Prevalence and antibiotics resistance of Staphylococcus aureus isolates isolated from raw milk obtained from small-scale dairy farms in Penang,Malaysia

The study was carried out to determine the prevalence and antibiotics resistance of s. aureus in raw milk samples obtained from dairy farms in penang,malaysia. a total of 60 samples were examined and all the samples examined were positive for s. aureus with counts ranging from 2.88 to 3.41 log cfu/ml. milk samples obtained from different farms had similar s. aureus counts (p>0.05). all the isolates examined were susceptible to gentamycin,kanamycin,chloramphenicol and ciprofloxacin. s. aureus isolates were resistant to penicillin (23.3%),ampicillin (23.3%),trimethoprim (18.3%),cefoxitin (15.0%),linezolid (11.7%),clindamycin (10.0%),erythromycin (8.3%) and tetracycline (5.0%). 28.3% of the isolates were resistant to at least one antibiotic with mar index ranging from 0.08 to 0.67. the following genes,blaz,erma and tetk were detected in 9,5 and 1 isolate/s of s. aureus respectively. presence of high s. aureus counts and antibiotic resistant strains of s. aureus might pose a health hazard if milk is not pasteurized adequately and prolonged storage of milk after milking at ambient temperature might further aggravate the problem. © 2016 pvj.