High prevalence of oxacillinases in clinical multidrug-resistant Acinetobacterbaumannii isolates from the Tshwane region, South Africa - an update

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dc.contributor.author Lowings, Michelle
dc.contributor.author Ehlers, M.M. (Marthie Magdaleen)
dc.contributor.author Dreyer, Andries W.
dc.contributor.author Kock, Marleen M.
dc.date.accessioned 2015-12-04T08:25:55Z
dc.date.available 2015-12-04T08:25:55Z
dc.date.issued 2015-11-14
dc.description.abstract BACKGROUND : Acinetobacter baumannii is an important hospital-acquired pathogen in healthcare facilities that frequently causes bacteraemia and ventilator-associated pneumonia in intensive care units. Acinetobacter baumannii can be isolated from various sites in the hospital environment like medical equipment, bed linen, medical personnel and indwelling catheters. It is difficult to treat A. baumannii infections because of their highly resistant antimicrobial profiles. The purpose of this study was to determine the prevalence of β-lactamase genes in multidrug-resistant (MDR) clinical A. baumannii isolates using Multiplex-PCR (M-PCR) assays. METHODS : One hundred MDR A. baumannii isolates were collected from the diagnostic division of the Department of Medical Microbiology after routine analysis of the submitted specimens. All collected isolates were identified and tested for susceptibility using the VITEK 2® system (bioMérieux, France). Six isolates were excluded from this study because the isolates were incorrectly identified as A. baumannii with the VITEK 2® system (bioMérieux, France). Molecular tests, namely M-PCR assays, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were performed. MLST analyses were performed on representative isolates from the four major pulsotypes (≥5 isolates with 80 % similarity) and selective isolates from each minor pulsotype. RESULTS : All the A. baumannii isolates showed 100 % resistance to ampicillin, amoxicillin, cefuroxime, cefuroximine axetil, cefoxitin, cefotaxime and nitrofurantoin. Seven percent of the isolates were resistant to amikacin. Two percent of the isolates were classified as having intermediate susceptibility to tigecycline. A. baumannii isolates showed an antibiotic resistance profile of 67 % and higher to antibiotics, such as ceftazidime, cefepime, imipenem, meropenem, gentamicin, ciprofloxacin and trimethoprim/sulfamethoxazole. None of the isolates were resistant to colistin. The M-PCR assays showed that 99 % of the isolates contained the OXA-51 gene and 77 % contained the OXA-23 gene. None of the isolates contained the GES, GIM, IMP, KPC, NDM, OXA-24, OXA-58, PER, SIM, SPM, VEB and VIM genes. Representative A. baumannii isolates were grouped into five existing sequence types (ST): ST106, ST258, ST339, ST502, ST758 and ST848. Isolates belonging to the pan-European clonal lineages I and II (EUI and EUII) were identified. CONCLUSION : The high prevalence of MDR A. baumannii isolates has a severe impact on available treatment choices and this in return impacts on treatment outcomes in the studied healthcare facilities. The most dominant ST among the collected isolates was ST758, member of the EUI group. The presence of the OXA-23 gene was not restricted to a specific ST. Continuous research and surveillance is necessary to monitor the circulating β-lactamase genes in clinical settings to guide infection control policies in order to try and curb the spread of this bacterium. en_ZA
dc.description.librarian am2015 en_ZA
dc.description.sponsorship ML was supported by a National Research Foundation (NRF) grant. The MALDI-TOF analysis is based on research supported in part by the National Research Foundation (NRF) of South Africa (Grant specific unique reference number (UID) 74426). en_ZA
dc.description.uri http://www.biomedcentral.com/bmcinfectdis/ en_ZA
dc.identifier.citation Lowings, M Ehlers, MM, Dreyer, AW & Kock, MM 2015, 'High prevalence of oxacillinases in clinical multidrug-resistant Acinetobacterbaumannii isolates from the Tshwane region, South Africa - an update', BMC Infectious Diseases, vol. 15, art. no. 521, pp. 1-10. en_ZA
dc.identifier.issn 1471-2334
dc.identifier.other 10.1186/s12879-015-1246-8
dc.identifier.uri http://hdl.handle.net/2263/51072
dc.language.iso en en_ZA
dc.publisher BioMed Central en_ZA
dc.rights © 2015 Lowings et al. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License. en_ZA
dc.subject Acinetobacter baumannii en_ZA
dc.subject Beta-lactamases en_ZA
dc.subject Multidrug-resistant (MDR) en_ZA
dc.subject Multiplex polymerase chain reaction (M-PCR) en_ZA
dc.subject Pulsed-field gel electrophoresis (PFGE) en_ZA
dc.subject Multilocus sequence typing (MLST) en_ZA
dc.title High prevalence of oxacillinases in clinical multidrug-resistant Acinetobacterbaumannii isolates from the Tshwane region, South Africa - an update en_ZA
dc.type Article en_ZA


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