title: Effect of frequent consumption of a Lactobacillus casei-containing milk drink in Helicobacter pylori-colonized subjects.
abstract: BACKGROUND
  Several studies have reported inhibitory effects of lactic acid bacteria on bacterial pathogens.
  
  
  OBJECTIVE
  To test whether a drink containing Lactobacillus casei strain Shirota inhibits Helicobacter pylori growth.
  
  
  METHODS
  The in vitro growth inhibition of H. pylori was studied when L. casei was added to plates previously inoculated with H. pylori reference strain NCTC 11637. In an intervention study, 14 H. pylori-positive subjects were given Yakult drink (10(8) colony-forming units/mL L. casei) thrice daily during meals for 3 weeks. Six untreated H. pylori-positive subjects served as controls. H. pylori bacterial loads were determined using the 13C-urea breath test, which was performed before and 3 weeks after the start of L. casei supplementation.
  
  
  RESULTS
  In vitro, L. casei inhibits H. pylori growth. This effect was stronger with L. casei grown in milk solution than in DeMan-Rogosa-Sharpe medium. No growth inhibition was shown with medium inoculated with lactic acid, Escherichia coli strain DH5alpha or uninoculated medium. Filtration of L. casei culture before incubation with H. pylori completely abolished the inhibitory effect. Urease activity decreased in nine of the 14 (64%) subjects with L. casei supplementation and in two of the six (33%) controls (P = 0.22).
  
  
  CONCLUSIONS
  Viable L. casei are required for H. pylori growth inhibition. This does not result from changes in lactic acid concentration. In addition, a slight, but non-significant, trend towards a suppressive effect of L. casei on H. pylori in vivo may exist.
authors.affiliation: Department of Gastroenterology and Hepatology, Academic Hospital Vrije Universiteit, Amsterdam, The Netherlands. a.cats@nki.nl
authors.forename: A
authors.initials: A
authors.lastname: Cats
authors.forename: E J
authors.initials: EJ
authors.lastname: Kuipers
authors.forename: M A R
authors.initials: MA
authors.lastname: Bosschaert
authors.forename: R G J
authors.initials: RG
authors.lastname: Pot
authors.forename: C M J E
authors.initials: CM
authors.lastname: Vandenbroucke-Grauls
authors.forename: J G
authors.initials: JG
authors.lastname: Kusters
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001628:Beverages; D019587:Dietary Supplements; D005260:Female; D016481:Helicobacter Infections / Q000201:enzymology / Q000517:prevention & control*; D016480:Helicobacter pylori / Q000254:growth & development*; D006801:Humans; D007780:Lacticaseibacillus casei / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D008892:Milk / Q000382:microbiology; D014510:Urease / Q000378:metabolism
chemical_list: D014510:Urease