Prevalence of Hemolysins in methicillin resistant Staphylococcus aureus isolates of healthy community

Introduction and Objectives: Methicillin resistant Staphylococcus aureus (MRSA) is the main cause of infections ranging from minor skin infections to serious infections in hospitals and community settings. Alpha hemolysin (hla) and beta hemolysin(hlb) are the most common survival factors in S. aureus. The current study is aimed to detect hla and hlb genes in nasal methicillin resistant S. aureus isolates in the student population. Materials and Methods: A total of 400 samples were obtained from the nasal of students schools in areas 1 and 3 at Tabriz city. After confirmation of S. aureus strains by standard biochemical tests, the antibiotic resistance pattern was determined by disk diffusion method. Phenotypic test of MRSA strain was performed using oxacillin 30 μg /disc, and methicillin sensitivity test was performed by cefoxitin 30 μg/disc. The presence of mecA, hla and hlb genes was examined by PCR reaction. Results: Of 400 samples, 15% (60 cases) were positive S. aureus. Among them, 18.34% (11 samples) were MRSA based on disk diffusion. The highest antibiotic resistance was observed to ampicillin (100%) and the highest sensitivity was against vancomycin (100%). Based on PCR results, 60% cases were positive mecA. These results were indicating the emergence of Oxacillin susceptible mecA positive strains (OS-MRSA) for the first time in health community in IRAN.In this study, 88.33% of cases were positive for hla gene and 63.36% were positive for hlb gene. Conclusion: The prevalence of carriage of hla/hlb positive S. aureus indicates an essential need for monitoring of nasal carriers in healthy community to prevent subsequent infections.

کلیدواژه ها:

Staphylococcus areus ، MRSA ، MEC-A ، hla ، hlb.