Molecular epidemiology of group A streptococcal infection in the Northern Territory of Australia.

Abstract

Group A streptococcal infections and the non-suppurative sequelae are endemic among the Aboriginal population of Northern Australia6. Epidemics of acute glomerulonephritis have been noted5. Acute rheumatic fever rates of 651 per 100,000 population and point prevalence of 9.6 per 1000 for rheumatic heart disease have been reported recently2. A major hurdle in associating strains of group A streptococci with disease is poor discriminatory result of traditional M typing of the Northern Territory isolates7. Furthermore, as typing sera raised against more than one reference strain often reacted with a single local isolate, the typing results are ambiguous8. To overcome the limitations of M typing, we developed a universally applicable molecular typing method known as Vir-typing3. Vir-typing is based on the long-polymerase chain reaction (long-PCR) targeting the highly polymorphic virulence regulon of the group A streptococcal genome, using a set of universal primers. Vir-typing is simple, reproducible, amenable to be performed on a large number of samples, highly discriminatory and universally applicable to all group A streptococcal isolates, and provides unambiguous results3. We recently reported4 the Vir-typing results of 407 community isolates. In this communication, we extend these studies to the hospital isolates.