Amir Azimian - Department of Pathobiology and Laboratory Science, School of Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran.
Seyed Asghar Havaei - Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
kiarsh Ghazvini - Department of microbiology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
Mahsa Khosrojerdi - Department of Pediatrics, School of Medicine, Semnan University of Medical Sciences, Semnan, Iran.
Mahmood Naderi - Molecular Biology and Genetic Engineering Department, Stem Cell Technology Research Center, Tehran, Iran.
Siamak Samiee - Reference Health Laboratories, Ministry of Health and Medical Education, Tehran, Iran.

Introduction: Methicillin-Resistant Staphylococcus aureus (MRSA) is responsible for an increasing number of serious hospital- and community-acquired infections. USA۳۰۰ is known to be the most common cause of community-acquired infections, but recently there have been some reports on hospital-acquired infections caused by this strain. Methods: Totally ۱۷۱ isolates of S. aureus were collected from different clinical samples in selected university hospitals in Mashhad, Tehran, and Isfahan cities. Then, they were assessed by agar screening and disk diffusion methods to determine their resistance to Methicillin. The isolated MRSA strains were confirmed by detection of mecA gene. The staphylococcal cassette chromosome mec (SCCmec), agr, and spa typing and also detection of Panton-Valentine leukocidin (PVL) and arginine catabolic mobile element (ACME) genes were performed on mecA harboring isolates. Multilocus sequence typing was performed on PVL/ACME positive MRSA strains. Results: We found a PVL/ACME positive MRSA isolate. Genetic evaluation results for this isolate produced the following profile: positive for mecA, pvl, arcA, and hla genes, negative for vanA, sec, and tst۱, and belonged to agr I, SCCmec IV, sequence type ۸ (ST۸), and spa t۰۰۸. Conclusion: Our results suggest a finding of USA۳۰۰CA-MRSA isolate in Mashhad, Iran. This is an uncommon finding, because USA۳۰۰ is routinely found in areas other than Middle East. A notable point about these isolates is that they belong to American Endemic clones.

Staphylococcus aureus, Methicillin-Resistant, Panton-Valentine leukocidin, Iran.