Assessment of Probiotic Potential of Lactobacillus Strains Isolated from Animal Sources

Abstract

Human gut is a rich niche for thousands of bacterial species. Among them a lot of species are characterized as beneficial, friendly bacteria due to the numerous ―benefits‖ they provide to the host system. These bacteria are called ―Probiotics‖ and consist mainly of the broad group of bacteria i.e. lactic acid bacteria including genus Lactobacillus, Bifidobacterium, Streptococcus and Enterococcus. The sources for probiotic strains is wide, ranging from dairy products, fruits and vegetables to animal gut and human feaces. In this study, lactic acid bacteria were isolated from sheep and cow feaces. Initial biochemical testing and 16S rRNA gene sequencing confirmed these strains as Lactobacillus plantarum and Lactobacillus rhamnosus. These strains were further evaluated for their probiotic potential by assessing their antimicrobial activities against three different pathogenic strains and also checking their safety through in vivo rat model. Both strains showed good antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi. Survival of these strains in the feaces of rat models showed their adhesion and colonization ability in the GIT whereas no harmful effect was observed in rats during the experiment. These positive results make both Lactobacillus plantarum and Lactobacillus rhamnosus potential probiotic candidates.