This study evaluated the effect of a Probiotic mouthrinse containing nisin, a bacteriocin extracted from Lactococcus lactis on dental plaque and gingivitis in young adult population. A group of 32 subjects were randomly assigned into two groups of 16 each. The first group started using the control mouthrinse (placebo) for 2 weeks followed by a washout period of 4 weeks. This group then used the test mouthrinse (Probiotic) for a further duration of 2 weeks. The second group followed a similar protocol as the first except that this group started with the test mouthrinse (Probiotic). Plaque Index (PI) and Gingival Index (GI) were recorded at baseline and after 2 weeks for each group. All subjects were given full mouth prophylaxis after each measurements. The results of this study showed that rinsing with Probiotic mouthrinse resulted in a statistically significant reduction of plaque accumulation and gingivitis compared to rinsing with placebo. The results indicated that Probiotic mouthrinse containing nisin had the potential of inhibiting plaque accumulation and was effective in reducing gingivitis.
In this study, a Lactic acid bacteria (LAB) strain was isolated on MRS medium from gastro-intestinal tissues of Broadhead catfish (Clarias macrocephalus). Out of 50 isolates, 25 isolates were found to be positive on lactose utilisation test and were identified to be gram positive cocci. Using disc diffusion methods, one out of 22 isolates, i.e., a strain A5 demonstrated inhibitions against three indicator organisms; Bacillus cereus, Staphylococcus aureus and Salmonella thyphimurium. Partial 16S rDNA sequencing identified isolate A5 as a member of Lactococcus lactis, with 100% DNA homology. Cell free supernatant fluid from Lactococcus lactis A5 showed inhibitory activities against both gram positive pathogens (Bacillus cereus and Staphylococcus aureus) and gram negative pathogens (Salmonella thyphimurium). Chloroform precipitated bacteriocin retained antagonistic activities in the presence of catalase and lysozyme; and was completely inactivated by Proteinase K treatment. The bacteriocin has a molecular weight of 3.4 kDa, based on SDS-PAGE analysis and the extract was heat stable at 37°C and 65°C, for 15 minutes. The antibacterial activity was suppressed with the addition of EDTA but was significantly increased with the addition of SDS, Triton X-100, Tween 20 and Tween 80. This bacteriocin belongs to class 1 bacteriocin, which was shown to have a nisin-like properties. This strain can be used as potential probiotics in animal or aquaculture feeding; and the bacteriocin it produces will be useful in food preservative.