Diagnosis is by a swab of the affected area for laboratory testing. A Gram stain is performed to show Gram-positive cocci in chains. Then, the organism is cultured on blood agar with an added bacitracin antibiotic disk to show beta-hemolytic colonies and sensitivity (zone of inhibition around the disk) for the antibiotic. Culture on agar not containing blood, and then performing the catalase test should show a negative reaction for all streptococci. S. pyogenes is CAMP and hippurate tests negative. Serological identification of the organism involves testing for the presence of<unk> -A-specific polysaccharide in the bacterium's cell wall using the Phadebact test. The rapid pyrrolidonyl arylamidase (PYR) test is used for the presumptive identification of<unk>  A beta-hemolytic streptococci. GBS gives a negative finding on this test.
Group A streptococcal infection
Group B streptococcal infection
Side effects of penicillin
Pneumococcal infection
Staphylococcal infection
Periodic fever syndrome
Streptococcal pharyngitis
Sulfonamide hypersensitivity syndrome