Nabi Jomehzadeh1, Mansour Amin2, Morteza Saki3, Hajar Hamidi4, Maryam Seyedmahmoudi4, Zahra Gorjian5, Mina Moghaddam4, Hazhir Javaherizadeh6. 1. Abadan Faculty of Medical Sciences, Abadan, Iran; Infectious and Tropical Disease Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of Microbiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. 2. Infectious and Tropical Disease Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of Microbiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. 3. Infectious and Tropical Disease Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of Microbiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Student Research Committee, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. 4. Department of Microbiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. 5. Abadan Faculty of Medical Sciences, Abadan, Iran. 6. Abuzar Children's Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Alimentary Tract Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Electronic address: javaherizadehajir@gmail.com.
Abstract
OBJECTIVES: To evaluate the potential probiotic properties ofLactobacillus strains isolated from feces of infants and also to determine their antimicrobial activity against some enteropathogenic bacteria. METHODS: The Fecal samples were prepared from 120 infants aged less than 24 months. In total,105 Lactobacillus strains were identified by phenotypic tests. Thirty isolates were randomly selected to study their potential probiotic properties. These isolates were examined for resistance to acid (pH: 2.5, 2 h) and bile (oxgall 0.3%, 8 h), adhesion to HT-29 cells, antibiotic susceptibility, and antimicrobial activities. RESULTS: On basis of 16S rRNA sequencing, 30 isolates identified as Lactobacillus fermentum (n = 11; 36.7%), Lactobacillus plantarum (n = 9; 30%), Lactobacillus rhamnosus (n = 6; 20%), and Lactobacillus paracasei (n = 4; 13.3%). All tested strains survived at acid and bile conditions. Six Lactobacillus strains revealed high adherence to HT-29 cells. Three strains including the L. fermentum (N2, N7), and the L. plantarum (N20) showed good probiotic potential and inhibited the growth of Yersinia enterocolitica ATCC 23715, Shigella flexneri ATCC 12022, Salmonella enterica ATCC 9270, and enteropathogenic Escherichia coli (EPEC) ATCC 43887. The antibiotic resistance test showed that all the isolates were susceptible to tetracycline, and chloramphenicol. CONCLUSIONS: Lactobacillus strains like L. fermentum (N2, N7), and the L. plantarum (N20), could be potential probiotic, but further in vitro and in vivo studies on these probiotic strains are still required.
OBJECTIVES: To evaluate the potential probiotic properties ofLactobacillus strains isolated from feces of infants and also to determine their antimicrobial activity against some enteropathogenic bacteria. METHODS: The Fecal samples were prepared from 120 infants aged less than 24 months. In total,105 Lactobacillus strains were identified by phenotypic tests. Thirty isolates were randomly selected to study their potential probiotic properties. These isolates were examined for resistance to acid (pH: 2.5, 2 h) and bile (oxgall 0.3%, 8 h), adhesion to HT-29 cells, antibiotic susceptibility, and antimicrobial activities. RESULTS: On basis of 16S rRNA sequencing, 30 isolates identified as Lactobacillus fermentum (n = 11; 36.7%), Lactobacillus plantarum (n = 9; 30%), Lactobacillus rhamnosus (n = 6; 20%), and Lactobacillus paracasei (n = 4; 13.3%). All tested strains survived at acid and bile conditions. Six Lactobacillus strains revealed high adherence to HT-29 cells. Three strains including the L. fermentum (N2, N7), and the L. plantarum (N20) showed good probiotic potential and inhibited the growth of Yersinia enterocolitica ATCC 23715, Shigella flexneri ATCC 12022, Salmonella enterica ATCC 9270, and enteropathogenic Escherichia coli (EPEC) ATCC 43887. The antibiotic resistance test showed that all the isolates were susceptible to tetracycline, and chloramphenicol. CONCLUSIONS:Lactobacillus strains like L. fermentum (N2, N7), and the L. plantarum (N20), could be potential probiotic, but further in vitro and in vivo studies on these probiotic strains are still required.