[Invasive Lancefield group A streptococcal infections in the Netherlands].

After a steady decrease in morbidity and mortality resulting from severe group A streptococcal (GAS) infections, the 1980s witnessed a resurgence of invasive GAS disease. As a result a nationwide laboratory-based surveillance for invasive GAS infections was conducted at the National Institute of Public Health (RIVM) from 1994 to 2003. The estimated annual incidence ranged from 2.0 to 4.0 cases per 100,000 individuals per year. The case-fatality rate was 18% overall but varied substantially depending on the manifestation of the disease. GAS infections may be complicated by toxic shock-like syndrome (TSS) which is caused by bacterial exotoxins. Case fatality among TSS cases was 59%. The M-protein that extends from the cell membrane is used for sub-typing GAS in > 150 different M-types. Increased intrinsic virulence has been reported in Streptococcus pyogenes of certain M-types, notably M1 and M3. In the Netherlands these M-types have been independently associated with fatality. Over the last 50 years the genome of these M-types appears to have become enriched with phage-encoded virulence factors, possibly contributing to the altered epidemiology of invasive GAS disease. Despite this genetic plasticity, GAS have remained uniformly susceptible to penicillin. In-vitro studies have shown that the administration of immunoglobulin G can have a neutralising effect in cases ofTSS but clinical studies have failed to provide any statistical support for this.