Group A Streptococcus
Orange to rouge
Other oral Streptococci
Colourless or blue
Streptococcus pyogenes infection is responsible for nearly all Streptococci caused bacterial pharyngitis, therefore the specific target of current strep throat screening methods.
Rapid and accurate detection of this microorganism in throat specimens, particularly in children and elderly patient, is essential to start antibiotic therapy, to prevent complications and reduce the risk of transmission to other persons.
Patients are commonly tested for the presence of GAS using antigen detection test that provide results in 15-20 minutes, but with a positive predictive value of ~70-90 % and a rate of false negatives ~10-20 %. However, throat culture is used primarily as a confirmatory test with definitive results requiring 24 h.
CHROMagar™ StrepA is a new chromogenic formulation allowing for an easy to read and straight forward color differentiation of GAS colonies (in orange to red) among the other bacteria in the complex throat flora (colorless or blue colonies).