Abstract

Quarter milk samples from cows were examined to determine the prevalence ofStaphylococcus aureus (SA) and different antibiotic resistant pattern were determined in a cross-sectional study design. The aim of this study was to isolate Staphylococcus aureusfrom samples of cow’s milk obtained from Hawassa area and to determine their antibiotic susceptibility patterns. A total of 160 milk (CCP1 to CCP5) samples were collected and screened for the presence of S. aureus. Gram staining, oxidase, catalase, DNase, haemolysis and coagulase tests were employed for bacterial identification. All the samples were contaminated with S. aureus. A total of 78 S. aureus isolates were obtained during this study. The levels of contamination with S. aureus were higher in milk obtained from CCP1, CCP2, CCP3, CCP4 and CCP5 at Hawassa area farms (18.0, 25.6, 27.0, 21.8 and 7.7%) respectively. A large percentage of the S. aureus isolates (25.6 and 27.0%) were from CCP2 and CCP3. All strains were resistant to penicillin G (PG), ampicillin (AP), amoxicillin-clavulanic acid (AC), ciprofloxacin (CIP), erythromycin (E), Ceftriaxone (CRO), trimethoprime-salfamethoxazole (TMP-SMZ) oxacilin (Ox) and vancomycin (V), 67.9, 70.9, 30.9, 0, 32.1, 23.1, 7.7, 60.3 and 38.5% respectively. The proportion of isolates resistant to CIP, TMP-SMZ, CRO, AC, E and V were low compared to AP, PG and Ox. S. aureus is normally resident in humans; therefore, the S. aureuspresent in the cow’s milk may have resulted from transmission between the two species, emphasizing the need to improve sanitary conditions in the milking environment.

Key words: Penicillin G (PG), ampicillin (AP), amoxicillin-clavulanic acid (AC), ciprofloxacin (CIP), erythromycin (E), ceftriaxone (CRO), trimethoprime-salfamethoxazole (TMP-SMZ), oxacilin (Ox), vancomycin (V).