Abstract
Bacillus licheniformis KSAWD3, isolated from sea water of Arabian Gulf, Tarut Island of east Coast of Saudi Arabia, was selected as a potential strain that showed considerable bioactivity from amongst 300 isolates. The isolate was identified based on morphological, biochemical and gene sequence of 16sRNA. This bacterium showed inhibitory activity against ATCC reference strains and clinical pathogens obtained from Military Hospital in Riyadh. The tested pathogens included Salmonella enterica subsp enterica serovar Typhimurium (ATCC 13311), Shigella sonnei (ATCC 11060), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 15442), Staphylococcus aureus subsp. aureus (ATCC 6538P, 25923, & 33591), Streptococcus pneumoniae, Haemophilus influenzae, Salmonella sp. Campylobacter jejuni and Streptococcus pyogens. Bioactivity was tested employing cross streaking, agar well diffusion method, agar overlay method, and assay of growth inhibition in broth. This isolate showed broad spectrum of growth inhibition by recording inhibition of growth against more than one pathogen. It was observed that the culture filtrate of B. licheniformis KSAWD3 showed considerable inhibition against the pathogens which showed resistance against chloremphenicol, gentamycin, tetracycline, penicillin, neomycin, and ampicillin. Results indicate scope for deriving potential bioactive principles from this marine B. lichenifirmis of Arabian Gulf for use against the well known human pathogens.