Isolation of antibiotics producing bacteria from marine soil and comparative analysis of same with commercially available drugs

The isolation of antibiotic producing bacteria from marine soil and comparative analysis of same with ciprofloxacin and amoxicillin against staphylococcus aureus and Escherichia coli was carried out in a Microbiology Laboratory of Chukwuemeka Odumegwu Ojukwu University, Uli. This was done to isolate antibiotic producing bacteria and compare same with existing commercially available antibiotics with a view to using marine soil in the treatment of common bacterial infections. Soil samples were collected from Bonny Island Sea, Port Harcourt. One gram of mixed soil sample was serially diluted and spread-plated on nutrient agar plates. The representative isolates obtained were sub-cultured to get a pure culture. Morphological, biochemical, physiological characteristics of the bacteria were analyzed. Agar well diffusion was carried out. One isolate had a substantial antibacterial activity with 3.5mm zone of inhibition against two test bacteria used in the preliminary screening. The isolate was marked as Streptomyces (STR I) and was identified as Streptomyces griseus while other isolates did not show any antibacterial activity. Ciprofloxacin showed the highest antibacterial activity to both Staphylococcus aureus and Escherichia coli of 3.7mm and 4.0mm respectively while Amoxicillin showed antibacterial activity of 3.5mm and 2.7mm respectively. This reveals that antibiotic producing bacteria from marine soil are also effective in antimicrobial activity and could be used for antimicrobial chemotherapy.