title: Emergence of Multidrug Resistance and Metallo-beta-lactamase Producing Acinetobacter baumannii Isolated from Patients in Shiraz, Iran.
abstract: BACKGROUND
  Metallo-beta-lactamase (MβL) enzymes production is one of the most important resistance mechanisms against carbapenems in some bacteria including Acinetobacter baumannii.
  
  
  OBJECTIVE
  This study was aimed to determine the antimicrobial susceptibility and the prevalence of MβL among carbapenem-resistant isolates of A. baumannii.
  
  
  METHODS
  In this cross-sectional study from October 2012 to April 2013, 98 isolates were identified as A. baumannii using Microgen™ kits and confirmed by molecular method. These isolates were tested for antimicrobial susceptibilities by disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines. Carbapenem-resistant isolates were further detected phenotypically by MβL minimal inhibitory concentration (MIC)-test strips, and subsequently positive MβL isolates were confirmed by polymerase chain reaction (PCR).
  
  
  RESULTS
  Overall, 98% (96/98) of A. baumannii isolates were detected as carbapenem-resistant by MIC test. Highest sensitivity to the tested antibiotic with 42.9% (42/98) was observed to colistin. Of 96 carbapenem-resistant isolates, 43 were phenotypically positive for MβL; out of 43 isolates, 37 were confirmed for the presence of MβL genes by PCR.
  
  
  CONCLUSIONS
  The frequency of drug resistance among the clinical samples of A. baumannii isolated in our study against most of the antibiotics was very high. Moreover, all MβL producing isolates were multidrug resistance. Therefore, systematic surveillance to detect MβL producing bacteria and rational prescription and use of carbapenems could be helpful to prevent the spread of carbapenem resistance.
authors.affiliation: Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: M N
authors.initials: MN
authors.lastname: Moghadam
authors.affiliation: Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran; Shiraz HIV/AIDS Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Motamedifar
authors.affiliation: Shiraz HIV/AIDS Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: J
authors.initials: J
authors.lastname: Sarvari
authors.affiliation: Shiraz HIV/AIDS Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Ebrahim-Saraie H
authors.initials: ES
authors.lastname: Sedigh
authors.affiliation: Shiraz HIV/AIDS Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Same M
authors.initials: SM
authors.lastname: Mousavi
authors.affiliation: Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: F N
authors.initials: FN
authors.lastname: Moghadam
keywords: Acinetobacter baumannii; Antibiotic resistance; Carbapenem; Iran; Metallo-beta-lactamase