Molecular typing of Methicillin Resistance Staphylococcus aureus(MRSA) isolated from device related infections by SCCmec and PCR-RFLP of coagulase gene

Background: SCCmec and PCR-RFLP are productive and cost-effective methods for epidemiological investigations and source tracking of MRSA. Aim of this study was to investigate the epidemiology and molecular characterization of MRSA recovered from device related infection. Methods: A total of 626 MRSA were collected from prosthetic device related infections and subjected for presence of mec gene and SCCmec typing. SCCmec characterized MRSA were subjected for agr typing followed by RFLP genotyping and amplification of PVL gene. Following the Clinical & Laboratory Standards Institute (CLSI), antibiotic resistance pattern was determined. Results: Of 626 MRSA isolates, 488(78%) were characterized by SCCmec typing. Most common type was SCCmec IV (43%), followed by SCCmec II (25%) SCCmec III (22%) and only 10% was SCCmec V. SCCmec characterized MRSA strains were 100% resistance to tobramycin and chloramphenicol, 96% resistance to ciprofloxacin and 93% resistance to azithromycin. The genePVL was only present in SCCmec IV. All agr typed MRSA strains were resistance to gentamicin, tobramycin and chloramphenicol. PVL was present in all strains of agr III, 80% of agrIV, 50% of agrII and absent in agrI. RFLP analysis resulted in 16 types of non-duplicate unique bands pattern which were equally distributed among prosthetic device related infection. Conclusion: PVL harboring SCCmec or agr typed MRSA strains are less resistance to antibiotics. RFLP is simple, productive and cost-effective method for molecular typing of MRSA. Correct use of antibiotics and molecular surveillance is indispensable to detect the change in epidemiological and antibiotic resistance trends of MRSA