In fact , participants with butyrate > 100 mmol/kg of wet feces had a mean butyrate reduction of 49 21 % and a concomitant decrease in the sum of 6 Clostridiales genera , namely Faecalibacterium , Blautia , Anaerostipes , Pseudobutyrivibrio , Clostridium , and Butyrivibrio ( P = 0.021 ) , after the probiotic intervention .