Clinical Question: Can lactobacillus preparations, given orally, vaginally, or both, prevent post-antibiotic vaginal candidiasis?

Setting: Outpatient (primary care)

Study Design: Randomized controlled trial (double-blinded)

Allocation: Concealed

Synopsis: Investigators evaluated the role of products containing Lactobacillus spp. to prevent vaginal candidiasis in 278 nonpregnant women who required a short course of antibiotics for a nongynecologic infection. The actual antibiotics were not specified. The women were assigned randomly, using concealed allocation, to receive an oral powder containing Lactobacillus spp., a vaginal pessary containing Lactobacillus, both treatments, or placebo. The women took the powder twice daily 20 minutes before meals and used one pessary at night for 10 nights during the six-day course of antibiotics and for four days after. Viability of the lactobacilli was confirmed. Candida was cultured in 23 percent of the women, a rate consistent with other research. The rate of vaginal candidiasis was similar in women receiving one or both forms of probiotic or placebo. The study ended early because of lack of benefit.

Bottom Line: Lactobacillus, given orally, vaginally, or both, has no effect on the development of culture-proven vaginal candidiasis. Lactobacillus probiotics are effective, however, in decreasing antibiotic-associated diarrhea (Cremonini F, et al. Meta-analysis: the effect of probiotic administration on antibiotic-associated diarrheoea. Aliment Pharmacol Ther August 2002;16:1461–7). (Level of Evidence: 1b)