Biological strategies expressed by different Streptococcus pyogenes strains: an explanation of the epidemiology

The numerous reports in the last ten years on the serious diseases caused by Streptococcus pyogenes indicate the continued significance of this pathogen. Furthermore, clinical studies and modern techniques have yielded new information on S. pyogenes and its pathogenic mechanisms. Although much still remains to be discovered about the biology of S. pyogenes, two different strategies--the 'epidemic' and the 'endemic' strategy--can be seen in the interaction of different S. pyogenes strains with the human host. The challenges posed by these two groups of bacteria are also outlined.