Microbiology Editor’s Choice: Understanding Streptococcus suis pathogenesis

Posted on February 1, 2019   by Microbiology Society

Each month, a manuscript published in our flagship journal Microbiology is chosen by a member of the Editorial Board. This month, the paper is ‘The Streptococcus suis sortases SrtB and SrtF are essential for disease in pigs’ and was chosen by Christiane Dahl.


Streptococcus suis is an important pig pathogen that causes severe economic problems in agricultural industry worldwide. Moreover, it is an emerging zoonotic agent that can cause infections in people in close contact with pork-derived products or infected pigs.

In Gram-positive bacteria, enzymes called sortases are used to attach specific proteins containing cell wall sorting signals to the cell surface. These surface proteins can play an important role in hostpathogen interactions. While the role of housekeeping sortase SrtA has been studied in in S. suis in detail, knowledge about secondary sortases like SrtC and SrtF was previously scarce.

The authors have closed this gap and have shown conclusively that these enzymes play an important role for invasion of the respiratory tract of pigs, thus contributing significantly to our knowledge of S. suis pathogenesis and highlighting possible new routes of generating immune responses that may be useful in protection against S. suis infections.


The Streptococcos suis sortases SrtB and SrtF are essential for disease in pigs

Streptococcus suis causes septicaemia, meningitis and death in pigs, but can also infect humans. We characterise three sortase surface proteins and show that they are essential for virulence in the host pig species. We also report a method to construct markerless in-frame deletion mutants in S. suis, a bacterium traditionally difficult to mutate. The unmarked sortase mutants are highly attenuated and may be suitable as low-cost vaccines to protect against S. suis infection. Apart from protecting pigs against disease and the associated economic prosperity, vaccines against S. suis will directly benefit human health and reduce the likelihood of antibiotics being given to animals.

To access the full paper, click here. Editor's Choice articles published in Microbiology are free to read.