Inhibition of gut bacteria communication by Toyocerin®

By Marisol Castillo, DVM, PhD

Bacillus cereus var toyoi is an sporulated gram positive bacterium used in livestock nutrition as the active substance of the feed additive Toyocerin® EC no. E1701. Nowadays, it is authorised in all pig categories, broilers, turkeys, cattle for fattening and rabbits in the EU, and it is produced and sold by Rubinum SA.

Several trials have demonstrated the effect of Toyocerin® improving gut health by a direct and indirect attack to some of the most usual gut pathogenic bacteria in livestock. In this regard, and with the aim of going one step further, Rubinum SA have recently demonstrated that Toyocerin® not only inhibits the growth of E. coli, Salmonella and E. coli among other bacteria, but it also inhibits their communication and therefore their potential infection to the host (see Table 1).

In this regard, it is known that gut bacteria use signal molecules (N-acyl homoserine lactones; AHLs) to regulate gene expression , including virulence factors (eg. bacterial toxins, proteins involved in bacterial attachment),  in a population density-dependent manner, a process of communication referred to as quorum sensing (QS).

Hence, disruption of bacterial QS by degradation of AHLs has been proposed as a new anti-infective strategy to control bacterial infections. In several fields, blocking of QS by degradation of AHL molecules has been proposed as a promising alternative to diminish bacterial virulence, being up today, Toyocerin® the only probiotic marketed that have demonstrated this action. Toyocerin® has shown activity as a degrader of synthetic-AHLs and naturally produced AHLs being these results promising as well as helpful to explain the effect of Toyocerin® against pathogenic bacteria in animals gut.