ANTIBIOTIC ACTIVITY AND SUSCEPTIBILITY OF NOVEL PONTIBACTER SPS., ISOLATED FROM LABEO ROHITA
Article history Aim: The present investigation was to explore the unexploited application of novel fish gut bacteria Pontibacter sps as an antibacterial and antifungal drug. Methods and Results: The isolate is a gram negative, non motile, red pigmented, rod shaped bacterium, designated as strain PROLR15 T . The strain PROLR15 T produces a distinct red color pigmentation which makes it different from the other Pontibacters. The 16S rRNA sequence analysis showed 92% similarity with an existing existing Pontibacter korlensis strain. The major cellular fatty acids were Iso-c15:0 and Iso c17:0 3OH. Predominant menaquinone of the strain is MK-7. It produces extracellular polymeric substances under anaerobic condition which portraits its facultative anaerobic nature. Phylogenetic studies and the phenotypic characterizations strongly support the idea that the isolated bacterium belongs to the genus Pontibacter. (HQ005734). Pontibacter sps possess antimicrobial activity. Conclusion: Among the pathogenic species Salmonella typhii, Klebsiella pneumonia and Staphylococcus aureus were most susceptible at minimum concentration. Most of the pathogenic fungi were susceptible to the isolated bacteria Pontibacter sps., with the MIC90 below 5000 µg/mL. Significance: Antimicrobial activity against most serious disease causing pathogens and susceptibility to most of the antibiotics paves way to utilize them for treatment of diseases and as a probiotic supplement.