Production of Antimicrobial Pyrrol-Derevatives Acting Against Some Fish Pathogens from Marine Bacillus pumilus MMM

摘要

The need for the development of new antimicrobials to overcome drug resistance in bacterialpathogens has been stressed by various researchers worldwide. Working on marine microbial resources maylead to the discovery of an alternative antimicrobial agents added to the commercial used ones. In this studyseveral marine bacterial isolates were screened for their ability to produce anti-microbial agent(s) againstAeromonas Hydrophila using agar well diffusion method. The potent antimicrobial producer was isolated fromthe western harbor of Alexandria and identified as Bacillus pumilus MMM using the 16S rRNA gene sequence,it showed inhibition zone of 20mm. The optimization process was performed using the Plackett –Burmanexperimental design. The optimized luria broth culture medium increased the antimicrobial activity, the inhibitionzone was 30 mm. The extraction was proceeded using ethyl acetate, it led to more antimicrobial activity theinhibition zone was 33 mm. Partial characterization of the ethyl-acetate extract of Bacillus pumilus MMM wasperformed using the GC Ms spectrophotometry, this analysis indicated the most probable effective compoundas anti-microbial agent according to the obtained data was pyrrolo [1, 2-a] pyrazine-1, 4-dione derivatives. Itshowed also inhibitory effect against Vibrio parahemolyticus, Pseudomonas aeruginosa and Staph aureus.The mode of action of this pyrrolo- derivatives secondary metabolite on the Aeromonas hydrophila cells wasestimated though the Transmission Electronic Microscope (TEM) examination it led to a rupture in the bacterialcell wall, intracellular granulation and a sever damage for the nucleus compared to the untreated cells.