EVALUATION OF THE ANTIMYCOBACTERIAL AND ANTIMYCOLACTONE EFFICACY OF KOMBUCHA

ABSTRACT Buruli ulcer is caused by mycolactone, a toxin produced by Mycobacterium ulcerans. Drug development for the treatment of the disease and early diagnosis is greatly hampered by the lipid nature of the mycolactone and bacterial resistance to currently used antimycobacterials. Kombucha tea is a health drink consumed worldwide. Research has shown that Kombucha exerts medicinal properties including enhanced wound healing and antimicrobial activity. This study was aimed at characterizing the microbial content of Kombucha tea, assessing Kombucha antimicrobial, antimycobacterial and mycolactone inactivating potential. The antioxidants as well as the phytochemical constituents of the tea were also investigated. Kombucha tea was cultured, and microbial isolates were Gram stained, DNA extracted, followed by PCR with 16S rRNA and fungal ITS primers for identification of bacteria and yeasts, respectively. Resulting amplicons were sequenced and blasted against the PUBMED database for identification based on sequence similarity and homology. Phytochemical analysis was conducted on the Kombucha tea and the total phenolic content were determined. DPPH assay was used for the determination of the antioxidant property of the tea. Different concentrations of the tea were co-incubated with mycolactone for various time points to observe for toxin attenuation. The presence of intact or inactivated mycolactone was detected using TLC and cytotoxicity assays on cultured human fibroblast cell lines. Antimicrobial potency of increasing concentrations of the tea was tested against S. aureus and M. ulcerans by pre-incubation prior to microscopy and culture to observe morphological changes and viability respectively. Yeasts in the Kombucha tea were identified as Dekkera bruxellensis, Brettanomyces bruxellensis, Rhodotorula mucilaginosa and Lachancea fermentati and the bacteria as Paenibacillus lactis, Paenibacillus cineris Bacillus licheniformis, Lactobacillus amylolyticus and Corynebacterium glutamic. Phytochemicals detected in the tea were saponins, flavonoids, alkaloids, phenols and terpenoids. The antioxidant property of Kombucha was higher as compared to the unfermented  tea and a similar effect was observed with the phenolic content. Unfermented was 2-fold less potent in total phenolic content than Kombucha tea. The tea possessed antimicrobial activity against S. aureus but not on M. ulcerans. Kombucha was not cytotoxic to the human skin fibroblast cells, however, mycolactone treated with Kombucha tea retained its potency against human fibroblast cell lines and viable bacilli of M. ulcerans were observed after Kombucha treatment. Kombucha tea possesses antioxidant and antimicrobial activities but lacks antimycobacterial and antimycolactone activity.