London: Australian and British scientists studying a bacterium that causes scarlet fever, severe sore throat and a form of heart disease say they are closer to developing a vaccine that could one day prevent hundred of thousands of infections a year.

In a study in the journal Nature Genetics, the scientists found detailed differences between strains of Group A Streptococcus bacteria - known as Strep A - from 22 countries, but also found several molecular targets common across many strains, offering potential for vaccine development.

In this work, researchers from Britain's Wellcome Sanger Institute and Cambridge University, and from Australia's Doherty Institute and Queensland University, sequenced the DNA of more than 2000 Strep A samples from 22 countries, including in Africa and from Australian Aboriginal communities.

"Using all the data we collected, we narrowed down common genes in almost all strains of Strep A globally," said Mark Davies of the Wellcome Sanger and Doherty institutes, who co-led the work.