Fatal case of sepsis caused by a non-haemolytic strain of Streptococcus pyogenes

摘要

The β-haemolytic phenotype of Streptococcus pyogenes on blood media, which is due to the liberation of streptolysin S, is critical to the recognition of this pathogen in the diagnostic laboratory. We report the isolation of a non-haemolytic variant of S pyogenes from a blood culture that was taken from a patient who died of sepsis. Non-haemolytic isolates of S pyogenes are uncommon, very rarely associated with bacteraemia or sepsis, and may be difficult to recognise, especially if isolated from non-sterile sites.