahoo.co.in
authors.forename: M Shanthi
authors.initials: MS
authors.lastname: Amudhan
authors.forename: Uma
authors.initials: U
authors.lastname: Sekar
authors.forename: Arunagiri
authors.initials: A
authors.lastname: Kamalanathan
authors.forename: Sekar
authors.initials: S
authors.lastname: Balaraman
mesh_terms: D000150:Acinetobacter / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D000151:Acinetobacter Infections / Q000382:microbiology; D000583:Amikacin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D052978:Disk Diffusion Antimicrobial Tests; D024881:Drug Resistance, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D015378:Imipenem / Q000494:pharmacology*; D007194:India; D007362:Intensive Care Units; D000077731:Meropenem; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011549:Pseudomonas / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D011552:Pseudomonas Infections / Q000382:microbiology; D013845:Thienamycins / Q000494:pharmacology; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D013845:Thienamycins; D015378:Imipenem; D000583:Amikacin; D001618:beta-Lactamases; D000077731:Meropenem