Streptococcal toxic shock syndrome in North Queensland-a case controlled review of clinical and molecular determinants

Streptococcal toxic shock syndrome (STSS) is an uncommon but important complication of invasive group A streptococcal (GAS) disease. A number of clinical risk factors and molecular markers have been linked with STSS. We report here a case controlled review looking specifically at cases of STSS from North Queensland, between 1996 and 2005. All isolates obtained were cultured from sterile sites. Of these, there were 25 cases which fulfilled the criteria for STSS. These were matched for age, sex and ethnicity with 31 cases of invasive GAS without STSS. Indigenous patients represented 16% of the group. Mortality was significantly higher (28%) in the STSS group. Necrotising fasciitis and an elevated serum creatinine on admission were significantly associated with STSS. There was no significant difference in the presence of risk factors or mean total white cell count in both groups. There was also no significant difference in the presence of streptococcal pyrogenic exotoxins a, c, g, h and ssa, prtF1, mean internalization efficiency, biotypes or emm types, in isolates involved. Although not statistically significant, there was a trend for prtF2 to be associated with STSS.