Outbreak of carbapenem-resistant Acinetobacter baumannii carrying the carbapenemase OXA-23 in a German university medical centre

Abstract

A prolonged outbreak of carbapenem-resistant Acinetobacter baumannii in a German university medical centre in 2006 was investigated; the investigation included a descriptive epidemiological analysis, a case-control study, environmental sampling, molecular typing of A. baumannii isolates using PFGE and repetitive-sequence-based PCR (rep-PCR) typing, and detection of OXA-type carbapenemases by multiplex PCR. Thirty-two patients acquired the outbreak strain in five intensive care units (ICUs) and two regular wards at a tertiary care hospital within 10 months. The outbreak strain was resistant to penicillins, cephalosporins, ciprofloxacin, gentamicin, tobramycin, imipenem and meropenem, and carried the bla OXA-23 -like gene. Based on PFGE and rep-PCR typing, it was shown to be related to the pan-European A. baumannii clone II. The most likely mode of transmission was cross-transmission from colonized or infected patients via the hands of health-care workers, with the severity of disease and intensity of care (therapeutic intervention scoring system 28 score .median) being independently associated with acquisition of the outbreak strain (odds ratio 6.67, 95 % confidence interval 1. 55-36.56). Control of the outbreak was achieved by enforcement of standard precautions, education of personnel, screening of ICU patients for carbapenem-resistant A. baumannii and cohorting of patients. This is believed to be the first report of an outbreak of A. baumannii carrying the carbapenemase OXA-23 in Germany.

Interlaboratory reproducibility of DiversiLab rep-PCR typing and clustering of Acinetobacter baumannii isolates

“…Rep-PCR typing was performed using the DiversiLab Acinetobacter kit (bioMérieux). DNA isolation and rep-PCR of the whole set of isolates were each performed separately in the two laboratories from isolates grown overnight on solid medium following the manufacturer's instructions as previously reported (Perez et al, 2010;Endimiani et al, 2009;Kohlenberg et al, 2009;Higgins et al, 2010). However, owing to problems observed in the Cologne laboratory with both DNA yield and quality using the UltraClean Microbial DNA Isolation kit (MO BIO Laboratories) that is recommended by the manufacturer, DNA isolation in Cologne was performed using the Qiagen DNeasy kit (Qiagen) whereas the Cleveland laboratory used the MO BIO kit.…”

“…Rep-PCR libraries can therefore be easily assembled to enable, for example, the comparison of strains over time and probably across laboratories, with a view to charting the epidemiology of isolates. Outbreaks of Acinetobacter baumannii have been extensively studied using DiversiLab rep-PCR typing (Carretto et al, 2008;Fontana et al, 2008;Kohlenberg et al, 2009;Yan et al, 2010;Perez et al, 2010). Using DiversiLab, a snapshot emerged of the global epidemiology of carbapenem-resistant A. baumannii, where it was found that almost half of 492 isolates from a worldwide collection belonged to a single clonal lineage that clustered with European clone II (Higgins et al, 2010;Dijkshoorn et al, 1996).…”

Increasing imipenem resistance and dissemination of the ISAba1-associated bla OXA-23 gene among Acinetobacter baumannii isolates in an intensive care unit

“…The bla OXA-23 gene, increasingly reported worldwide (Kohlenberg et al, 2009;Mugnier et al, 2010;Stoeva et al, 2008;Wang et al, 2007;Zhou et al, 2007), was the most prevalent (97/98, 99.0 %) acquired carbapenemase gene among 98 imipenem-resistant A. baumannii isolates, which is different from the result of a recent study showing that the bla OXA-58-like gene was epidemic in several Italian ICUs (Donnarumma et al, 2010). In addition, the presence of the ISAba1 element and its association with bla OXA-23 was identified among all the bla OXA-23 -positive isolates.…”

First Report of the blaOXA-23 Gene in a Clinical Isolates of Acinetobacter baumannii in Najaf Hospitals-Iraq

“…Resistance to this antibiotic has emerged due to the production carbapenem-hydrolyzing enzyme (carbapenemases) among A. baumannii (Kohlenberg et al, 2009). Moreover, the resistance to carbapenems may involve several combined mechanisms other than carbapenemases, include modifications to outer membrane permeability and hyperproduction of AmpC β-lactamases (Nordmann et al, 2009).…”

“…Phenotypic screening for carbapenemase production confirmed that 4 (33.3%) A. baumannii isolates were carbapenemase producer by both methods ( Table 2). The main enzymes may involve in carbapenem resistance are OXA-carbapenemases (Kohlenberg et al, 2009).…”