Isolation, Identification, and Evaluation of Novel Probiotic Strains Isolated from Feces of Breast-Fed Infants
Marutpong Panya PhD*,**, Viraphong Lulitanond PhD**, Pongsak Rattanachaikunsopon PhD***, Thanyakarn Srivoramas MSc*, Tarinee Chaiwong PhD*
Affiliation : * College of Medicine and Public Health, Ubon Ratchathani University, Ubon Ratchathani, Thailand ** Research and Diagnostic Center for Emerging Infectious Diseases, Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen , Thailand *** Department of Biological Science, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, Thailand
Objective : To isolate, identify, and evaluate the probiotic properties of lactic acid bacteria (LAB) isolated from the feces of
breast-fed infants.
Material and Method: The probiotic tests included investigation of hemolysis activity, survival in simulated gastrointestinal
tract conditions (acid and bile salt tolerance), susceptibility to antibiotics, and ability to inhibit selected bacterial pathogens
(Escherichia coli O157:H7, Vibrio cholerae and Salmonella enterica subsp enterica serovar Typhimurium). The bacterial
species identification was performed by both carbohydrate utilization and partial 16S ribosomal RNA sequencing.
Results : Five of fifty LAB isolates (UBU-03, UBU-06, UBU-09, UBU-34, and UBU-37) showed good probiotic properties.
These five isolates showed non-hemolysis type (gamma-hemolysis), susceptibility to all antibiotics tested except for vancomycin,
ability to survive in the simulated gastrointestinal conditions of both acid and bile salt solution, and ability to inhibit growth
of E. coli O157: H7 and V. cholerae. Bacterial species identification revealed that all five isolates were firmly identified as
Lactobacillus rhamnosus species.
Conclusion : The L. rhamnosus strains that were isolated and characterized in this study could be considered as probiotic
strains, and then used for further probiotic characterization in human cell cultures or animal models.
Keywords : Breast-fed infant, Lactic acid bacteria, Lactobacillus rhamnosus, Probiotic
