Purpose The clinical relevance of M1 UK type strains of Streptococcus pyogenes in Japan remains insufficiently defined. We investigated the molecular epidemiology of M1 UK type strains and evaluated their clinical associations among adults with invasive group A Streptococcus (iGAS) infections. Methods We conducted a nationwide multicenter surveillance study of iGAS infections from December 2023 to March 2025. Molecular typing,...

Purpose The incidence of invasive Streptococcus dysgalactiae subsp. equisimilis (iSDSE) infections is increasing in developed countries, but studies on the risk factors for death in iSDSE infections are scant. Here, we aimed to clarify risk factors and predictors of mortality in adults with iSDSE infections. Methods A multicentre observational study of adults with iSDSE infections was conducted to investigate the effects of ho...

Summary Since Robert Koch and colleagues found agar to be an effective gelling agent over a century ago, the pure culture method using agar plates has long been a standard of microbiology. Agar is undoubtedly easy to handle and useful for culture of microorganisms, but recent discovery of the ubiquity of microorganisms that cannot be cultured on agar raises a question: is agar really the best agent? In this study, we investiga...