P. multocida in India Isolation, Resistance, and Co Infection Dynamics: Epidemiology, Resistance Profiles Patterns of Pasteurella Across Indian Regions Livestock

Pasteurella multocida is a significant pathogen causing fowl cholera in poultry and infections in multiple hosts. This cross-sectional study evaluated its prevalence, genotypes, antibiotic resistance, and pathogenicity in commercial poultry across nine Indian states. A total of 191 bone samples from suspected cases were cultured and confirmed by biochemical tests and PCR. Forty-eight isolates were identified and genotyped. Antibiotic sensitivity testing (Kirby-Bauer method) showed 100% susceptibility to enrofloxacin, co-trimoxazole, and chloramphenicol, while ampicillin, amoxycillin, and gentamicin showed 87.5% susceptibility. Pathogenicity testing in SPF chickens reproduced typical fowl cholera lesions, and the organism was re-isolated from infected birds. Genotyping revealed LPS genotype-1 (34), genotype-3 (6), genotype-4 (1), and genotype-5 (7). The study also detected co-infections with ALV, MG, and CAV using PCR. Co-infections increased disease severity, respiratory distress, immunosuppression, and mortality. Findings highlight emerging multidrug resistance and emphasize biosecurity, vaccination, and early diagnosis for effective control in Indian poultry systems.