Abstract

The beta-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. A case is reported of 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.