Infectious diseases remain a significant problem in the healthy breeding of swine. It has always been the focus of attention. No doubt, there are many pigs dying from infectious diseases every year. This high mortality rate has raised particular attention from the scientists, government and enterprises. They have made great efforts in their own aspects to control the infectious diseases in healthy breeding of swine. In fact, important advances that have been made in the study of Streptococcus suis type 2 (SS2) give some light on controlling infectious diseases.

Streptococcus suis is an important and prevalent swine pathogen and is also considered an important zoonotic agent. Two large outbreaks of SS2 in China were associated with clinical manifestations of toxic shock syndrome and high lethality. Research during the last ten years has identified many virulence-associated factors, such as suilysin, SrtA, PgdA, SodA, CcpA, the two-component signal transduction system SalK-SalR and the Rgg transcriptional regulator. However, little is known about the underlying mechanisms of SS2 pathogenicity.

Using a gene knockout Method, a team of researchers from the Institute of Subtropical Agriculture, Chinese Academy of Sciences (ISA), and Zhejiang University, isolated SS2 strain JX081101 (ST7) from the lung of a diseased pig to study the Streptococcus suis type 2 in controlling pigs’ infectious diseases.

The researchers found that a gene termed beta-galactosidase plays an important role in bacterial adhesion and host pathology. Deleting SSU0587 resulted in decreased adhesion of SS2 to endothelial cells and reduced pathogen loads in the brains of infected mice. However, deleting SSU0587 had no measurable impact on SS2 invasion or on mouse survival after intraperitoneal inoculation with SS2.

This work was funded by the Chinese Ministry of Agriculture (project No. 200803016).

The study entitled “Streptococcus suis Type 2 SSU0587 Protein is a Beta-Galactosidase That Contributes to Bacterial Adhesion but Not to Virulence in Mice” has been published in Volume 76, Issue 7, March 2014 of Journal of Veterinary Medical Science, details could be found at http://dx.doi.org/10.1292/jvms.13-0625.