The Products of Probiotic Bacteria with Potential for Improving Human Health.

Colin HILL

APC Microbiome Institute, University College Cork, Ireland

Probiotics are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.  However, these living organisms can only interact with the host through the production of cell wall structures, enzymes, antimicrobials, metabolites and even ‘macromolecular products’ such as bacteriophage.  All biological interactions between probiotic and host are mediated by these suites of products, possibly or perhaps even probably acting in concert to elicit complex effects on the host physiology.  Understanding these interactions is the very basis of understanding probiotic mechanisms, but they are complex and difficult to unravel.  One goal of probiotic science is to describe a set of probiotic factors similar to those virulence factors identified in pathogenic microbes, while accepting that the concept of ‘one microbial product, one health benefit’ is likely to be overly simplistic. 

This talk will cover several examples where a particular probiotic product has been linked to a specific health benefit, at least in pre-clinical models.  These include the production of bacteriocins, enzymatic products such as bile salt hydrolases or enzymes which can convert linoleic acid into conjugated forms, metabolites such as GABA, and cell wall or pili structures which can interact with the host immune system.  Identifying molecules/products such as these will allow for more detailed health claims, better selection of the correct probiotic for the correct health state, and perhaps the development of improved next generation probiotics with enhanced health benefits.