Probiotic prevents diarrheaa

The American Journal of Gastroenterology study was performed on 255 hospital patients, ages 50 to 70, receiving penicillin, cephalosporin or clindamycin. Within 36 hours of starting antibiotic therapy, patients began to take (each day, 2 hours after breakfast) either 2 probiotic capsules, 1 probiotic capsule and 1 placebo capsule, or 2 placebo capsules. All patients were hospitalized for at least 5 days and received antibiotics for at least 3 days (but not more than 14 days). They continued with their assigned treatment for 5 days after finishing the course of antibiotics. Each probiotic capsule contained 50 billion colony-forming units of L acidophilus and L. casei.

At 21 days after the end of their assigned treatments, the incidence of antibiotic-associated diarrhea was 44.1% in the placebo group, 28.2% in the 1-capsule group and 15.5% in the 2-capsule group. Rates of diarrhea due to C. difficile were 23.8%, 9.4%, and 1.2% with placebo, 1 capsule, and 2 capsules, respectively.

The authors estimate that treating five patients at the higher probiotic dose would prevent one case of C. difficile-associated diarrhea. Overall, the 2-capsule group had the lowest rate of gastrointestinal symptoms, followed by the 1-capsule group. The investigators observed a similar pattern for symptom duration. They attribute their high response rates to the high probiotic dosage: "The probiotic load of this quantity likely overwhelms the intestinal tract and repopulates the gut with nonpathogenic flora, as well as enhances immune response to inhibit or destroy pathogenic bacteria."