Antibacterial activity of marine bacillus substances against Vibrio cholerae and Staphylococcus aureus and in vivo evaluation using embryonic zebrafish test system

Abstract

Cell free extracts of Bacillus subtilis subsp. spizizenii and B. thuringiensis isolated from hydrothermal vent region of Azorean Island Faial, North Atlantic Ocean showed antagonistic against Vibrio cholera serogroup 01 and Staphylococcus aureus, respectively. The in vitro inhibition of infectious pathogens by both B. subtilis subsp. spizizenii and B. thuringiensis was concentration dependent. The result of sensitivity to protease test showed considerable reduction of antibacterial activity for both Bacillus strains, indicating the proteinaceous nature of the antibacterial substances. Further, our results on antibacterial substance of heat-resistant, proteinaceous nature and bacteriostatic mode of action was evaluated for the toxicity studies using zebrafish animal model, an alternative to the use of antibiotics test against infectious diseases. Bacillus antibacterial extracts showed no toxic effects with the Staphylococcus aureus-zebra fish embryo infection studies.