Molecular study and probiotic potency of lactic acid bacteria isolated from dairy products in Mazandaran province of Iran and it antagonistic effect on Pseudomonas aeruginosa

Document Type : Research Article


1 Microbiology Group, Biological Sciences Faculty, North Tehran Branch of Islamic Azad University, Tehran, Iran

2 Microbiology Group, Biological Sciences Faculty, Center Tehran Branch of Islamic Azad University, Tehran, Iran


Probiotics are living dietary supplements that exert their health benefits by improving the intestinal microbial balance in the host. lactic acid bacteria are the most common type of bacteria that have been identified as probiotics.
Materials and Methods: This study isolated lactic acid bacteria from the traditional yogurt, dooghd and, curd of Mazandaran Province in Iran and investigated their probiotic potency and antimicrobial effect on Pseudomonas aeruginosa. lactic acid bacteria were isolated by phenotypic and biochemical tests of acid resistance and bile salt tolerance tests, and their primary probiotic index was evaluated. Tube dilution and turbidimetry were used to determine the minimum inhibitory concentration of antimicrobial substances. The inhibitory effect of the isolated bacteria on P. aeruginosa was investigated by the disk-diffusion agar method. The non-growth halo diameter was measured around the disk. In order to reduce errors, each test was repeated at least three times, and the mean non-growth halo diameter was measured on Mueller-Hinton agar and its antagonistic effect was investigated.
Results: The findings showed that adding a lactobacillus dose increases its inhibitory effects. The Lactobacillus plantarum were identified using specific primer pairs of the 16S rRNA gene, the established specific band, and PCR product sequencing. Rec A gene PCR was performed for differentiating the members of this group using specific primers and five L. plantarum strains were identified.
Conclusion: According to the results of this study, lactobacilli were well able to inhibit the growth of pathogenetic strains. In this study, L. plantarum had an inhibitory effect on