title: Comparison between phenotypic and PCR for detection of OXA-23 type and metallo-beta-lactamases producer Acinetobacter spp.
abstract: BACKGROUND
  Resistance to carbapenems is developing around the world and can cause many problems for treatment of patients. Production of metallo-beta-lactamase (MBL) is one of the main mechanism for this type of resistance. So, detection of MBL-producer microorganisms can prevent the spread of this type of resistance.
  
  
  METHODS
  In this study 94 Acinetobacter spp. were investigated. Resistance to imipenem was conducted after purification and identification. Combination disc (CD) and Double Disc Synergy Test (DDST) were performed for phenotypic detection of MBL and the molecular PCR method was done for vim-1, vim-2, imp-1 and OXA-23 genes.
  
  
  RESULTS
  According to TSI, SIM and oxidation-fermentation (OF) test and PCR assay 93 Acinetobacter baumannii and one strain Acinetobacter lwoffii were identified. 85% of them were resistant to imipenem. 34% of them have a positive combination disc test (CD) while Double Disc Synergy Test (DDST) was negative for all of them. The vim-1, vim-2 and imp-1 genes were not detected in PCR molecular method, however in 74% of strains with positive results in combination disc, were positive for the OXA-23 gene after PCR test. This study shows that the blaOXA-23 resistance determinant may become an emerging therapeutic problem.
  
  
  CONCLUSIONS
  According to the results, it seems that combination disc does not have enough specificity for detection of MBL-producer Acinetobacter and using Double Disc Synergy Test (DDST) can be more convenient.
authors: Antimicrobial Resistance Research Center, Iran University of Medical Sciences, Tehran, Iran.
authors: Leila
authors: L
authors: Azimi
authors: Abdolaziz Rastegar
authors: AR
authors: Lari
authors: Malihe
authors: M
authors: Talebi
authors: Amirmorteza Ebrahimzadeh
authors: AE
authors: Namvar
authors: Mosadegh
authors: M
authors: Jabbari
keywords: Acinetobacter; Double Disc Synergy Test; OXA23; combination disc Test; metallo-beta-lactamase