The effectiveness of novel bacteriocin derived from Escherichia coli colonized in the fermented pineapple Ananas comosus (L.) Merr. against pathogenic bacteria isolated from aquaculture sites

Aim: The aim was to evaluate antimicrobial property of bacteriocin isolated from Escherichia coli against pathogenic bacteria from aquaculture sites. Materials and Methods: E. coli was isolated from fermented pineapple Ananas comosus using eosin methylene blue agar. The antimicrobial activity of the isolated E. coli was screened using hole-plate diffusion method. The bacterial strain that showed the widest inhibition zone was selected and grown in tryptic soy broth, followed by partial purification of bacteriocin by using ammonium sulphate. Bacteriocin derived from the E. coli was subjected to the antimicrobial test against 55 bacteria strains namely Aeromonas hydrophila (n=10), Citrobacter freundii (n=5), Edwardsiella tarda (n=10), Flavobacterium spp. (n=10), Pseudomonas spp. (n=10), Vibrio parahaemolyticus (n=5) and Vibrio alginolyticus (n=5) by using twofold broth microdilution method to determine minimum inhibitory concentration (MIC) values of the bacteriocin against the tested bacteria. Results: The results of the present study showed that the MIC values of the partially purified bacteriocin against present pathogenic bacteria isolates ranged from 7.81 to 31.25 ppm whereas the MIC values of kanamycin (positive control) ranged from 15.63 to 125 ppm. Conclusion: The results of the present study showed the bacteriocin derived from E. coli can control all the present bacterial isolates indicating the huge potential of the bacteriocin as a new antimicrobial agent for aquaculture uses.