Uncovering the mysteries of invasive streptococcal diseases.

Group A streptococci, although considered extracellular pathogens, are capable of causing severe life-threatening invasive infections, such as necrotising fasciitis, bacteraemia and toxic-shock-like syndrome. A complete understanding of the mechanism by which these organisms cause invasive disease has been hampered by the extreme human specificity and high genetic diversity among group A streptococci. Three recent papers have uncovered some of the mysteries of streptococcal invasive diseases. Using two different technologies, these papers have contributed enormously towards our understanding of the molecular events underlying streptococcal invasive diseases.