title: Absence of efficacy of nonviable Lactobacillus acidophilus for the prevention of traveler's diarrhea: a randomized, double-blind, controlled study.
abstract: BACKGROUND
  Diarrhea is the most common illness associated with international tourism. We evaluated the efficacy of a probiotic preparation of nonviable Lactobacillus acidophilus (hereafter referred to as LA) for the prevention of traveler's diarrhea.
  
  
  METHODS
  We conducted a randomized, double-blind, controlled trial. Travelers were randomized to receive either LA or placebo twice daily from 1 day before their departure to 3 days after their return. On each day of the trip and the week following the return, travelers had to record the number and consistency of stools and their adherence to the treatment. Diarrhea was defined as > or =3 unformed stools in a 24-h period.
  
  
  RESULTS
  From January 2001 to September 2004, a total of 174 subjects were randomized to each treatment group. Half of the travelers went to West Africa, and organized tours or backpacking were the most common modes of traveling. The incidence of diarrhea did not differ between the 2 groups; it was 61.4 cases per 100 person-months in the LA group (95% confidence interval [CI], 44.1-85.5) and 43.4 cases per 100 person-months in the placebo group (95% CI, 30.0-62.9) (P=.14). Adjustment for travel duration and other variables did not reveal any difference between the 2 groups (adjusted hazard ratios comparing the LA and placebo groups were 1.43 [95% CI, 0.87-2.36] in an intent-to-treat analysis and 1.38 [95% CI, 0.79-2.39] in an efficacy analysis).
  
  
  CONCLUSIONS
  There was no beneficial effect of treatment with LA for the prevention of travelers' diarrhea. More studies are required to assess the efficacy of other specific probiotics (e.g., a Lactobacillus rhamnosus GG preparation) for preventing traveler's diarrhea.
authors.affiliation: Emerging Diseases Epidemiology Unit, Institut Pasteur, Paris, France. vale.briand@laposte.net
authors.forename: Valérie
authors.initials: V
authors.lastname: Briand
authors.forename: Pierre
authors.initials: P
authors.lastname: Buffet
authors.forename: Sabine
authors.initials: S
authors.lastname: Genty
authors.forename: Karine
authors.initials: K
authors.lastname: Lacombe
authors.forename: Nadine
authors.initials: N
authors.lastname: Godineau
authors.forename: Jérome
authors.initials: J
authors.lastname: Salomon
authors.forename: Eric
authors.initials: E
authors.lastname: Vandemelbrouck
authors.forename: Pascal
authors.initials: P
authors.lastname: Ralaimazava
authors.forename: Catherine
authors.initials: C
authors.lastname: Goujon
authors.forename: Sophie
authors.initials: S
authors.lastname: Matheron
authors.forename: Arnaud
authors.initials: A
authors.lastname: Fontanet
authors.forename: Olivier
authors.initials: O
authors.lastname: Bouchaud
mesh_terms: D003967:Diarrhea / Q000517:prevention & control*; D004311:Double-Blind Method; D006801:Humans; D007779:Lactobacillus acidophilus / Q000502:physiology*; D010919:Placebos; D019936:Probiotics / Q000627:therapeutic use*; D014195:Travel
chemical_list: D010919:Placebos