QUORUM QUENCHING POTENTIALS OF PROBIOTIC ENTEROCOCCUS DURANS LAB38 AGAINST METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS

Objective: he focus of this study was to explore the nuance strategy to combat the virulence factors of the pathogens by probiotic Enterococcus durans LAB38Methods: Probiotic attributes was determined by bile salt tolerance (0.5%) and Artemia gnotobiotic assay. Quorum sensing (QS) inhibitory activity of the supernatant and ethyl acetate (EA) extract of LAB38 was evaluated by using the indicator strains, includes Chromobacterium violaceum CV026 (mini-Tn5 mutant of ATCC 31532), methicillin resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PA). Reporter strains, Vibrio harveyi BB170 (luxN mutant), BB886 (luxP mutant) and Escherichia coli pSB401 (pACYC184- derived) were used for bioluminescence-based target specificity analysis. GC-MS analysis of EA extract was performed using standard protocol. Results: LAB38 has shown bile salt tolerance and positive probiotic effect towards Artemia salina. In addition, 100 µg/ml EA extract has significantly reduced the violacein production (37 ± 1.4%) in CV026, biofilm formation in MRSA (94 ± 0.9 %) and PA (22 ± 0.08%). Further, 200 µg/ml of EA extract has shown inhibition against both autoinducer-1 and autoinducer-2 mediated QS system. Bioluminescence inhibition is directly proportional to the time of exposure. GC-MS result revealed that bromine, sulphur containing molecule and azulene derivative were found in the EA extract.Conclusion This is the first report on probiotic Enterococcus durans for quorum quenching activity. Hence, the bacterium could be used for future therapeutics application. Keywords: Autoinducer, Biofilm, Methicillin resistant Staphylococcus aureus, Quorum quenching, Probiotics, CV026.

STUDIES ON THE EFFECTS OF PHAGOCYTIC STIMULATION ON MICROBIAL DISEASE: IV. THE INFLUENCE OF 1,4-DIMETHYL-7-ISOPROPYLAZULENE WITH AND WITHOUT DIHYDROSTREPTOMYCIN ON EXPERIMENTAL TUBERCULOSIS IN GUINEA PIGS

The outcome of experimental tuberculosis in guinea pigs was favorably influenced by treatment with 1,4-dimethyl-7-isopropylazulene. This compound had no antituberculous properties in vitro, but stimulates phagocytic activity of cells of the reticulo-endothelial system. Effects of simultaneous treatment with the azulene derivative and dihydrostreptomycin on well-established tuberculosis were similarly studied. Therapeutical effect of dihydrostreptomycin was significantly increased by the simultaneous treatment with the azulene. This experiment brought evidence that the host–parasite relationship in experimental tuberculosis can be favorably influenced for the benefit of the host by appropriate treatment acting against the parasite and simultaneously stimulating the defense mechanism of the host. The authors discuss the need for more research in tuberculosis therapy directed toward finding ways of stimulating the cell-linked defense mechanism of the host against bacterial invaders.