Evaluation of humoral immunological response of newly prepared bovine multidrug-resistant Staphylococcus aureus mastitis vaccines in rabbits.

Abstract

Multi-drugs resistant (MDR) Staphylococcus aureus is creating challenges to cure cow mastitis, resulting in massive economic loss globally. It necessitates the adoption of prevention and control systems such as vaccination. Plain (PMRSAV), Montanide oil adjuvanted (MMRSAV) and Aluminum hydroxide adjuvanted (AMRSAV) vaccines were prepared using a molecularly characterized isolate of MDR S. aureus from bovine origin. Immunogenicity of the selected isolate was evaluated in five groups of rabbits (A-E) at different concentrations by measuring GMT via IHA from serum samples after booster shot. The group E provoked significantly higher (P<0.05) antibody titer with peak at day 28 (64&#xb1;0.5) and cumulative mean antibody titer (CMT) of rabbits was highest (45.6) followed by groups C (35.9), D (32.7), B (30.3) and A (24.5). The concentration yielding maximum antibody titer was used for vaccines preparation. Vaccines were evaluated in different rabbits groups by inoculating PMRSAV, MMRSAV, AMRSAV and Placebo. Serum samples evaluated through IHA revealed that rabbits injected with MMRSAV produced highest antibody titer reaching its peak at day 45 (90.51&#xb1;0.23) with a slight decrease until day 60 (80.63&#xb1;0.17) followed by AMRSAV and PMRSAV. Challenge protection assay revealed the survival rates of rabbits in groups PMRSAV, MMRSAV, AMRSAV and Placebo as 83.3%, 100%, 100% and 16.7%, respectively. The study concluded that MMSAV and AMSAV were safe, efficacious and immunogenic in experimental rabbits.