Saccharomyces cerevisiae fungemia: an adverse effect of Saccharomyces boulardii probiotic administration.

A probiotic can be defined as a live, non-pathogenic microbial supplement that exerts a positive influence on the health or physiology of the host [1, 2]. Probiotics consist of either bacteria, especially lactic acid bacteria, or yeast. Probiotics have mainly been used for gastrointestinal and vaginal diseases [3]. The effects of probiotics are thought to be related to direct enzymatic effects or to a modulation of the endogenous flora or of the immune system [4]. Efficacy of pro-biotics in persons with enzymatic defects is now well accepted. Lactase from lactic acid–producing bacteria contained in yogurt helps to digest lactose in subjects with lactose intolerance and in those with short-bowel syndrome [1]. Saccharomyces cerevisiae expresses significant sucrase and some isomaltase activity but no lactase activity , and it has been proposed to improve malabsorption in patients with sucrase-isomaltase deficiency who intentionally or unintentionally consume sucrose [5]. Antibiotic-induced microbial imbalance is a common cause of diarrhea and, in severe cases, of pseudomembranous co-litis. Attempts have been made to determine whether the administration of probiotics would prevent or treat antibiotic associated diarrhea. Several ran-domized trials successfully demonstrated a reduced risk of antibiotic-associated diarrhea when Lactobacillus acidophilus plus Lactobacillus bulgaricus, Lactobacillus rhamnosum GG, Enterococcus faecium SF68 (a lactic acid–producing strain), Bi-fidobacterium longum (with or without Lactobacillus species), or Saccharomyces boulardii were administered concomi-tantly with the antibiotic [1]. A meta-analysis was recently conducted by D'Souza et al. [2] to evaluate the efficacy of probiotics for prevention and treatment of antibiotic-associated diarrhea. Nine double-blind, placebo-controlled trials were relevant for this analysis. Four of the trials used S. boulardii, and 5 used lactobacilli or E. faecium SF68. The OR for the pooled data from the 9 studies (0.37; 95% CI, 0.26–0.52) was in favor of active treatment over placebo for the prevention of antibiotic-associated diarrhea. In a separate analysis, the yeast and the nonyeast trials showed a similar beneficial effect (OR, 0.39 and 0.34, respectively ; 95% CI, 0.25–0.62 and 0.19–0.61, respectively). In addition to these studies, a double-blind, randomized, placebo-controlled study of 124 patients also demonstrated that the combination of antibiotics (van-comycin and/or metronidazole) and S. boulardii more efficaciously prevented the recurrence of Clostridium difficile–associ-ated diseases than did antibiotics plus placebo (26% vs. 45%) [6]. A follow-up study performed to standardize the dose and duration of antimicrobial therapy showed that the combination of S. boulardii and high-dose vancomycin (2 g/day) reduced the frequency of recurrences, but …