RESUMO
Growing evidences suggest that Saccharomyces boulardii (SB) is efficacious against bacterial infections and inflammatory bowel diseases. This study investigated the effects of treatment with SB provided in a murine model of typhoid fever. Mice were divided into two groups: (1) control animals challenged with Salmonella Typhimurium (ST), and (2) animals receiving SB, and then challenged with ST. At days 0, 1, 5, 10 and 15 post-challenge, animals were euthanized and tissues collected to analyze bacterial translocation, cytokines, signaling pathways and histological analysis. Survival rate and animal weight were also evaluated. Treatment with SB increased survival rate and inhibited translocation of bacteria after ST challenge. Histological data showed that SB also protected mice against liver damage induced by ST. SB decreased levels of inflammatory cytokines and activation of mitogen-activated protein kinases (p38, JNK and ERK1/2), phospho-IκB, p65-RelA, phospho-jun and c-fos in the colon, signal pathways involved in the activation of inflammation induced by ST. Further experiments revealed that probiotic effects were due, at least in part, to the binding of ST to the yeast. Such binding diminishes ST translocation, resulting in decreased activation of signaling pathways which lead to intestinal inflammation in a murine model of typhoid fever.
Assuntos
Translocação Bacteriana/imunologia , Febre Paratifoide/imunologia , Saccharomyces/imunologia , Salmonella typhimurium/imunologia , Animais , Citocinas/metabolismo , Modelos Animais de Doenças , Histocitoquímica , Fígado/imunologia , Fígado/microbiologia , Fígado/patologia , Camundongos , Análise de SobrevidaRESUMO
In randomized, controlled field trials in Area Norte and Area Occidente of Santiago, Chile, 2 (Norte) or 3 (Occidente) doses of live oral typhoid vaccine Ty21a in enteric-coated capsules conferred protection against confirmed Salmonella enterica serovar Typhi disease (53% efficacy in Norte; 67% efficacy in Occidente) during 3 years of follow-up. There was also a trend in each trial showing protection against S. enterica serovar Paratyphi B disease (56% efficacy in Norte; 42% efficacy in Occidente). To enhance statistical power, an analysis was performed using pooled data from the 2 trials; this pooling of data was justified by the following facts: epidemiologic surveillance and microbiological methods were identical, the trials overlapped during 22 of the 36 months of follow-up in each trial, the estimates of efficacy against paratyphoid B fever in the 2 trials were roughly similar, and the ratio of follow-up of vaccine recipients to control subjects in both trials was ~1 : 1. In the pooled analysis, Ty21a conferred significant protection against paratyphoid B fever (efficacy, 49%; 95% confidence interval, 8%-73%; P=.019).