Distribution and antibiotic susceptibility profiles of Staphylococcus spp isolated from unpasteurized cow milk locally consumed in Nkonkobe local municipality, South Africa

Background Mastitis in cattle has been associated with infectious agents and trauma to secretory cells. Reduction in the quality and quantity of milk from dairy animals with concomitant adverse economic effects has been the leading implication of bovine mastitis. The leading microbes implicated in mastitis include Staphylococcus spp and coliforms among others. Consequently, this study aimed at the determination of the prevalence and in vitro susceptibility profiles of Staphylococcus spp in milk produced from dairy farms in the Nkonkobe region, Eastern Cape Province, South Africa. Methods A total of 384 milk samples were collected from three farms. Identification was performed based on conventional biochemical techniques employing the API Staph test kits whilst antibiotic susceptibility was determined by the disc diffusion assay. Results A total of 190 Staphylococcus spp were isolated in the study. Staphilococcus aureus (33.7%) was the most prevalent followed by S. xylosus (17.3%), while S hyicus (1.6%) and S saprophyticus (1.6%) were least isolated. Almost all isolates of S aureus 63 (98.4%) were resistant to penicillin G. How- ever, 97% of the isolates were susceptible to chloramphenicol and streptomycin, while susceptibilities of 93.7% to both vancomycin and neomycin were observed. All the other species of Staphylococcus were generally susceptible to most of the antibiotics studied. Percentage susceptibility of 100% was demonstrated against vancomycin, amoxicillin, streptomycin, neomycin, and rifampin respectively. Multidrug resistance was a commonly observed phenomenon in the study with S aureus showing 98% prevalence. Conclusions These results indicate that Staphylococcus spp are prevalent in raw milk in the Nkonkobe region of the Eastern Cape Province, with isolates being resistant to several antibiotics which are used in the prevention and treatment of mastitis. These findings are of veterinary and clinical significance and therefore call for attention to address the situation.