Antibacterial Activity of Isolated Immunodominant Proteins of Naja Naja (Oxiana) Venom

The aim of this study is to investigate antibacterial effects of immunodominant proteins isolated from the venom of Naja Naja Oxiana snake against Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa. The innate immune system is an important line of defense against bacterial diseases. Antibacterial peptides and proteins produced by snake venoms have recently attracted significant attention due to their relevance to bacterial diseases and the potential of being converted into new therapeutic agents. Identification of immunodominant proteins of the venom of Naja Naja Oxiana snake was performed by SDS-PAGE and western blot analysis. Identified proteins were isolated directly from preparative gel electrophoresis by Electro-elution. In the next step, antibacterial effects of immunodominant proteins were tested against several strains of clinical isolates, including S.aureus, B.subtilis (Gram-positive bacteria) P.aeruginosa and E.coli (Gram-negative bacteria) using broth microdilution and disc-diffusion assays. In order to compare the results of the disc-diffusion assay, antibacterial effects of several antibiotics (Gentamicin, Ampicillin, Penicillin, Amoxicillin and Ciprofloxacin) were also examined using the same conditions. Results showed that immunodominant proteins of (14, and 65kDa) with high immunogenicity were very effective in inhibiting the growth of two Gram-positive bacteria (S.aureus, B.sub) that were tested. However, they were only moderately effective in inhibiting the growth of the two tested Gram-negative bacteria (P.aeruginosa and E.coli). However, immunodominant proteins of 22 kDa and 32kDa with high immunogenicity, showed slight effectiveness in inhibiting the growth of two; the Gram-positive and Gram-negative bacteria that were tested. To the best of our knowledge, these immunodominant proteins are novel antigens for potent antimicrobial effects against two gram-positive bacteria (S.aureus, B.subtilis ) and less antimicrobial effect against two gram-negative bacteria (E.coli, P.aeruginosa) that were prepared .