| description |
Streptococcus pyogenes, is a Gram-positive bacterium that infects the upper respiratory tract, including the tonsils and pharynx, and is responsible for post-infection diseases such as rheumatic fever and glomerulonephritis. S. pyogenes also causes severe invasive diseases including necrotizing fasciitis and streptococcal toxic shock syndrome (STSS).Recently, we reported that a region encoding the SalR-SalK two component regulatory system and the adjacent type I restriction modification system was deleted in some emm 1 type isolates (APMIS, Volume 122, Issue 10, pages 914-921, DOI: 10.1111/apm.12230). The isolates with the deletion were detected only in the emm 1 strains that were isolated after 2010, but not before 2010. we named the emm 1 strains with the deletion as a "novel-type" emm 1 strain. In a experiment using mouse invasive infection model, both of two novel emm 1 type strains (10-85 and 11-171) isolated from "STSS" patients were more virulent than a novel emm 1 type strain (11O-2) isolated from a "non-STSS" patient. In the present project, we performed whole genome sequences of strains 10-85, 11-171, and 11O-2, and searched them for some specific mutations or single nucleotide polymorphisms (SNPs) existing in only low-virulent strain 11O-2, but not strains 10-85 and 11-171. |