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Lactobacillus Does Not Prevent Post-Antibiotic Yeast Infections

In fact, results from this small study suggest the potential for harm.

To avoid developing vulvovaginal candidiasis after antibiotic use, many women use complementary and alternative therapies, including lactobacillus in various forms (e.g., oral capsules, vaginal suppositories, yogurt). In this Australian study, 278 women (age range, 18-50) with nongynecologic infections were randomized to receive one of four regimens during 6 days of antibiotic use and 4 days thereafter: an oral lactobacillus-containing powder (one-half teaspoon twice daily) and a lactobacillus-containing vaginal suppository (once daily at bedtime); oral lactobacillus and vaginal placebo; vaginal lactobacillus and oral placebo; or double placebo.

Women completed symptom surveys and provided self-collected vaginal-swab specimens at baseline and either 4 days after completing their randomized treatment or when symptoms developed. Cases were defined as women with symptoms plus candida isolated from the follow-up swab; asymptomatic women with positive cultures were not considered cases.

The trial was terminated when enrollment was 62% complete because interim analysis showed no evidence of treatment benefit. Of the 235 women with complete outcome data (85% of those randomized), 55 developed symptomatic vaginal candidiasis. The incidence was 24% with oral and vaginal lactobacillus, 24% with oral lactobacillus and vaginal placebo, 29% with vaginal lactobacillus and oral placebo, and 17% with double placebo. The resulting odds ratios for developing candidiasis were 1.06 for oral lactobacillus and 1.38 for vaginal lactobacillus (both ORs were nonsignificant).

Comment: Despite conventional wisdom encouraging women to use lactobacillus preparations to prevent yeast infections after antibiotic use, this small but well-designed study demonstrated no benefit from this practice. In fact, the findings suggest the potential for harm. Based on this study, clinicians should discourage patients from using these products to prevent post-antibiotic yeast infections. At the time of publication, the original article was available free of charge.

— Jane E. Corboy, MD

Published in Journal Watch Women's Health November 3, 2004

Citation(s):

Pirotta M et al. Effect of lactobacillus in preventing post-antibiotic vulvovaginal candidiasis: A randomised controlled trial. BMJ 2004 Sep 4; 329:548-51.

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