title: PCR detection of Bifidobacterium strains and Streptococcus thermophilus in feces of human subjects after oral bacteriotherapy and yogurt consumption.
abstract: Streptococcus thermophilus, Bifidobacterium infantis Y1 and Bifidobacterium breve Y8 strains were identified and enumerated by PCR assay in human fecal samples after intake of the pharmaceutical preparation VSL-3 or yogurt. ThI/ThII primer set, specific for S. thermophilus, was selected testing its specificity against several strains of enterococci, streptococci and other genera colonizing the human intestine. A culture-independent PCR protocol, developed in this study, allowed to directly detect and enumerate S. thermophilus in human feces, excluding culture-based techniques or time consuming DNA isolation and purification procedures. Intestinal persistence of S. thermophilus was studied in feces of 10 healthy subjects given VSL-3 or yogurt. Streptococcal population was detected after 3 days of administration and persisted for 6 days after the treatment suspension. In the same trial, the colonization kinetics of B. infantis Y1 and B. breve Y8 were studied by amplification of colonies with the strain-specific primer sets InfY-BV.L/R and BreY-BV.R/L, showing a host-dependent transient colonization behaviour. PCR analysis of feces from 10 patients affected by inflammatory bowel diseases (IBD) and treated with VSL-3 for 2 months showed a colonization pattern of S. thermophilus, B. infantis Y1 and B. breve Y8 similar to that observed with the healthy subjects.
authors.affiliation: Department of Pharmaceutical Sciences, Via Belmeloro 6, University of Bologna, 40126, Bologna, Italy. patbri@alma.unibo.it
authors.forename: Patrizia
authors.initials: P
authors.lastname: Brigidi
authors.forename: Erwin
authors.initials: E
authors.lastname: Swennen
authors.forename: Beatrice
authors.initials: B
authors.lastname: Vitali
authors.forename: Maddalena
authors.initials: M
authors.lastname: Rossi
authors.forename: Diego
authors.initials: D
authors.lastname: Matteuzzi
mesh_terms: D001644:Bifidobacterium / Q000235:genetics / Q000302:isolation & purification*; D015169:Colony Count, Microbial / Q000379:methods; D017931:DNA Primers; D005243:Feces / Q000382:microbiology*; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000379:methods*; D019936:Probiotics; D013291:Streptococcus / Q000235:genetics / Q000302:isolation & purification*; D015014:Yogurt / Q000382:microbiology*
chemical_list: D017931:DNA Primers