Saccharomyces boulardii was shown to be capable of inhibiting multiplication of enteropathogenic bacteria in vitro and is currently used for its anti-diarrhoea properties. We studied the capacity of this yeast to antagonize Salmonella typhimurium and Shigella flexneri in the intestinal tract of conventional or gnotobiotic NMRI mice. Conventional animals were given daily 10 mg doses of S. boulardii, whereas germ-free animals were given a single 10 mg dose. Both groups were challenged orally 5 d later with the pathogenic bacteria (10(8) or 10(2) viable cells, respectively). Control groups were treated with saline instead of S. boulardii. Mortality and/or histopathological data showed a protective effect against the pathogenic bacteria in yeast-treated mice. Saccharomyces boulardii colonized the digestive tract of gnotobiotic mice and the number of viable cells ranged around 10(10) g-1 of faeces. In experimental and control gnotobiotic animals, Salm. typhimurium and Sh. flexneri became rapidly established at a level of about 10(10) viable cells g-1 of faeces and remained at high levels until the animals died or were sacrificed. The protection against Salm. typhimurium and Sh. flexneri obtained in conventional and/or gnotobiotic mice previously associated with S. boulardii is not due to the reduction of the bacterial populations in the intestines.

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As is the case for Saccharomyces boulardii, Saccharomyces cerevisiae W303 protects Fisher rats against cholera toxin (CT). The addition of glucose or dinitrophenol to cells of S. boulardii grown on a nonfermentable carbon source activated trehalase in a manner similar to that observed for S. cerevisiae. The addition of CT to the same cells also resulted in trehalase activation. Experiments performed separately on the A and B subunits of CT showed that both are necessary for activation. Similarly, the addition of CT but not of its separate subunits led to a cyclic AMP (cAMP) signal in both S. boulardii and S. cerevisiae. These data suggest that trehalase stimulation by CT probably occurred through the cAMP-mediated protein phosphorylation cascade. The requirement of CT subunit B for both the cAMP signal and trehalase activation indicates the presence of a specific receptor on the yeasts able to bind to the toxin, a situation similar to that observed for mammalian cells. This hypothesis was reinforced by experiments with 125I-labeled CT showing specific binding of the toxin to yeast cells. The adhesion of CT to a receptor on the yeast surface through the B subunit and internalization of the A subunit (necessary for the cAMP signal and trehalase activation) could be one more mechanism explaining protection against the toxin observed for rats treated with yeasts.

Renal histological features of focal segmental glomerulosclerosis (FSGS) are found in 75% of pediatric patients with steroid-resistant nephrotic syndrome. In order to evaluate the predictive factors of chronic kidney disease (CKD), we retrospectively reviewed the records of 110 children with biopsy-proven FSGS admitted between 1972 and 2004. Renal survival was analyzed by the Kaplan-Meier method and Cox's regression model. Two multivariate models were developed: (1) from the onset of symptoms to the occurrence of CKD and (2) from the time of renal biopsy to CKD. Mean follow-up time was 10 years [standard deviation ((SD) 5.5], and 24 patients (21.8%) progressed to CKD. At baseline, after adjustment three variables remained as independent predictors of CKD: age >6.5 years (RR=3.3, 95% CI=1.3-7.8), creatinine >1 mg/dl (RR=2.5, 95% CI=0.97-6.5), and non-response to steroids (RR=7.3, 95% CI=2.7-19.7). In a model with continuous variables only age and non-response to steroids were associated with CKD. At the time of renal biopsy, after adjustment two variables remained as independent predictors of CKD: hematuria (RR=3.0, 95% CI=1.2-7.3) and creatinine >0.8 mg/dl (RR=4.3, 95% CI=1.7-10.6). In a model with continuous variables four factors predicted CKD: age, creatinine, hematuria, and percentage of global sclerosis.