Molecular typing ofStreptococcus pyogenesfrom remote Aboriginal communities where rheumatic fever is common and pyoderma is the predominant streptococcal infection

Abstract

SUMMARYAboriginal Australians in remote communities have high rates of rheumatic heart disease (RHD); yet pharyngitis is reportedly rare whilst pyoderma is common. Some strains of group A streptococci (GAS) have preference for the throat and others for the skin depending on M protein type. A study in three remote communities provided 350 GAS isolates foremmsequence typing, 244 were alsoemmpattern typed. There was 100% correlation betweenemmsequence and pattern type. Patterns D and E (non-throat tropic) made up 71% of throat and 87% of skin isolates although patterns A–C (throat tropic) were more common in the throat than the skin (RR 2·3, 95% CI 1·4–3·8) whilst the opposite was found for pattern D (RR 2·2, 95% CI 1·7–3·0). Pattern E favoured the throat (RR 1·4, 95% CI 1·1–1·8). Where environmental factors predispose to skin infection,emmpattern types D and E prevail, whatever the recovery site.