Isolation of an antibiotic producer Pseudomonas sp. from the Persian Gulf

ObjectiveTo investigate the isolation of marine antibiotic-producing bacteria from the Persian Gulf, as an untapped source for searching new natural antibiotics.MethodsInitially water and sediment samples were collected from 18 study sites in the some northern areas of Persian Gulf. All of the bacterial isolates using Marine Agar 2216 were inoculated into Marine broth and incubated on a rotary shaker at 28 °C for 2-7 days. Bioactivity of their ethyl acetate extract was assessed at 100 mg/mL concentration in disc diffusion method against 6 gram-positive and 5 gram-negative bacteria. Synthetic antibiotics were used as control.ResultsAltogether, 46 bacterial colonies were isolated. Only one isolate from a marine sediment sample collected at a depth of 10 m, identified as Pseudomonas aeruginosa PG-01, was exhibited the capability of antibiotic production. The obtained raw extract from intended bacterium was effective against all tested gram positive bacteria while gram negative bacteria were resistance. Methicillin resisitant Stapuylococcus aureus (MRSA), Streptococcus pyogenes (S. pyogenes), Staphylococcus epidermidis (S. epidermidis) and Bacillus cereus (B. cereus) were the most sensitive strains. All of tested pathogens were multidrug resistant. The antibacterial compound from this bacterium was active even at 120 °C. The optimized temperature and time for antibacterial metabolite production were 37 °C and 72 hrs, respectively.ConclusionsConsidering the antibacterial effect of Pseudomonas aeruginosa PG-01 especially against MRSA, it can be regarded the intended bacterium as a valuable strain and can give hope for treatment of diseases caused by multidrug resistant bacteria.