Molecular and Bacteriological Study of Vancomycin Resistant Staphylococcus Aureus (VRSA) Isolated from Buffalo Raw Milk in Baghdad

One hundred buffalo raw milk samples from different locations in Baghdad governorate, Iraq, were tested for Vancomycin-resistant Staphylococcus aureus (VRSA) by streaking on a plate of mannitol salt agar plate and incubated in 37  for 24hr then inoculated on blood agar. The isolates were confirmed according to colony morphology, Gram staining and conventional biochemical techniques and polymerase chain reaction (PCR) to detect vanB gene. The disc diffusion testing was done to determine antimicrobial resistance including VRSA. Staphylococcus aureus (S. aureus) was found in 46 (46%) of raw buffalo milk. The isolates exhibited high resistance (80%) to methicilin, 75% to Oxacillin and Cefoxitin, 55% to gentamycin, and 50% to vancomycin. The phenotypic analyses revealed that out of 46 S. aureus, 23 (50%) were VRSA. While the genotypic identification by PCR showed that out of the 23 VRSA, 18 (78.2%) isolates had vanB genes. Results highlight the potential zoonotic risk of buffalo milk as a potential source of VRSA, which may be transmitted to human beings working in close contact with the buffalos.