Lactobacilli in human dental caries and saliva

Samples (98 plaque and 72 saliva) from 93 patients with dental caries were investigated for Lactobacillus species which comprised 65 (62.5%)) of 104 i solates. Yeasts (20.1%), Streptococcus spp. (8.7%), Staphylococcus spp. (2. 9%) and a few unidentified species (5.8%), were also found. The Lactobacill us isolates were L. brevis (24.6%) L, fermentum (18.5%) L. casei(16.9%), L. delbrueckii (15.4%), L. plantarum (9.23%), L. acidophilus (7.69%), L. jens enii (4.62%), L. salivarius (1.54%) and L. gasseri(1.54%). The most common species was L. brevis (24.6%). The strains tested for beta-lactamase produc tion showed 75.4% positive. All the Lactobacillus strains were tested for b acteriocin production against Escherichia coil, Salmonella spp., Shigella d ysenteriae, S. sonnei, Klebsiella spp. and Campylobacter sp. All the lactob acilli except L. jensenii produced bacteriocin against at least one of the indicator organisms. The involvement of Lactobacillus in dental caries was established, although its role and mechanism is not well understood. The ab ility of Lactobacillus spp. to protect their host against certain diseases by inhibiting the growth of potential pathogens was evident.