Streptococcus suis infection: An emerging/reemerging challenge of bacterial infectious diseases?

Feng, Youjun; Zhang, Huimin; Wu, Zuowei; Wang, Shihua; Cao, Min; Hu, Dan; Wang, Changjun

The clinical consequence of S. suis infection is determined by the complicated interplay between this zoonotic pathogen and its host. A series of bacterial components as well as a collection of host cell factors contribute to this pathogenesis-related process. So far, almost 60 bacterial components have been identified to be involved in the infection and/or pathogenicity of S. suis ( Table 2) . Of particular note, Wilson and coworkers 100 developed a powerful signature-tagged mutagenesis (STM) system for S. suis and identified nearly 20 potential virulence associate elements through screening the library consisting of approximately 2600 mutants ( Table 2) . However, exact roles of these genes needed further verification. According to their general roles in the context of bacterial life cycles, these bacterial virulence-associated factors were temporarily classified into the following three sub-groups (of note some genes probably can be attributed to two different classifications due to their dual characteristics): (1) surface/secreted elements; (2) enzymes/proteases; (3) transcription factors/regulatory systems; and (4) others (transporters/secretion systems) ( Table 2) .