Molecular characteristics and resistant mechanisms of imipenem-resistant Acinetobacter baumannii isolates in Shenyang, China
| Autor: | Bai Yi Chen, Jingping Zhang, Yun Zhuo Chu, Su Fei Tian, Wan Zhu |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Acinetobacter baumannii
China Imipenem Genotype medicine.medical_treatment Microbial Sensitivity Tests Integron Applied Microbiology and Biotechnology Microbiology beta-Lactamases Integrons Drug Resistance Bacterial polycyclic compounds Pulsed-field gel electrophoresis medicine Cluster Analysis Humans Molecular Epidemiology Molecular epidemiology biology General Medicine biochemical phenomena metabolism and nutrition bacterial infections and mycoses biology.organism_classification DNA Fingerprinting Anti-Bacterial Agents Bacterial Typing Techniques Electrophoresis Gel Pulsed-Field Beta-lactamase biology.protein Multilocus sequence typing Acinetobacter Infections Multilocus Sequence Typing medicine.drug |
| Zdroj: | The Journal of Microbiology. 48:689-694 |
| ISSN: | 1976-3794 1225-8873 |
| Popis: | The investigation was carried out to elucidate the molecular characteristics and resistant mechanisms of imipenem-resistant Acinetobacter baumannii. Thirty-seven isolates were collected from January 2007 to December 2007. The homology of the isolates was analyzed by both pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The genes of β-lactamases, adeB, and class 1 integron were polymerase chain reaction amplified. Genotype analysis of the 37 A. baumannii isolates by PFGE revealed the circulation of four PFGE types (A-D); the A- and B-type accounted for 48.6% and 40.5%, respectively. MLST showed the existence of three allelic profiles. The agar dilution method was carried out to determine the MIC of imipenem, in the absence or presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP, 10 μg/ml). The MICs of the strains to imipenem were between 16 μg/ml and 128 μg/ml. When CCCP was added, a MIC decrease of at least four-fold was observed in 20 isolates, which belonged to the A- or C-type. AdeB and bla (PER-1) genes were each detected in 35 isolates, bla (OXA-23) gene in 34 isolates and bla (OXA-58)-like gene in 24 isolates. All isolates harbored bla (OXA-51)-like genes. No isolates carried the bla (IMP-1) gene. Integron was detected in 25 isolates, which mediated the resistance to aminoglycosides and rifampin. The epidemiologic data suggested that the increasing infection of A. baumannii in our hospital was mainly caused by the inter-hospital spread of two epidemic clones. The AdeABC efflux system may be the important factor that leads to the high level of imipenem-resistance in PFGE A-type. |
| Databáze: | OpenAIRE |
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