Reza Besharati, Ali Haghbin, Seyed Ahmad Hashemi, Ahmad Vosoughi-Motlagh, Amir Azimian
Staphylococcus pseudintermedius , a commensal in dogs, is an emerging zoonotic pathogen with increasing methicillin-resistant (MRSP) strains. This study investigated MRSP isolates from hospital environments and healthcare workers in Bojnurd, Iran, to assess antimicrobial resistance and zoonotic potential. Nasal swabs from healthcare workers ( n = 40) and hospital supplies ( n = 35) were cultured. Phenotypic and genotypic analyses included antimicrobial susceptibility testing (Kirby-Bauer), PCR for resistance ( mecA , vanA , cfr ) and virulence genes ( pvl , hla , icaA/D ), SCC mec typing, and multilocus sequence typing (MLST). Two MRSP isolates (ST2361) were identified, one from a nasal swab and another from hospital supplies. Both exhibited resistance to β-lactams (cefoxitin, penicillin), fluoroquinolones, macrolides, and sulfonamide-trimethoprim, but susceptibility to tetracyclines, gentamicin, linezolid, and vancomycin. PCR confirmed mecA and virulence genes ( pvl , hla , icaA/D ). A SCC mec pattern consistent with type IV and identical ST2361 profiles suggested potential clonal relatedness. The presence of MRSP ST2361 in humans and hospital environments highlights its zoonotic and nosocomial transmission risks. The isolates' multidrug resistance and virulence genes underscore the need for improved diagnostics, antimicrobial stewardship, and infection control measures in healthcare settings.