title: Evaluation of resistance to low pH and bile salts of human Lactobacillus spp. isolates.
abstract: There are nearly 100 trillion bacteria in the intestine that together form the intestinal microbiota. They are 'good' bacteria because they help to maintain a physiological balance and are called probiotics. Probiotics must have some important characteristics: be safe for humans, be resistant to the low pH in the stomach, as well as bile salts and pancreatic juice. Indeed, their survival is the most important factor, so that they can arrive alive in the intestine and are able to form colonies, at least temporarily. The aim of our study was the evaluation of resistance of Lactobacillus isolates from fecal and oral swabs compared to that found in a commercial product. Seven strains were randomly chosen: L. jensenii, L. gasseri, L. salivarius, L. fermentum, L. rhamnosus, L. crispatus, and L. delbrueckii. We observed a large variability in the results: L. gasseri and L. fermentum were the most resistance to low pH, while only L. gasseri showed the best survival rate to bile salts. Interestingly, the commercial product did not show tolerance to both low pH and bile salts.
authors.affiliation: Department of Biomedical and Biotechnological Sciences, Microbiology section, University of Catania, Catania, Italy.
authors.forename: Virginia
authors.initials: V
authors.lastname: Fuochi
authors.affiliation: Department of Biomedical and Biotechnological Sciences, Microbiology section, University of Catania, Catania, Italy IRCCS San Raffaele Pisana, BioBIM - Interinstitutional Multidisciplinary BioBank, Rome, Italy.
authors.forename: Giulio Petronio
authors.initials: GP
authors.lastname: Petronio
authors.affiliation: Department of Biomedical and Biotechnological Sciences, Microbiology section, University of Catania, Catania, Italy Department of Public Health and Infectious Diseases, "Sapienza" University of Rome, Italy.
authors.forename: Edmondo
authors.initials: E
authors.lastname: Lissandrello
authors.affiliation: Department of Biomedical and Biotechnological Sciences, Microbiology section, University of Catania, Catania, Italy furneri@unict.it.
authors.forename: Pio Maria
authors.initials: PM
authors.lastname: Furneri
mesh_terms: D001647:Bile Acids and Salts / Q000378:metabolism*; D005243:Feces / Q000382:microbiology; D000069196:Gastrointestinal Microbiome / Q000502:physiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007778:Lactobacillus / Q000302:isolation & purification / Q000502:physiology*; D009055:Mouth / Q000382:microbiology; D019936:Probiotics / Q000737:chemistry
chemical_list: D001647:Bile Acids and Salts
keywords: Lactobacillus; bile salts; low pH; probiotic; resistance