Background: The emergence of antibiotic resistance, particularly resistance to methicillin in Staphylococcus aureus has made the treatment process more difficult. Therefore, producing of an effective vaccine seems to be necessary to prevent infections with methicillin-resistant Staphylococcus aureus (MRSA). In this study, a mixture of naloxone and alum has been used to improve the efficacy of a vaccine against MRSA.

Materials and Methods: MRSA 834 strain was grown on TSB medium and the grown cells were harvested and killed by sonication and were used as a vaccine model. Balb/c mice were divided into six groups and the vaccines were either injected alone, with naloxone, alum, or a mixture of naloxone - alum and control group received naloxone and PBS buffer. Total IgG antibody level was measured by ELISA method and finally, the challenge test of this bacterium was performed and the mice were examined regarding the degree of bacteria growth in their kidneys.

Results: The serum level of Total IgG antibody in the mixture of naloxone – alum with MRSA group was shown to be significantly increased (p<0.05). Furthermore, the lowest bacterial load was observed in this group.

Conclusion: It seems that a mixture of naloxone and alum as an adjuvant with the killed methicillin-resistant Staphylococcus aureus enhances the humoral immunity leading to a high level of protection against MRSA infections. Therefore, this seems to be a good option for improving the performance of this vaccine.

Background: Pathogenic Pseudomonas aeruginosa strains produce a polar flagellum that required for motility, adhesion, invasion and secretion of virulence factors. The aim of this study was to evaluate the effect of prevention and treatment with anti-recombinant type B flagellin antibody in a burned mouse model.

Materials and Methods: One hundred twenty six mice were divided into 16 groups injected with different regimen of anti-recombinant type B flagellin antibody. Infections were caused by sub-dermal injection of P. aeruginosa PAO1 and PAK strains at the burn site. Groups were monitored for mortality for one week. Additionally, functional activity of this antibody was assessed by motility inhibition and opsonophagocytosis assays.

Results:  Immunotherapy with rabbit antisera substantially increased (85.71%) survival rate of mice challenged with a homologous strain PAO1 compared with the control PBS. The mortality rate in mice infected by the heterologous strain PAK was only 28.57%. This antibody increased phagocytosis killing of the homologous strain but it only had a slight effect on the heterologous strain.

Conclusion:  Passive immunotherapy protected burned mice challenged with the homologous strain but showed lower efficacy against the heterologous strain.