Antibacterial activities of bioactive compounds extracted from Marine algae Gracilaria salicornia against Aeromonas hydrophila

Herbal medicinal products have attracted significant research interest in recent years. Considering the efficiency of algae products in controlling pathogenic bacteria and also easy access to large resources of algae, this study was conducted to evaluate the effects of methanolic, chloroformic and aqueous extracts of Gracilaria salicornia against Aeromonas hydrophila, a heterotrophic, Gram-negative, rod-shaped bacterium found mainly in warm climate. Algae samples were collected from Qeshm Island coastlines and transferred to the laboratory. Standard methods were used to obtain the algae extract. Antibacterial activities of various extracts were tested against the bacterium using well diffusion assay method. Significant differences were observed in antibacterial activities of different extracts (P<0.05). The diameter of zone of growth inhibition varied in correlation with concentration of the extracts (50, 100, 200 and 300 mg.ml-1). The best inhibition zone was observed at 100, 200 and 300 mg.ml-1 methanolic and 300 mg.ml-1 aqueous extracts

Immunoprotectivity of Salmonella enterica serovar Enteritidis virulence protein, InvH, against Salmonella typhi

Objective(s):Typhoid fever is a dreadful disease of a major threat to public health in developing countries. Vaccination with bacterial immunodominant components such as surface proteins may prove as a potent alternative to live attenuated vaccines. InvH, an important part of needle complex in type three secretion system (TTSS) plays important role in efficient bacterial adherence and entry into epithelial cells. Materials and Methods:In this work we used a 15 kDa recombinant InvH protein of Salmonella enteric serovar Enteritidis to provoke antibody production in mouse. The mice were immunized by recombinant InvH and challenged with Salmonella typhi. Histopathology of spleen and liver were studied. Results:The immunized mice showed a significant rise of antibody after the second booster. The immunization induced protection against high doses of S. typhi. The bacterial challenge with sera showed significant protection against challenge dose of 2×109 CFU. Immunized sera reacted with          S. typhi markedly. Immunoreaction of bacterially infected sera and InvH protein was significantly higher than the control group. Bacterial loads of S. typhi in spleen was more than liver. Decreased bacterial load was evident in immunized mice after 7 days. Histological examination of the liver showed the immunized mice liver remained unaffected. Conclusion: Efficacy of the virulence protein, InvH, in inhibition of this phenomenon by active immunization was shown here. It may be concluded that InvH, as an antigen, can develop protection against S. typhi infections. InvH may be exploited in protective measures as well as a diagnostic tool in Salmonella infections

Ceasing down Pseudomonas aeruginosa Invasiveness in A Mouse Burn Wound Sepsis Model by Recombinant OprF

Background: Bacterial infections in burn and wound patients are common and difficult to control. The aim of the current study was to evaluate the ability of full length OprF to elicit the production of protective IgG in mice burn wound sepsis model against P. aeruginosa infection. Methods: OprF protein was expressed and purified by Ni-NTA. The purified protein as used to immunize BALB/c mice. The antibody raised against OprF was confirmed by ELISA and evaluated by immunoblot analysis. After burn and bacterial challenge, mortality rate was monitored in the control and immunized mice groups. Bacterial quantity in skin, blood, spleen and liver was evaluated to study spread or inhibition of the infection. Results: Immunization of mice with OprF brought about a significant rise in anti-OprF sera titer. Protection was imparted in the immunized group resulting in 100% survival against 1000 fold LD50 challenge with P. aeruginosa. The antiserum against OprF was able to significantly inhibit the systemic spread of P. aeruginosa infection from the infection site to internal organs. Conclusions: The results suggest that anti-P. aeruginosa OprF antibodies elicited in burn wound sepsis model by active immunization are protective against infection with P. aeruginosa, and provide a rational for further development of the vaccine for prevention against P. aeruginosa infection in burn patients