Assessment of the Antimicrobial Activity of Few Saudi Arabian Snake Venoms

BACKGROUND: Venoms of two cobras, four vipers, a standard antibiotic and an antimycotic, were evaluated comparatively, as antimicrobials. METHODS: Six venom concentrations and three of the standard antibiotic and the antimycotic were run in micro-dilution and diffusion plates against the microorganisms. RESULTS: Echis pyramidum, Echis coloratus and Cerastes cerastes gasperettii highest venom concentrations gave significant growth inhibition zones (GIZ) with respect to a negative control, except Bitis arietans, whose concentrations were significant. The cobra Walterinnesia aegyptia had significant venom concentrations more than Naja haje arabica. The Staphylococcus aureus Methicillin Resistant (MRSA) bacterium was the most susceptible, with a highly (P < 0.001) significant GIZ mean difference followed by the Gram positive Staphylococcus aureus, (P < 0.001), Escherichia coli (P < 0.001), Enterococcus faecalis (P < 0.001) and Pseudomonas aeruginosa which, had the least significance (P < 0.05). The fungus Candida albicans was resistant to both viper and cobra venoms (P > 0.05). The antibiotic Vancomycin was more effective than snake venoms though, they were more efficient in inhibiting growth of the resistant Pseudomonas aeruginosa. This antibiotic was also inactive against the fungus, whilst its specific antifungal Fungizone was highly efficient with no antibacterial activity. CONCLUSIONS: These findings showed that snake venoms had antibacterial activity comparable to antibiotics, with a directly proportional relationship of venom concentration and GIZ, though, they were more efficient in combatting resistant types of bacteria. Both venoms and the standard antibiotic, showed no antifungal benefits.