MOLECULAR, SEROLOGICAL, AND CLINICAL-FEATURES OF 16 CONSECUTIVE CASESOF INVASIVE STREPTOCOCCAL DISEASE

We performed a comprehensive analysis of the molecular, serological, a nd clinical features of 16 consecutive cases of invasive streptococcal disease (ISD), The majority of cases were linked to two group A strep tococcus (GAS) clones closely related by pulsed-field gel electrophore sis (PFGE) and designated as PFGE-1 and PFGE-1.1. These clones, seroty ped as M-3, T-3/B3264, carried an allelic variant of the gene that enc odes pyrogenic exotoxin A (speA3) and the gene that encodes streptococ cal superantigen (SSA) but different emm alleles that encode M-protein . The characteristics and clinical features of patients were similar t o those described in previous reports, regardless of the responsible G AS clone. However, worse clinical outcomes (shock and death) were more frequent when patients infected with PFGE1/1.1 clones were considered as a group and compared with all other patients as a group. One strik ing feature in some patients with deep tissue infection was a lack of inflammatory cells despite the presence of numerous streptococci. An e valuation of PFGE profiles of GAS isolated elsewhere demonstrated that the PFGE-1 clone has caused invasive disease in other locations in th e United States and in Japan.