Isolation, characterization, virulence and immunogenicity testing of field isolates of Pasteurella multocida, Staphylococcus aureus, and Streptococcus agalactiae in laboratory settings

The present study was designed to investigate isolation, characterization, virulence and immunogenicity testing of field isolates of Pasteurella multocida, Staphylococcus aureus, and Streptococcus agalactiae in rabbits and mice. Isolates of P. multocida, S. aureus and Str. agalactiae recovered from field cases of Hemorragic septicemia and mastitis were scrutinized for virulence/pathogenicity and immunogenicity. Mouse LD50 of P. multocida showed that P. multocida isolate No.1 was more virulent than isolates No. 2 and 3. Virulence of isolate No.1 S. aureus and Str. agalactiae revealed that 100, 80% rabbits died within 18 h of inoculation. Seven-digit numerical profiles of these 4 isolates with API (R) Staph test strips isolates, No.1 (6736153) showed good identification (S. aureus id = 90.3%). Indirect ELISA-based serum antibody titers to P. multocida isolate No.1, S. aureus No.1, Str. agalactiae, isolate No.1 elicited high antibody titers 1.9, 1.23, 1.12 respectively. Conclusion: All the pathogens of Isolate No. 1 (P. multocida, S. aureus Str. agalactiae), were high antibody than others isolates.