A water-based probiotic supplement shows antipathogenic activity against Clostridium perfringens, Klebsiella pneumoniae, and Listeria monocytogenes

The antimicrobial potential of the water-based probiotic Symprove® against three clinically relevant pathogens, Clostridium perfringens, Klebsiella pneumoniae and Listeria monocytogenes, was investigated in vitro. Isothermal calorimetry and classical microbiological techniques were used to give an evaluation of Symprove's antimicrobial efficacy and mechanism of action against the pathogens. In mixed culture, the pathogenic species initially exhibited faster growth than the probiotic bacteria in Symprove, but the final bacterial counts revealed a significant reduction in pathogen viability compared with controls. After 48 h of co-incubation, more than a 3-fold log reduction in colony-forming unit (CFU) growth was observed for all three pathogens evaluated, demonstrating a strong inhibitory effect (in particular, levels of C. perfringens and K. pneumoniae declined to zero). The mechanism of inhibition appears largely pH-dependent, driven by production of lactic acid from the probiotic strains. These findings support and expand previous work showing that Symprove exerts antipathogenic effects against common organisms that cause infectious diseases and suggest a potential role for Symprove as an adjuvant therapy in infectious diseases.