Late-breaking abstract: Molecular and phenotypic characters of methicillin-resistant staphylococcus aureus isolates from patients with empyema thoracis in Central Taiwan

Background: Staphylococcus aureus had been isolated from patients with severe infections and empyema. . The goals were to delineate the molecular and phenotypic characters of MRSA isolated from patients with empyema thoracis.in central taiwan Methods : MRSA isolates from pleural effusion of patients with empyema were collected from March, 2012 to Feb, 2014 and were typed with PCR and nucleotide sequencing based on polymorphisms in staphylococcal cassette chromosome , multilocus sequence type , X region on protein A ( spa ), and direct repeat units . Phenotypes were characterized with antibiogram by disc diffusion and MIC to vancomycin by agar dilution. Results : Totally 19 non-duplicate MRSA isolates with mecA from patients with empyema were analyzed. The mean and range of MIC to VA were 2.13 and 2 to 3 mg/L, respectively. Multidrug resistance, defined as resistance to more than or equal to 3 kinds of antibiotics other than ƒÀ-lactam by disc diffusion method, was found in 15 (78.9%) isolates. The isolates were typed as followed (no.%): ST5-SCC mec II- spa (6, 31.2%); ST239 and its SLV-SCC mec III- spa (6, 31.2%); SCC mec IV-ST573- spa (2, 10.5%), SCC mec IV-ST8 and its SLV- spa (2, 10.5%), ST59-SCC mec IV or V T - spa (2, 10.5%); and SCC mec V with untypable ST and spa types (1, 5.3%). Conclusions: Diverse molecular types with high rate of multidrug resistance and elevated MIC to vancomycin were found in 19 MRSA isolates from patient with empyema. Further attempts including Panton-Valentine leukocidin and superantigenic toxins identification will help in delineating the correlation between molecular types and phenotypes of MRSA in patients with empyema.