Bovine mastitis: The causative agents and the antimicrobial susceptibility

Abstract

Abstract The study was conducted to investigate the occurrence of bovine mastitis in HilatKuku,Khartoum, to isolate the bacteria responsible for causing the disease and to determine the antimicrobial susceptibility to the related bacteria. Fifty samples of mastitis milk from fifty dairy cows were collected and transported to Microbiology Laboratory of The College of Veterinary Medicine – Sudan University of Science Technology. Isolation and identification of the bacteria from the collected mastitic milk was undertaken. The results revealed high prevalence of Staphylococcus aureus 48% followed by Streptococcus agalactiae 28%, Proteus spp. 12%, Starphylococcus hyicus 8% and Streptococcus dysgalactiae 4%. Three types of inflammation were detected, acute mastitis with high prevalence (66%) followed by chronic mastitis (32%) and gangrenous mastitis (2%). Staphylococcus aureus was found to infect one quarter causing chronic mastitis and sometimes acute mastitis. Starphylococcus hyicus was found to infect one quarter causing chronic and acute mastitis. Streptococcus agalactiae was found to infect one quarter causing acute and chronic mastitis. Streptococcus dysgalactiae was found to infect more than two quarters causing acute mastitis. While Proteus spp. involved the four quarters causing mainly acute mastitis. The effective antibiotics used during this study against most of the isolated bacteria were Gentamycin, Amikacin, Chloramphincol, Oflaxacin and Ciprofloxacin. Some isolates showed resistant to some antibiotics which were Penicillin, Ampicillin, Cefotaxime, Cloxacillin and Gatifloxacin. Histopathological changes of the examined parenchymal tissue showed parenchymal damage and formation of abscesses. Seven samples from the ten examined parenchymal tissues samples showed necrosis of the mammary gland. These were mostly caused by Staphylococcus aureus causing chronic mastitis. Two samples showed hemorrhagic interstitial tissue mainly caused by E. coli and Streptococcus spp. causing acute mastitis. Only one sample showed necrotic alveoli in the .parenchymal tissue due to gangrenous type of inflammation