INVASIVE GROUP-A STREPTOCOCCAL INFECTIONS IN NORTH-CAROLINA - EPIDEMIOLOGY, CLINICAL-FEATURES, AND GENETIC AND SEROTYPE ANALYSIS OF CAUSATIVE ORGANISMS

During 1994 and 1995, an increase in the number and severity of group A streptococcal (GAS) infections was noted in North Carolina. Ninety-s ix patients had GAS recovered from blood and other sterile body fluids , abscesses, and soft tissue. The overall case fatality rate was 11% b ut was much higher in patients with toxic shock syndrome (55%) and nec rotizing fasciitis (58%). Recent invasive GAS isolates were compared w ith pre-1994 invasive isolates and temporally related pharyngeal isola tes by M protein serotyping, pulsed field gel electrophoresis (PFGE), and polymerase chain reaction amplification of the streptococcal pyrog enic exotoxin A gene. Serotypes M1 and M3 accounted for 50% of recent invasive isolates (1994-1995) and 58% of pharyngeal isolates (1994). T he latter isolates demonstrated PFGE patterns that were identical to i nvasive M1 and M3 strains, suggesting that pharyngeal infections may h ave served as a reservoir for virulent GAS clones.