Characterising Group A Streptococcus (Strep A) colonisation in children with a high risk of skin and throat infections

Remote living Indigenous Australian children have the highest recorded rates of skin sores in the world and are also at high risk of acute rheumatic fever (ARF) and rheumatic heart disease (RHD); almost all ARF cases diagnosed in Australia are Indigenous children living in remote areas. A comprehensive understanding of the burden and molecular diversity of Strep A skin sores and sore throats in children at the highest risk of developing ARF is needed to inform policy, advocacy and guidelines for primary prevention of ARF. The success of future interventions depends on this high-quality epidemiological data. Strep A carriage is a crucially needed component of epidemiological data and is necessary to understand Strep A transmission and biology. Available knowledge and tools to understand Strep A carriage are limited. Consequently, our ability to define and measure Strep A epidemiology for vaccine and surveillance studies is poor. This project directly addresses this knowledge gap.

The Missing Piece Surveillance Study (MPSS) is currently the only Australian study that aims to comprehensively understand the relative prevalence of skin sores and sore throats in remote Kimberley schools, where children are at high risk of developing ARF. The MPSS collects samples from two remote schools, and all consented children are screened three times per year, with weekly surveillance of those with sore throats for the remainder of the year. Crucially, samples collected in MPSS enable me to examine and apply molecular techniques to deliver high-quality Strep A surveillance and carriage data. This data will educate us on the prevalence of Strep A strains causing disease and facilitate vaccine development and other prevention measures.

Streptococcus pyogenes (Strep A) is a germ that causes sore throats and skin sores. Strep A can be passed from person to person during coughing, sneezing and close contact. Strep A can live in the throats of many people without causing serious problems. However, for some kids a sore throat or skin sore causes a reaction to Strep A that can damage their heart. This is known as Acute Rheumatic Fever (ARF) and is most likely to happen when Strep A is not treated. Subsequent episodes of ARF can lead to chronic damage to the heart, called Rheumatic Heart Disease. There is no cure for RHD and it is important to prevent it from occurring. We need accurate tests that can rapidly identify which skin sores and sore throats are caused by Strep A and therefore need antibiotic treatment to prevent RHD.

This project will determine which tests are the best ones to use to diagnose Strep A skin sores and sore throats. We will use cotton tip swabs to test skin and throat samples collected from children living in the Kimberley and involved in ongoing surveillance studies led by the Telethon Kids Institute. I will then detect which Strep A types are present in children at highest risk of ARF and whether the Strep A that causes skin sores is the same as Strep A that causes sore throats. Detecting Strep A in sick and healthy people helps scientists to understand how bacteria cause infection, why some children are at higher risk of disease compared to other children, and if our treatments and preventative interventions are working.

The information we collect will allow us to test the best treatment strategies to prevent skin sores, sore throats and rheumatic heart disease in Australia and the world.