METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS IN MASTITIC MILK

Hend Mohamed, Dalia Talat, Abd El Gawad Kadoom and Madiha Salah Ibrahim*

ABSTRACT

Methicillin-resistant Staphylococcus aureus (MRSA) is one of most contagious bacterial infections resistant to numerous antimicrobials including methicillin, oxacillin, amoxicillin and penicillin. This study was performed to evaluate the occurrence of MRSA in cow milk samples and to investigate the antimicrobial resistance and molecular characteristics of these strains as well as virulence genes using PCR. A total of 114 samples of subclinical mastitic cow milk were collected from different dairy farms in Kafr El Sheikh governorate, Egypt. S. aureus was isolated from 24 milk samples (21%). The results of antibiogram testing revealed that S. aureus isolates were highly resistant to methicillin, penicillin, clindamycin and ampicillin (100%), followed by tetracycline (83.3%), amoxicillin-clavulanic acid (58%), neomycin and streptomycin (46%) gentamycin (25%). On the other hand, the isolates were highly sensitive to ciprofloxacin. PCR amplification of methicillin- resistance gene, mecA, revealed that 100% of the examined isolates were positive. While, staphylococcal enterotoxin A sea gene was detected in 8% of the isolates. This may indicate that multiple drug resistance S. aureus strains.

Keywords: Staphylococcus aureus, Antibiotic sensitivity, mecA, Staphylococcal enterotoxin.