Staphylococcal Cassette Chromosome Mec Types And Expression Of Panton-Valentine Leucocidin In Methicillin-Resistant Staphy Lococcus Aureus

Objective: To study resistance of MRSA to antibiotics and its distribution, and detect mecA, Panton-Valentine leucocidin (PVL) and SCCmec typing of MRSA isolates. Compare the differences of PVL and SCCmec between the CA-MRSA and HA-MRSA. Get the message of the molecular epidemiologic characters of MRSA in our hospital and guide the treatment and prevention of MRSA infections.Methods: The minimal inhibitory concentrations (MIC) of 8 kinds of antimicrolbiac agents against 65 strains of MRSA were tested by serial two-fold agar dilution method. Their DNAs were extracted by alkali splitting method. Detect mecA and PVL by polymerase chain reaction (PCR). SCCmec typing(â… -â…¤) of all clinical isolates of MRSA was performed by novel multiplex PCR assay.Results: The 65 strains of MRSA mainly distributed in ICU (15.1%), neurosurgery department (15.1%), respiratory department(12.1%), neurology department (12.1%), dermatology department (12.1%) and infection disease ward (9.1%) .Most of them came from sputum, secretion, The resistant rate to rifampicin, moxfloxacin, cefathiamidine, SMZ, clindamycin and amikacin were 89.2%,92.3%,83.1, 96.9%,86.1% and 55.3% respectively. 100% MRSA strains were susceptible to glycopeptides such as vancomycin. The resistant rate of CA-MRSA was lower than that of HA-MRSA. PVL had been found in 11 strains of these MRSA, 3 of them came from secretion, 1 strain came from ascite while 7 strains came from sputum. There were 4 CA-MRSA strains and 7 HA-MRSA strains. All of the isolates genotypied into SCCmec typeâ…¢. Conclusions: This study has demonstrated that MRSA isolates in our hospital are resistant to multidrug, but sensitive to glycopeptides, therefore glycopeptides is recommended as the first line candidate medicine to treat the MRSA infections, amkacin can be used as auxiliary medicine. The positive rate of PVL in CA-MRSA is higher than in HA-MRSA. The SCCmec type of MRSA in our hospital is unity. Maybe these "CA-MRSA" isolates are indeed "HA-MRSA", or there have some difference at special gene site between them.