Alkalihalobacillus clausii bacteremia after probiotic use for acute diarrhea: a case report.

Alkalihalobacillus clausii (previously known as Bacillus clausii) is a spore-forming bacterium used as a probiotic due to its resistance to gastric acidity and intestinal conditions. It is marketed for managing acute diarrhea, though evidence of its efficacy and safety is limited. We present the case of an 87-year-old man with acute viral diarrhea treated with Alkalihalobacillus clausii, who developed septic shock with blood cultures confirming Alkalihalobacillus clausii bacteremia. Intensive care and daptomycin therapy led to clinical resolution.