A First Case Report of Mannheimia haemolytica in Caprine Mastitis in Theni District of Tamil Nadu, India

Aim: To identify and assess the etiological agent responsible for caprine mastitis in a doe, analyse the antibiotic sensitivity and provide suitable treatment. Study Design: Clinical examination and microbiological analysis, followed by antibiotic sensitivity testing. Place and Duration of Study: Veterinary College and Research Institute, Theni. Case presented in the month of November, 2023. Methodology: A 31 kg doe with a history of udder swelling and watery milk from the right quarter was examined. Clinical examination revealed a swollen, painful and indurated udder. The California Mastitis Test confirmed the mastitis, and the milk sample was collected aseptically for microbiological analysis. After initial inoculation in nutrient broth and after overnight incubation, the culture was streaked onto MacConkey agar. Bacterial identification was done by routine biochemical tests). Antibiotic sensitivity testing (ABST) was conducted using the Kirby-Bauer disc diffusion method. Results: Gram staining revealed Gram-negative coccobacilli with bipolar staining resembling Mannheimia hemolytica. The tiny red pinpoint colonies on MacConkey agar and positive catalase, oxidase, and indole tests were suggestive of Mannheimia hemolytica. ABST showed resistance to Penicillin, Ampicillin, Methicillin, and Metronidazole, while sensitivity was observed to Amoxicillin Clavulanic acid, Ciprofloxacin, Gentamicin, Cefixime, Ceftriaxone, Enrofloxacin, Chloramphenicol, Streptomycin, Tetracycline, Oxytetracycline, Trimethoprim, and Sulfonamide. Treatment with Ceftriaxone (10 mg/kg) intra-venously and Meloxicam (0.5 mg/kg) intramuscularly, along with topical Mastilep for three days, alleviated udder pain and hardness. Conclusion: Mastitis in goats is commonly caused by Staphylococcus spp.; however, Mannheimia hemolytica is a rare but possible etiological agent. This case represents the first report of Mannheimia hemolytica-induced mastitis in Tamil Nadu, indicating a need for further molecular study of this pathogen in caprine mastitis. Mannheimia hemolytica can impinge on the wellness of goats; therefore timely diagnosis and therapeutic interventions are highly essential to maintain the economic status of goat farms.