Carbapenem resistance in Acinetobacter baumannii is a growing public health
concern and represents a serious problem for treatment of the infection. Several
carbapenem-hydrolysing &beta / -lactamases have been identified from A. baumannii so far.
In this study carbapenem resistance in A.baumannii strains recovered from intensive
care units of Gulhane Military Medical Academy, Turkey, were investigated via
multiplex PCR and with parallel phenotypic tests. From June 2006 to January 2010,
138 clinical A. baumannii isolates were collected. Identification and antimicrobial
susceptibility tests of the isolates were performed. The MICs of imipenem and
meropenem were determined by using E-test method. Carbapenem resistant A.
baumannii strains were included for further study. Firstly, the presence of carbapenemases were determined. The presence of Metallo-beta-lactamase (MBL)
were also investigated. Detection of the four groups of OXA carbapenemases (OXA-
23, OXA-24, OXA-51 and OXA-58) was carried out using a multiplex PCR assay.
Sequence analyses were performed. Non-duplicate, multidrug resistant 61 clinical A.
baumannii isolates were found to be resistant to imipenem and meropenem. In the 61
isolates, the MIC50 of imipenem and meropenem were 16 and > / 32 / MIC90 were 192
and > / 32 respectively. Modified Hodge Tests (MHT) were positive for all 61 A.
baumannii strains. None of these isolates showed MBL activity. As determined
through multiplex PCR, all of the 61 isolates had blaOXA-51 genes, 50 isolates had
blaOXA-23, and 11 isolated had blaOXA-58 genes. Alleles encoding OXA-24-like
enzymes were not detected in any isolates. This study indicated that the clinical
isolates in our region contained blaOXA-51, blaOXA-23, and blaOXA-58 resistance genes.
However, blaOXA-24 gene was either absent or occur in very low frequency.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12613061/index.pdf |
| Date | 01 February 2011 |
| Creators | Uskudar Guclu, Aylin |
| Contributors | Gozen, Ayse Gul |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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