Trend of Respiratory Tract-Associated Streptococcus dysgalactiae Subsp. Equisimilius at General Japanese Hospital from 2013 to 2015

Streptococcus dysgalactiae subsp. equisimilius are pathogenic bacteria which cause various infectious diseases from acute pharyngitis to streptococcal toxic shock syndrome. Although Streptococcus dysgalactiae subsp. equisimilius infection has been increasing recently, the recent characteristic investigation of respiratory tract associated Streptococcus dysgalactiae subsp. equisimilius has not been performed in Japan. In this study, we analyzed the relationship between respiratory tract and norespiratory tract associated Streptococcus dysgalactiae subsp. equisimilius by investigating the recent clinical characteristics and antimicrobial susceptible patterns of 98Streptococcus dysgalactiae subsp. equisimilius isolated during 2013-2015 in Japan. There was significant difference of gender between respiratory tract and no respiratory tract associated Streptococcus dysgalactiae subsp. equisimilius. No Streptococcus dysgalactiae subsp. equisimilius from no respiratory tract were found under 18 years-old patients. The prevalence of clindamycin non susceptible Streptococcus dysgalactiae subsp. equisimilius isolates from respiratory tract was significant greater than those from non-respiratory tract. We also analyzed the relationship between respiratory tract associated Streptococcus dysgalactiae subsp. equisimilius and Streptococcus pyogenes in 2014.There was no significant difference of gender between Streptococcus dysgalactiae subsp. equisimilius and Streptococcus pyogenes. The numbers of Streptococcus pyogenes-infected patients were significantly greater than those of Streptococcus dysgalactiae subsp. equisimilius-infected patients in children from 1 to 18 years old. From antimicrobial resistance, we found that the numbers of clarithromycin resistant Streptococcus pyogenes were greater than those of clarithromycin resistant Streptococcus dysgalactiae subsp. equisimilius among respiratory tract isolation. Our results suggest that the clinical and antimicrobial susceptible patterns are useful for screening the respiratory tract associated Streptococcus dysgalactiae subsp. equisimilius infection.