A significant proportion of annual healthcare costs is attributable to group A streptococcus infections. Molecular testing can expedite diagnosis, leading to improved patient management, and Focus Diagnostics has developed the Simplexa Group A Streptococcus Direct assay to do just that.

Streptococcus pyogenes, or group A streptococcus (GAS), is a pathogenic bacterium that can be found across the world and affects developed and developing countries alike.

GAS causes invasive and non-invasive infections, resulting in mild to severe disease. The non-invasive (superficial) infections generally include pyoderma, an infection of the skin, as well as pharyngitis and tonsillitis, more commonly known as strep throat.

Pharyngitis and tonsillitis constitute a significant health issue that affects all age groups, although they are more commonly found in children; it is estimated that nearly 7.3 million youngsters are seen as out-patients for streptococcal pharyngitis in the US alone every year.

GAS bacteria, which live in the nose and throat, are transferred by mucus droplets excreted through coughs and sneezes. They can also be passed on through contact with sores from a GAS skin infection. Some individuals harbour the bacteria without exhibiting symptoms and can unknowingly spread the infection.

GAS throat infections, if left untreated, can also trigger rare but more severe forms of disease, including acute rheumatic fever (ARF), an autoimmune disease that is also more common in children, as well as scarlet fever.

The GAS effect

The global burden of illness caused by GAS is not fully known, although it is estimated that there are more than 600 million cases of GAS pharyngitis worldwide each year. While epidemiological data from developing countries for most diseases is incomplete, it is well known that GAS is a significant cause of morbidity and mortality.

Rapid diagnosis, coupled with proper treatment, has been one of the major focuses in the healthcare community to diagnose and treat pharyngitis and reduce severe forms of GAS infection. Since viruses or other bacteria can also cause sore throats and pharyngitis, it is important that doctors perform a strep test (a simple swab of the throat) on patients to determine whether it is indeed a GAS infection and provide proper treatment.

Rapid antigen tests are commonly performed for strep throat but are not very accurate, often giving a negative result for someone infected with GAS. If that happens, a culture test will be performed to double-check the rapid test result.

A culture test is a time-consuming process – it can take up to two days to get a result, leading to significant delays in proper patient treatment. Doctors will usually prescribe antibiotics before the culture result is returned so that treatment is not delayed, but as a result patients may be unnecessarily taking antibiotics.

A molecular diagnostic solution

In order to provide proper patient care, it is essential to get a diagnostic result as soon as possible. Molecular methods such as PCR provide fast and reliable results, and enable physicians to make faster decisions related to patient care and management.

To meet this growing need, Focus Diagnostics has developed a fast and extremely easy to use real-time PCR assay for the direct detection of GAS. The Simplexa Group A Strep Direct assay runs on the Integrated Cycler and uses a proprietary chemistry that can detect the bacterial DNA without the need for external extraction and purification. The assay can be performed directly from a throat swab and provides results in about an hour. It is intended for the in-vitro qualitative detection of GAS in human patients showing signs and symptoms of infection.