Molecular Typing and Phenotypes Characterization of Methicillin-Resistant Staphylococcus aureus From Patients With Empyema Thoracis

• Main Authors: Wan-Ting Chang, 張菀庭
• Other Authors: Bor-Show Tzang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/91568985542732608941

碩士 === 中山醫學大學 === 生化暨生物科技研究所 === 101 === Background: Staphylococcus aureus (S.aureus) can cause many serious infections, such as bacteremia, skin and soft tissue infections, pneumonia, osteoarthritis, and sepsis ,with high mortality rate and complication rate. Methicillin-Resistant S. aureus( MRSA) was discovered in the 1960s, has 60-80% of S. aureus belonging to MRSA in Taiwan. Literature has reported on Community- associated (CA-MRSA) and Healthcare- associated MRSA (HA-MRSA) is significantly different between genotyping and phenotype, and MRSA has a few specific clones in particular endemic. The purpose of this study is to investigate the cause of empyema by MRSA strains of genotype and phenotype of specificity and differences.Methods: Based on clinical criteria collected 23 specimens from pleural effusion isolated with methicillin-resistant Staphylococcus aureus (MRSA) strains of the following organisms phenotype and molecular typing of identification. Phenotype for the strain identification, drug susceptibility testing, minimum inhibitory concentration(MIC) of vancomycin by agar dilution method, induced macrolide-lincosamide-streptogramin B resistance testing (MLSBi, D-test), Panton-Valentine Leukocidin toxin gene (pvl),determination of staphylococcal enterotoxin (SEs) virulence factor gene; molecular biology typing is performed Staphylococcal cassette chromosome mec (SCCmec), multilocus sequence typing (MLST), Staphylococcal protein A (spa), accessory gene regulator (agr), and direct repeat units (dru). Results: From 23 patients with empyema isolated MRSA, confirmed by laboratory analysis was identified as 19 non-duplicate of MRSA. Drug susceptibility test results of approximately 74% of the MRSA strains are multidrug-resistant strains;the range of minimum inhibitory concentration (MIC) to vancomycin using the agar dilution method were 2-3mg / L;19 MRSA strains of the macrolide-lincosamide-streptogramin B resistance testing (MLSBi) were negative; pvl positive rate of only 16%; 19 MRSA strains can be classified into nine kinds of enterotoxins (SEs) virulence factor complex. HA-MRSA accounted for 68% (molecular biology typing to SCCmecII and SCCmecIII); CA-MRSA accounted for 32% (molecular biology typing to SCCmecIV and SCCmecVT). 19 specimens from pleural empyema patient isolation of non-duplicate MRSA strains were having mecA gene, and total of five main genetic groups： SCCmecII-ST5-spat002-dru4, SCCmecIII-ST239-spat037-dru14or12or15, SCCmecIV-ST59-spat437-dru9, SCCmecIV-ST573-spat3523-dru9or8or10, SCCmecVT-ST59-spat437-dru11；pvl gene related with SCCmecIV, ST59 andspat437; multidrug resistance (more than or equal to 4 kinds antibiotics) related with SCCmecII, ST5, spat002, dru4; MRSA strain with high vancomycin MIC is related with SCCmecIII, ST239, spat037 and agr group I；there is no any related between MLSBi and phenotyping or genotyping；the 19 isolates identified into nine kinds of staphylococcal enterotoxins virulence factor gene complex, the major molecular typing of enterotoxins virulence factor genome is sea-selk-selq-SCCmecIII-agrI (5 strains of 26%). Conclusion: Diverse molecular types with relatively high rate of multidrug resistance and elevated MIC to vancomycin were found in 19 MRSA isolates from patient with empyema. More information including demographic and laboratory data of patients with MRSA empyema are needed to correlate these data with molecular and phenotyping results and to identify molecular and phenotypic indicators for outcomes of empyema patients.