ABSTRACT
PURPOSE: Since November 2006, imipenem-resistant Acinetobacter baumannii isolates have increased in Kyung Hee University Hospital in Seoul, Korea. The purpose of this study was to determine the genetic basis and molecular epidemiology of outbreak isolates. MATERIALS AND METHODS: Forty-nine non-repetitive isolates of the 734 IRAB strains were investigated in order to determine their characteristics. The modified Hodge and the ethylenediaminetetraacetic acid (EDTA)-disk synergy test were performed for the screening of carbapenemase and metallo-beta-lactamase production. Multiplex polymerase chain reaction (PCR) assays were performed for the detection of genes encoding for OXA-23-like, OXA-24-like, OXA-58-like and OXA-51-like carbapenemase. Pulsed-field gel electrophoresis (PFGE) was performed for strain identification. RESULTS: All isolates showed 100% resistance to ciprofloxacin and gentamicin, 97.9% resistance to cefepime, piperacillin/tazobactam, aztreonam, ceftazidime and piperacillin, 93.9% resistance to tobramycin and 57.1% resistance to amikacin. All of the 49 isolates (100%) showed positive results in the modified Hodge test and negative results in the EDTA-disk synergy test. They all (100%) possessed the encoding gene for an intrinsic OXA-51-like carbapenemase and an acquired OXA-23-like carbapenemase in the multiplex PCR assay. PFGE patterns revealed that all isolates were clonally related from A1 to A14. CONCLUSION: It is concluded that all of the 49 IRAB isolates acquired resistance to imipenem by producing OXA-23 carbapenemase and they might have originated from a common source.
Subject(s)
Humans , Acinetobacter Infections/epidemiology , Acinetobacter baumannii/drug effects , Anti-Bacterial Agents/pharmacology , Cephalosporins/pharmacology , Ciprofloxacin/pharmacology , Disease Outbreaks , Drug Resistance, Multiple, Bacterial/genetics , Electrophoresis, Gel, Pulsed-Field , Gentamicins/pharmacology , Imipenem/pharmacology , Korea/epidemiology , Microbial Sensitivity Tests , beta-Lactamases/genetics , beta-Lactams/pharmacologyABSTRACT
85%of IRAB were resistant to the rest 12 antibacterials except polymyxin B,cefoperazone/sulbactam and minocycline.CONCLUSIONS It should be exactly detect and control IRAB due to extremely severity about hospital infections and multidrug resistantce.