Molecular Epidemiology of Panton-Valentine Leukocidin Harboring Hospital-Associated Methicillin-Resistant Staphylococcus aureus in Septicemic Children, Northeastern Iran, Bojnurd

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for an increasing number of serious hospital- and community-acquired infections in adults and children. Sepsis caused by S. aureus is one of the major health problems associated with treatment failure in adults; however, its clinical outcomes, the rate of treatment failure, and its molecular epidemiology are poorly understood. Objectives: The objective of this study was to evaluate the molecular epidemiology of Panton-Valentine Leukocidin (PVL) harboring MRSA strains isolated from children's blood culture in Bojnurd. Methods: Totally, 58 S. aureus strains were isolated from blood cultures in the major teaching hospital in Bojnurd. After the primary verification of Methicillin resistance by agar screening method, the isolated MRSA strains were confirmed with the detection of the mecA gene. MecA-positive strains evaluated for SCCmec, agr, and toxin profiles. Panton-valentine leucocidin-positive isolates were subjected to be evaluated for spa and sequence type (ST). Results: Our data indicated 53.4% (31) of isolates were MRSA. Twelve (38.7%) of these isolates had PVL gene that 25% (3) of them had tsst-1 gene and 58.3% (7) had etb gene. One (3.2%), 64.5% (20), and 32.2% (10) of these isolates belonged to SCCmec I, III, and IV, respectively. Predominant ST and spa types among PVL positive isolates were ST6 and t304, respectively. Conclusions: We had an uncommon finding because PVL was routinely found in community-acquired MRSA, but in this study we found PVL harboring hospital-associated MRSAs. A notable point about these isolates is that most of them belonged to Asian endemic clones.