Outbreaks of Imipenem Resistant Acinetobacter Baumannii Producing OXA-23 β-Lactamase in a Tertiary Care Hospital in Korea

Abstract

PurposeSince 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 MethodsForty-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-β-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.ResultsAll 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.ConclusionIt 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.

Spread of carbapenem-resistant international clones of Acinetobacter baumannii in Turkey and Azerbaijan: a collaborative study

“…Many studies [8,[10][11][12] on A. baumannii nosocomial infection reported the co-existence of OXA-23 together with OXA-51 in most isolates of this species, corresponding with this study, in which OXA-23 was the most prevalent carbapenemase among all carbapenem-resistant isolates. The results of this study supported the proposal that bla OXA-51-like genes are detected in A. baumannii and Acinetobacter nosocomialis strains.…”

High burden of antimicrobial resistance in Asia

“…In sharp contrast to non-baumannii Acinetobacter spp., oxacillinase (Ambler class D ␤-lactamase) genes, located on plasmids and downstream from insertion sequence ISAba3 and IS1008 (two promoters for transcriptional control of bla OXA genes), were shown to play an important role in conferring non-susceptibility to imipenem in A. baumannii isolates in Taiwan [61]. The most prevalent disseminated class D oxacillinase amongst A. baumannii in China and Korea is OXA-23 [62,63], whereas in Taiwan the most prevalent are OXA-58-like and OXA-24-like ␤-lactamases [61]. High rates of resistance of A. baumannii to colistin and polymyxin B (27.9% and 18.1%, respectively) have been noted in Korea [64], which contrasts markedly with the rates of resistance of strains in Taiwan [9,61].…”

Evolución de la resistencia antimicrobiana de bacilos Gram negativos en unidades de cuidados intensivos en Colombia

“…La OXA-23 en A. baumannii fue la carbapenemasa más frecuentemente detectada en el país; esta enzima contribuye al perfil de multirresistencia, el cual podría estar incrementado por la presencia de brotes hospitalarios (40)(41)(42).…”