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To investigate the molecular epidemiological characteristics of Staphylococcus aureus associated with bloodstream infection in hospital.47 Staphylococcus aureus strains isolated from bloodstream in PLA General Hospital were collected from January 2006 to December 2008. Susceptibility of the strains to 11 antimicrobial agents was detected and DNA homology of them was analyzed with Rep-based DiversiLab(TM) Microbial Typing System. Panton-Valentine leukocidin (PVL) gene was determined by PCR. For methicillin-resistant Staphylococcus aureus (MRSA) strains, the genotypes of SCCmec were determined and ST239 clone was screened with multiplex PCR. Multilocus sequence typing (MLST) was used to determine the STs of the selected isolates.In the 47 Staphylococcus aureus isolated from blood, methicillin-resistant strains accounted for 51.1%, all belonged to SCCmec III type, with only 2 pvl gene positive strains identified. 12 different patterns (A-L) were found among 47 strains with Rep-PCR. All MRSA strains clustered in the A and B subtypes.Most MRSA strains isolated from blood in PLA General Hospital belonged to ST239-MRSA-SCCmec III clone. DiversiLab(TM) Microbial Typing System could provide a rapid and effective method to investigate the molecular epidemiological characteristics of Staphylococcus aureus in the hospital settings.

To investigate antibiotic resistance, carbapenemase genotype and the molecular epidemiology of multidrug-resistant Acinetobacter baumannii (Aba) collected from 3 military hospitals in China.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).Among the 64 MDRA strains, 78.1% (50) strains possessed bla(OXA-23) gene, 89.1% (57) carried Class 1 integrase gene, 39.1% (25) with bla(PER-1) gene, and 1 strain with bla(OXA-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.Outbreaks of multidrug-resistant 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.

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.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.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.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.