Prevalence and antimicrobial resistance of coagulase-positive staphylococci isolated from raw goat milk

• Goat milk was examined for the presence and number of staphylococci.
• Antimicrobial resistance of the isolates, including resistance to methicillin, was determined.
• Several Staphylococcus isolates were resistant to penicillin and sulphamethoxazole.
• The results indicate that raw goat milk may cause a risk for consumers.

Consumption of goat milk products has been increasing during recent years due to goat milk's health benefits and their pure nutritional value. Staphylococcus bacteria, especially Staphylococcus aureus, are one of the main etiological agents involved in milk contamination and foodborne human infections. In the present study the prevalence of coagulase-positive staphylococci (CPS) in raw goat milk and the antimicrobial resistance, especially to methicillin, of these bacteria were evaluated. CPS were detected in 86.1% samples at the level of 1.0 × 100 to 4.0 × 104 colony forming units per milliliter (CFU/mL). CPS were isolated to the total of 207. Antimicrobial resistance showed that 15.5% of them were resistant to penicillin, 12.1% to sulphamethoxazole, and 6.3% to tetracycline and cefoxitin. Nineteen isolates (9.2%) were resistant to other antimicrobials (erythromycinum, streptomycin, gentamicin, chloramphenicol, florfenicol, and trimethoprim). All tested isolates were susceptible to ciprofloxacin. Nearly two-thirds of the strains, (136, 65.7%) were susceptible to all 11 antimicrobial agents used in the study. Methicillin-resistant S. aureus (MRSA) strains were not identified in the tested samples. The results of the study showed that antimicrobial-resistant S. aureus had been found in goat milk.