Molecular characterization of Staphylococcus aureus strains isolated among hospital staff nasal carriers of Babol, Iran

Background: Staphylococcus aureus (s. aureus) nasal carriers, particularly the healthcare staff can be considered as a potential source for the spread of resistant strains. The aim of this study was to determine the molecular characterization of S. aureus strains isolated among the staff nasal carriers in one of the teaching hospitals in Babol. Methods: A total of 120 nasal swabs were taken from the staff of Ayatollah Rouhani Hospital Babol during 2016.  The antibiotic resistance pattern was performed by disc diffusion method for 13 antibiotics, including cefoxitin, cephalothin, teicoplanin, vancomycin, daptomycin, oxacillin, amoxicillin, amikacin, linezolid, ciprofloxacin, levofloxacin, erythromycin, rifampin, according to the CLSI 2015. Polymerase chain reaction (PCR) was used to detect mecA and pvl genes. Finally, the different SCCmec types were determined by multiplex- PCR method. Results: Among the 120 collected specimens, 40(33.3%) S. aureus isolates were approved. 28(70%) of strains were identified as methicillin-resistant Staphylococcus aureus (MRSA) and the frequency of pvl gene was confirmed 2(5%). Based on the multiplex PCR assay, four different SCCmec types were detected as 35.7% type I, 14.2% type III, 7.1% type II and 3.5% type IV. By a disc diffusion method, no resistance pattern was observed to vancomycin, while 100% of strains were resistant to amoxicillin. Conclusion: Consequently our results illustrated that isolated S. aureus strains among the staff nasal carriers via mentioned molecular characterization may lead to increase the nosocomial persistent infections in hospitalized patients and also health care workers.