02 Dec 2022
30 Nov 2022
The study aimed for isolation and molecular investigation of Staphylococcus aureus (S. aureus) isolated from clinical mastitis in ewes. 119 ewes located in Al-Rasheed, Al-Yousifya, and Al-Latifya in Baghdad city, were examined for systemic reaction and local examination of the udder. 238 ewes’ milk samples were collected at aseptic conditions for bacterial isolation, antimicrobial susceptibility test and molecular assay by polymerase chain reaction (PCR) for 23srRNA and acc-aph genes and phylogenetic analysis. Bacteriological isolation was done by culturing on Blood agar, Mannitol salt agar, Staph-110 agar, and selective Hi Chrome agar. The isolates were examined by Gram stain and different biochemical tests. From a total of 119 ewes and 238 teat halves examined, 10.08% and 7.31% were affected with clinical mastitis, respectively. Ten out of 238 (4.20%) samples were positive to S. aureus. The isolates were susceptible at 100% to Ciprofloxacin, Tetracycline and Neomycin, 80% to Amikacin, 50% Oxacillin, and highly resistance to Methicillin, Erythromycin and Penicillin at 100%, 80% and 70%, respectively. PCR assay revealed that all 10 S. aureus carried 23rRNA and only two isolates (resist to amikacin) possess acc-aph gene. Sequencing of the 2 isolates positive to acc-aph contains a mutation and the evolutionary tree was drawn using MEGA and NCBI for analysis and compare of aac-aph gene, it appeared when compared with the world that two samples isolate from Iraqi have different from world as 99%.