The remedy for streptococcosis of pigs was found in the tonsils of healthy piglets

Streptococcus suis (S. suis) is a family of pathogenic Gram-positive bacterial strains. A multitude of pathogens accelerates the emergence and spread of antibiotic resistance in the bacterial community when such drugs are used consistently and in large quantities in suckling and weaned piglets.

PhD dissertation research by Isabela Fernandez de Oliveira, Wageningen University, focuses on the microbiota of the piglet tonsils as a source of natural bioactive compounds and candidate probiotics. She also investigated the role of the tonsils as an entry point for Streptococcus suis infection. Overall, her dissertation work focuses on the tonsil microbiota as a source of natural bioactive compounds and candidate probiotics to fight infections and ultimately lead to a decrease in antibiotic use .

“The first part of the work examined whether there is evidence of an intracellular stage of systemic infection in piglets with S. suis. Subsequently, the diversity and composition of the microbiota of the tonsils of healthy piglets was described and a search was made for bacteria capable of inhibiting the growth of S. suis in the laboratory due to natural antibiotic compounds. A number of commensal, that is, “friendly”, bacterial strains have also been selected as candidate probiotics based on their ubiquity in the tonsil microbiota of healthy piglets and (in the laboratory) on antagonism to disease-associated virulent S. suis strains. Moreover, the efficacy of a candidate probiotic has been established in a controlled farm experiment.

The conclusion is that the candidate probiotic can be used in a novel approach to reduce the problems caused by S. suis infectious diseases and counteract the spread of antibiotic resistance in the microbiota, including those microbiota where the relative abundance of S. suis is high. The results of the study helped to better understand the composition of the microbiota on the tonsils of healthy piglets, what natural antibiotics are produced in biofilms on the tonsils, as well as the possibility of containing infectious diseases by natural antagonistic bacterial strains,” the scientist writes.