Species of Gram positive bacteria from the genus Streptococcus are capable of causing infections in humans. There are several disease-causing strains of streptococci. These strains have been categorized into groups (A, B, C, D, and G), according to their behavior, chemistry, and appearance.

Each group causes specific types of infections and symptoms. For example, group A streptococci are the most virulent species for humans and are the cause of "strep throat," tonsillitis, wound and skin infections, blood infections (septicemia), scarlet fever, pneumonia, rheumatic fever, Sydenham's chorea (formerly called St. Vitus' dance), and glomerulonephritis.

While the symptoms affected individuals experience may be suggestive of a streptococcal infection, a diagnosis must be confirmed by testing. The most accurate common procedure is to take a sample from the infected area for culture, a means whereby the bacteria of interest can be grown and isolated using various synthetic...