Genetic diversity of Lactobacillus spp. isolates from oral cavity and their probiotic and antimicrobial properties

The kind of used food is effective on diversity of Lactobacillus biota in the oral cavity. Dairy products are major sources of probiotics including lactobacillus. Probably, these lactobacillus species have probiotics properties and they could benefit human health. In this study, consumers of domestic dairy products were selected and Lactobacillus spp. from their oral cavity were isolated and probiotic potential of these bacteria were investigated. Saliva samples were collected from one hundred people and cultured on MRS agar. Samples were incubated in anaerobic condition. Thirty predominant species from 100 persons were isolated and selected for probiotics properties assay by growth at gastric and gastrointestinal conditions (acid pH 3 and bile 0.3 w/v conditions respectively). Antibiotic susceptibility profile and antimicrobial activity of the isolates were defined. Predominant species were L. gasseri (53%) followed by L. fermentum and L. salivarius. All isolates were susceptible to Tigecycline, Penicillin, Tetracyclin and Ticaracillin. In addition, all isolates were resistance to Co-trimoxazole and Tobramycin. Acid resistance rate was higher than bile resistance. In addition, 26% of the isolates were resistant to acid and bile salt, which indicates good probiotic potential. Eight isolates had inhibitory activity against bacterial growth including L. gasseri, L. salivarius, L. crispatus and L. curvatus. The higher antimicrobial activity was showed by L. gasseri (five isolates) against Bacillus cereus. Therefore, some of these Lactobacillus species like of L. gasseri can be good candidate to inhibit of B. cereus growth in foods.