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Toxin‐Gene Profile Heterogeneity among Endemic Invasive European Group A Streptococcal Isolates

2003; Oxford University Press; Volume: 188; Issue: 10 Linguagem: Inglês

10.1086/379230

1537-6613

Franz‐Josef Schmitz, Andreas Beyer, Emmanuelle Charpentier, Birgitta Henriques Normark, Marc Schade, Ad C. Fluit, D. Häfner, Rodger Novak,

Bacterial Identification and Susceptibility Testing

We determined the toxin-gene profiles of 239 endemic, invasive group A streptococcal (GAS) isolates that circulated, within a 5-year period, in European university hospitals. Profiling was performed by use of multiplex polymerase chain reaction that screened for 9 streptococcal pyrogenic exotoxins (speA, speB, speC, speF, speG, speH, speJ, ssa, and smeZ). Analysis revealed that invasive GAS isolates do not share a common toxin-gene profile. Although all emm types were characterized by several different toxin-gene profiles, a predominance of 1 or 2 toxin-gene profiles could be observed, reflecting that a few invasive clones have spread successfully throughout the world. Remarkably, statistical pair-wise analysis of individual toxin genes revealed that strains that did not share the predominant profile still showed a nonrandom distribution of key toxin genes characteristic of the specific emm type. This could indicate that M proteins function, directly or indirectly, as barriers for horizontal gene exchange.