Abstract
Primary peritonitis caused by Group A β-haemolytic streptococci (GAS) is extremely rare and is usually only seen in the presence of underlying disease. This report describes the case of a previously fit young woman who developed primary GAS peritonitis. She had a laparotomy performed at which large amounts of intra-peritoneal pus was identified but no focus of infection was found. Broad spectrum antibiotics were initially used, these were changed to intravenous benzylpenicillin when GAS was isolated. She made a good recovery and was discharged 2 weeks after admission on oral amoxycillin. The organism was serotyped as T3/M3/R3 (opacity factor negative) and it is interesting that the same serotype was isolated from a throat swab taken from her daughter. We also discuss the possible routes of infection and the epidemiology of invasive GAS disease.