Methicillin resistance in staphylococci isolated from dogs and their antibiotic susceptibility pattern

    In this study, the presence of methicillin-resistant gene (mecA) and antibiotic resistance pattern were investigated in coagulase positive staphylococci (Staphylococcus aureus and Staphylococcus pseudintermedius) isolated from referred dogs to Veterinary Hospital of Ahvaz. Nasal swabs were collected from 143 dogs referred to Veterinary Hospital of Ahvaz and were cultured in mannitol salt agar (MSA) and blood agar. Coagulase-positive staphylococci were identified by routine identification methods. From 67 coagulase-positive staphylococci (13 isolates Staphylococcus aureus and 54 isolates Staphylococcus pseudintermedius) and by using specific primers for the methicillin-resistant gene (mecA), 28 (41.79%) isolates possessed the mecA gene. The presence of this gene was showed in 7 Staphylococcus aureus (25%) and 21 Staphylococcus pseudintermedius (75%) isolates. Among isolates carrying methicillin resistance gene (mecA), maximum resistance was to ampicillin (92.85%) and then to penicillin (57.14%), cloxacillin (42.58%), oxacillin (35.71%), tetracycline (32.14%), ceftazidime (25%), erythromycin and azithromycin (21.42%), gentamicin and Ceftizoxime (14.28%), methicilline, norfloxacin, meropenem, and cotrimoxazole (10.71%). No resistance was observed to vancomycin, chloramphenicol, rifampin, and nitrofurantoin in these isolates. Among isolates without methicillin resistance gene (mecA), highest resistance was to ampicillin (84.61%) and then to penicillin (48.71%), tetracycline (23.07%), oxacillin (20.51%), gentamicin (7.69%), chloramphenicol, erythromycin, azithromycin, cotrimoxazole (5.12%) and ceftazidime (2.54%) respectively. No resistance was observed to oxacillin, meropenem, vancomycin, ceftizoxime, rifampin, methicilline and nitrofurantoin. Identification and monitoring of methicillin-resistant staphylococci and determination of their antibiotic susceptibility pattern are essential for successful treatment and preventing the spread of antibiotic-resistant strains. These studies have also led to awareness and promote effective practices to prevent the spread of resistant strains.