title: Diversity of β-lactamases produced by imipenem resistant, Pseudomonas aeruginosa isolates from the bloodstream.
abstract: BACKGROUND
  The emergence of imipenem non-susceptible Pseudomonas aeruginosa isolates is a matter of great concern because these isolates can become resistant to all available antibiotics. This study conducted to characterize β-lactamase genes in imipenem resistant P. aeruginosa isolates from bloodstream.
  
  
  METHODS
  56 non-duplicate clinical isolates of P. aeruginosa were collected in Tehran hospitals. Antibacterial susceptibility was determined by disk diffusion and MIC methods. ESBL and MBL production was confirmed by combined disk. β-Lactamase classes A, B and D genes were identified by PCR.
  
  
  RESULTS
  Seventeen (30.3%) isolates were imipenem resistant for which 16 isolates simultaneously were resistant to all tested antibiotics. While among 39 imipenem susceptible isolates, only two isolates were resistant to all tested antibiotics. In imipenem resistant isolates, blaTEM, blaSHV and blaOXA-10 were found in 41.1% of isolates and blaVIM, blaIMP and blaPER were identified in 47%, 11.7% and 5.8% of isolates respectively, while in imipenem susceptible isolates, blaTEM, blaSHV and blaOXA-10 were determined in 2.5%, 7.6% and 33.3% of isolates, respectively. The imipenem resistant isolates had been recovered mostly (67.7%) from patients in the Burn hospital.
  
  
  CONCLUSIONS
  The result of this study indicated the emergence of multidrug resistant MBL and non-MBL producing P. aeruginosa, particularly in the Burn hospital and blaVIM was dominant β-lactamase genes in imipenem resistant isolates. The isolation of carrier patients may lead to prevent a further dissemination.
authors: Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. Electronic address: najarp_s@modares.ac.ir.
authors: Shahin
authors: S
authors: Najar Peerayeh
authors: Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. Electronic address: Rahim-Pirhajati@yahoo.com.
authors: Rahim
authors: R
authors: Pirhajati Mahabadi
authors: Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. Electronic address: sanaz_pakbaten@yahoo.com.
authors: Sanaz
authors: S
authors: Pakbaten Toupkanlou
authors: Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran. Electronic address: d.siadat@gmail.com.
authors: Seyed Davar
authors: SD
authors: Siadat
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000382:microbiology*; D002648:Child; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D005260:Female; D006801:Humans; D015378:Imipenem / Q000494:pharmacology*; D007492:Iran; D008297:Male; D008826:Microbial Sensitivity Tests; D011552:Pseudomonas Infections / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D015378:Imipenem; D001618:beta-Lactamases
keywords: Metallo β-lactamase; Pseudomonas aeruginosa; bla(OXA-10); bla(SHV); bla(TEM)