Quick diagnosis test for streptococcal strains

Mar 8 2007

A streptococcal infection may initially cause nothing more than a relatively harmless sore throat. It can, however, also lead to potentially fatal disease or lifelong disability.

The outcome of a primary streptococcal infection depends on the strain of bacteria involved and frequently on the individual susceptibility of the patient.

Scientists are now in the process to develop a test that will allow a quick diagnosis of streptococcal strains with potential to cause serious disease. Researchers are evaluating patient samples from India, where children in particular have a high frequency of exposure to streptococcal infections.

The research project, known as ASSIST, includes partners from Europe and India and is being coordinated by the Helmholtz Centre for Infection Research in Braunschweig. The European Union is funding the project with Euro 1.5 million.

Experts estimate that every year streptococcal infections occur in around 600 million people. Most of them experience brief throat or larynx infections. Some two million others, however, suffer from potentially harmful complications. Among these are so-called invasive illnesses which destroy cells and tissue, as well as rheumatic fever, which often leads to cardiac damage.

"Rheumatic heart disease, as a secondary effect of streptococcal infections, progresses very dramatically," explains Prof. Singh Chhatwal, departmental director at the Helmholtz Centre and coordinator of the ASSIST project. "It occurs primarily in children and frequently only a cardiovalvular transplant can save the child." Of the 15 million children worldwide suffering from rheumatic heart disease, six million alone live in India. "The proper diagnostic methods are often lacking, resulting in inadequate treatment by antibiotics, “says Chhatwal, who was born in India and has first-hand knowledge of the situation there. There are grounds for optimism, however. Less than ten percent of the streptococcal strains are capable of triggering serious complications. "If we had an effective test to quickly diagnose whether a patient is infected with a dangerous strain, then we could concentrate on these cases," notes Chhatwal and points out that because the number of these cases is much lower than the total number of infected cases it would be much easier to introduce proper antibiotic treatments in poor countries.

Researchers working on the ASSIST project will be gathering information about the streptococcal strains prevalent in India over the next few years. They will also be examining the congenital dispositions of people that make them more susceptible to dangerous pathogens. When this information is collected and evaluated they hope to develop a quick test for streptococcal infections. One avenue being explored is a process to identify specific surface molecules or genes that appear only in dangerous strains. Data will be gathered from patients in the age group most at risk in the most affected region of the world. "The Indian project partners," says Chhatwal," will take and evaluate throat swabs from 25,000 Indian school children."