Absence of efficacy of nonviable Lactobacillus acidophilus for the prevention of traveler's diarrhea: a randomized, double-blind, controlled study.
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.
Briand
Valérie
V
Emerging Diseases Epidemiology Unit, Institut Pasteur, Paris, France. vale.briand@laposte.net
Buffet
Pierre
P
Genty
Sabine
S
Lacombe
Karine
K
Godineau
Nadine
N
Salomon
Jérome
J
Vandemelbrouck
Eric
E
Ralaimazava
Pascal
P
Goujon
Catherine
C
Matheron
Sophie
S
Fontanet
Arnaud
A
Bouchaud
Olivier
O
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
D010919:Placebos