Bovine mastitis on selected farms in Kamwenge District: prevalence and antibiograms of the causative bacteria

Abstract

Bovine mastitis is an inflammation of the parenchyma of mammary glands characterized by physical, chemical, and usually bacteriological changes in milk, and pathological changes in glandular tissues of the udder. It is a costly infectious disease of cattle with worldwide occurrence presenting as either clinical or subclinical mastitis. A cross sectional study was conducted to determine the prevalence of bovine mastitis and antibiotic sensitivity profiles of selected mastitogenic bacteria to commonly available antibiotics on market in Kamwenge District. The study was conducted in two Sub counties; Bihanga and Nkoma and two Town councils; Kamwenge and Kahunge, in Kamwenge District. A total of 200 lactating cows were screened for mastitis using California Mastitis Test and physical examination. For cows testing positive for mastitis, we collected samples into sterile tubes for culturing to characterize the causative bacteria and carry out antibiotic sensitivity profiles using Kirby-Bauer disc diffusion technique. Later, a conventional Polymerase chain reaction (PCR) was carried out to screen for presence of MecA and TetM genes among the resistant Staphylococcus aureus isolates. The prevalence of bovine mastitis in the study area was 74.5% (149/200) of these, 95.3% (142/149) manifested as subclinical mastitis while clinical mastitis accounted for only 4.7% (7/149). Coagulase negative Staphylococci were most prevalent 47.8% (n=44) followed by coliforms 37% (n=34), Staphylococcus aureus (SA) 14.1% (n=13) and Corynebacterium sp. 1.09% (n=1). There was a high level of resistance by Coagulase negative staphylococci to Penicillin 81.8% (n=63) and Tetracycline 59.7% (n=46) but showed marked susceptibility to Gentamicin 74% (n=57) and Cefoxitin 58.4%, (n=45). PCR results for Staphylococcus aureus isolates indicated presence of the MecA gene in three isolates while all were negative for the TetM gene. In the multivariate logistic regression analysis, factors significantly associated (p< 0.05) with occurrence of mastitis included herd size, kraal hygiene and milking order. This study indicated that the burden of mastitis and resistance to common antibiotics (penicillin and tetracycline) are a reality among the visited dairy farms in Kamwenge District. This calls for continuous sensitization of farmers about best practices to prevent and control this production related condition.