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Objecfive To investigate antibiotic resistance,carbapenemase genotype and the molecular epidemiology of multidrug-resistant Acinetobacter baumannii (Aba) collected from 3 military hospitals in China.Methotis The minimum inhibitory concentrations (MIC) were examined by ager dilution method.Genotypes of carbapenemases were amplified by multiplex PCR and its products were sequenced.PCR was used to detect per gene,Homology of the resistant isolates was analyzed by pulse-field gel electrophoresis(PFGE).Results Among the 64 MDRA strains,78.1%(50)strains possessed blaOXA-23 gene,89.1%(57) carried Class 1 integrase gene,39.1% (25) with blaPER-1 gene,and 1 strain with blaOXA-58-like gene.PFGE showed that 13(A,B,C,D,E genotype) different clones were identified in these strains.A,B,and U clones were the predominant clones in three hospitals,respectitively.Conclusion OutbreaEs of muitidrug-rcsistant Aba occurred at 3 military hospitals with the most prevalent carbapenemase as OXA-23 enzyme.OXA-58 type of carbapenemase and per-1 in Aba were also isolated.
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<p><b>OBJECTIVE</b>To study the mode of transmission and molecular characteristics on carbapenem-resistant Acinetobacter baumannii strain. Strains were isolated from different parts of samples in various patients.</p><p><b>METHODS</b>Clinical information of carbapenem-resistant Acinetobacter baumannii isolates were stored and analyzed by WHONET 5.4 software. The transmission and pathopoiesis of the strains were learned through case file review. Genotypes of isolates were identified by pulse-field gel electrophoresis (PFGE) and genes of carbapenemase were detected by multiple PCR, in order to find molecular characteristics and relatedness between strains.</p><p><b>RESULTS</b>29 stains of Acinetobacter baumannii resistant to carbapenem were isolated from 2 or more kinds of samples among 13 patients'. Two genotypes were identified by PFGE: genotype A was obtained from 22 isolates in 11 patients and genotype B was obtained from 7 isolates in 4 patients. PCR amplification showed that all strains possessed OXA-23 gene except 1, and all strains possessed Integrase gene I except 3.</p><p><b>CONCLUSION</b>There were 2 different genotypes from 29 strains of carbapenem-resistant Acinetobacter baumannii with Genotype A as the main type. OXA-23 carbapenemase gene and integrase gene I were detected from most of the isolates. All the strains could be easily transmitted in the body of the patients and among patients, hence becoming the epidemic pathogen of iatrogenic infection.</p>
Subject(s)
Humans , Acinetobacter Infections , Microbiology , Acinetobacter baumannii , Classification , Genetics , Carbapenems , Pharmacology , Cross Infection , Microbiology , Drug Resistance, Bacterial , Genetics , GenotypeABSTRACT
Objective To study the AmpC beta-lactarnase and its genotype mediated by plasmid in Escherichia coli.Methods AmpC beta-lactamase was detected based on that AmpC beta-laetamase can be inhibited by 3-aminophenylboronic acid(APB).MIC was ehecked by agar dilution method.Conjugation test was used to check the transfer of ampC gene.Gene chip and PCR were used to detect ampC gene.The amplified ampC gene were sequenced and analyzed by EMBOSS software.The molecular epidemiology of clinical isolates was investigated by Enterbacterial repetitive intergenic consensus(ERIC)typing method.Results In 74 strains of Escherichia coli insusceptible to cefoxtin,AmpC beta-lactamase was positive in 33 strains.8 strains possessed AmpC beta-lactamase of CIT group by gene chip and 8 transconjugants were obtained by conjugation test.CMY type ampC gene could be further amplified by specific CMY gene primers from both 8 clinical isolates of E.coli and plasmids extracted from 8 transconjugants.CMY-2 type ampC gene was found by sequencing(accession number DQ823449).The most transconjugants displayed similar MIC value(intermediate or resistant).ERIC genotyping showed 6 out of 8 isolates with CMY-2 ampC gene derived from different resource.Conclusion CMY-2 AmpC beta- lactamase mediated by plasmid could be detected in E.coli isolates from patients in the General Hospital of People Liberation Army,Beijing.The plasmid carried ampC gene could mediate multi-drug resistance.