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Kikuchi Ken
Department School of Medicine(Tokyo Women's Medical University Hospital), School of Medicine Position Professor |
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| Article types | Original article |
| Language | English |
| Peer review | Peer reviewed |
| Title | A streptolysin S homologue is essential for β-haemolytic Streptococcus constellatus subsp. constellatus cytotoxicity. |
| Journal | Formal name：Microbiology (Reading, England) Abbreviation：Microbiology ISSN code：(1465-2080)1350-0872(Linking) |
| Domestic / Foregin | Foregin |
| Volume, Issue, Page | 160(Pt 5),pp.980-91 |
| Author and coauthor | Tabata Atsushi, Sato Yuji, Maya Kentaro, Nakano Kota, Kikuchi Ken, Whiley Robert A, Ohkura Kazuto, Tomoyasu Toshifumi, Nagamune Hideaki |
| Publication date | 2014/05 |
| Summary | Streptococcus constellatus is a member of the Anginosus group streptococci (AGS) and primarily inhabits the human oral cavity. S. constellatus is composed of three subspecies: S. constellatus subsp. constellatus (SCC), S. constellatus subsp. pharyngis and the newly described subspecies S. constellatus subsp. viborgensis. Although previous studies have established that SCC contains β-haemolytic strains, the factor(s) responsible for β-haemolysis in β-haemolytic SCC (β-SCC) has yet to be clarified. Recently, we discovered that a streptolysin S (SLS) homologue is the β-haemolytic factor of β-haemolytic Streptococcus anginosus subsp. anginosus (β-SAA), another member of the AGS. Furthermore, because previous studies have suggested that other AGS species, except for Streptococcus intermedius, do not possess a haemolysin(s) belonging to the family of cholesterol-dependent cytolysins, we hypothesized that, as with β-SAA, the SLS homologue is the β-haemolytic factor of β-SCC, and therefore aimed to investigate and characterize the haemolytic factor of β-SCC in the present study. PCR amplification revealed that all of the tested β-SCC strains were positive for the sagA homologue of SCC (sagA(SCC)). Further investigations using β-SCC strain W277 were conducted to elucidate the relationship between sagA(SCC) and β-haemolysis by constructing sagA(SCC) deletion mutants, which completely lost β-haemolytic activity. This loss of β-haemolytic activity was restored by trans-complementation of sagA(SCC). Furthermore, a co-cultivation assay established that the cytotoxicity of β-SCC was clearly dependent on the presence of sagA(SCC). These results demonstrate that sagA(SCC) is the factor responsible for β-SCC β-haemolysis and cytotoxicity. |
| DOI | 10.1099/mic.0.075580-0 |
| PMID | 24600025 |