Molecular profiling of methicillin‑resistant Staphylococcus aureus isolated from healthy pet dogs and their owners in western Iran

Background and Objectives: Growing apprehension surrounds methicillin-resistant Staphylococcus aureus (MRSA) strains. The objective of this investigation was to molecularly profile MRSA strains recovered from asymptomatic com- panion dogs and their human caretakers in Kermanshah, located in western Iran, marking the inaugural research of its kind within the country. Materials and Methods: During a six-month period, specimens were obtained from the oral cavities and nasal passages of 200 clinically normal pet dogs, as well as their owners. MRSA isolates were identified, DNA was extracted, and character- ized via staphylococcal cassette chromosome mec (SCCmec), accessory gene regulator (agr), and staphylococcal protein A (spa) typing, plus detection of mecA and Panton-Valentine leukocidin (PVL) genes. Results: Eighteen MRSA isolates were identified (12 from dogs, six from owners). All carried mecA. Most had SCCmec type III. Human isolates included one agr II and two agr IV; no dog isolates were agr-positive. Isolates belonged to four spa types: t690 (dogs) and t325, t037, t030 (owners). PVL genes were absent. Isolates from dogs and owners showed type diversity. Conclusion: This study reveals MRSA epidemiology in healthy dogs and owners in Iran, with low colonization rates. Con- tinuous monitoring is essential to track MRSA circulation, as colonization raises infection risk.