Infectious disease scientists at the Illawarra Health and Medical Research Institute (IHMRI) have found that people with a common blood group could be more susceptible to Streptococcal infections.Senior Research Fellow Dr Martina Sanderson-Smith, and Post-Doctoral Researcher Dr David De Oliveira, from the University of Wollongong’s School of Biological Sciences, have published their work in a top-ranking international microbiology publication, mBIO. There are many different types of Streptococcal infection, from mild sore throats to deadly infections of the blood or organs. Repeated infections can lead to chronic conditions, such as rheumatic heart disease. “Rather than focussing on how Streptococcus spreads like other studies, we took a different approach. We know that some people are more susceptible to Streptococcal infections. We wanted to see if there are other biological reasons that increase the risks, and understand why some people suffer repeated infections,” explains Dr Martin Sanderson-Smith. For his PhD thesis, Dr De Oliveira studied Streptococcus pyogenes (Group A Streptococcus or GAS), that is responsible for over 500,000 deaths worldwide each year. Using IHMRI’s state-of-the-art laboratories, he investigated a highly virulent clone of GAS (M1T1 GAS) that is present in many cases of pharyngitis and invasive infections. Dr De Oliveira found that people with blood group O could be more prone to infections caused by M1T1 GAS. The O blood group is the most common group among urban populations in western countries, including Australia.
“This streptococcus interacts with, and attaches to, numerous sugar molecules that sit on blood cells,” explains Dr David De Oliveira. “These sugar molecules, known as glycans, are prevalent in group O blood. Our data suggests that these glycans act as a bridge for the M1T1 GAS to colonise humans, allowing it to flourish in the body.”Their work has already captured the attention of the medical research world. The researchers will present their findings at international conferences later in the year, including The Lancefield International Symposium on Streptococci and Streptococcal Disease. To progress understanding of the link between Streptococcus and blood groups, they will embark on a new project—studying saliva samples taken from people colonised with GAS, in collaboration with researchers at the Murdoch Childrens Research Institute. The researchers also hope one day to take their findings out of the laboratory and into new treatments for people suffering from Streptococcal infections. “One of the outcomes we are striving for is a non-antibiotic treatment for children with sore throats,” states Dr Martina Sanderson-Smith. “A sore throat is one of the most common reasons children are prescribed antibiotics, but we are becoming more aware that antibiotic overuse can be a problem, so developing non-antibiotic treatments for bacterial infections is important.” Dr Sanderson-Smith and Dr De Oliveira worked with other researchers from the Department of Chemistry and Biomolecular Sciences at Macquarie University; the Australian Infectious Diseases Research Centre at the University of Queensland; the Centre for Immunity, Infection and Inflammation at the University of California, San Diego; and the Institute for Glycomics at Griffith University.