Quantitative and qualitative characterization of commercially available oral suspension of probiotic products containing Bacillus Clausii spores

Probiotics contain beneficial live bacteria that confer several health benefits to the host. For the past 50 years, spore-forming Bacillus species have been used in the form of probiotics. Among these, Bacillus clausii strains are used for the management of acute and antibiotic-associated diarrhoea. In the present work, we have evaluated the asserted label information on randomly chosen commercial Bacillus clausii spore suspension of probiotic products. The quality and number of viable bacteria were evaluated based on the colony count, antibiotic resistance, and hemolytic activity assays. The colony fingerprinting and 16S rRNA gene-sequencing techniques were used to confirm the presence of a univariate strain (Bacillus clausii). Our results corroborated the label count of 2 × 10(9) CFU/5 mL in BACIPRO®, ENTEROGERMINA®, and TUFPRO® products. However, vegetative spore count was not found to match with the given label count in BENEGUT®, PROALANA-B®, β-LOCK®, and PROCILLUS® Bacillus clausii brands. In the hemolytic activity assay, except for β-LOCK®, the other 6 products showed gamma-hemolysis activity. Bacillus clausii isolated from all 7 probiotic products demonstrated resistance to several broad-spectrum antibiotics. The 16S rRNA gene-sequencing data detected genera of Bacillus and Bacillus clausii strain in the BACIPRO®, ENTEROGERMINA®, PROALANA-B®, BENEGUT®, and TUFPRO® products; however, Ralstonia mannitolilytica and Paenibacillus dendritiformis species were identified in β-LOCK® and PROCILLUS®, respectively. As correct label information was observed only in BACIPRO®, ENTEROGERMINA®, and TUFPRO® products, it is proposed that a more stringent quality check would minimize the possibility of mismatch concerning the label information. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12866-022-02631-w.