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.

Case report

A morbidly obese woman in her 80s was admitted with a 1-week history of a productive cough and breathlessness. Her past history included type II diabetes mellitus, hypertension and chronic leg ulcers. On examination, she was pyrexial (39°C), pulse was 120/min and respiratory rate 26/min. Blood pressure was 95/45 mm Hg. There was no evidence of cellulitis, and no murmurs were …