TABLE 2.

Characteristics of five chromosomal patterns of emm genes associated with skin and throat infections^a

Chromosomal patternb	Infection	emm gene subfamily	M classc	Opacity factor reaction	Usual tissue site of isolation	Typical M serotype(s)
A	Pharyngitis	SF1	I	Negative	Throat	1, 3, 6, 12, 17, 19, 24
B	Pharyngitis	SF1-SF1	I	Negative	Throat	1, 5, 14
C	Pharyngitis	SF1-SF3	I	Negative	Throat	18
D	Impetigo	SF4-SF1-SF3	I	Negative	Skin	33, 41, 42, 52, 53, 70
E	Pharyngitis or impetigo	SF4-SF2-SF3	II	Positive	Throat or skin	2, 4, 11, 22, 28, 49, 75

^aData are from references 44, 56, 238, and 239. 

^bAcute rheumatic fever found in chromosomal patterns A to C (studies in United States); AGN found among all chromosomal patterns. 

^cClass I M proteins were identified by reactivity with anti-M protein MAbs 10.B6 and 10.F5; class II M proteins do not react with these MAbs (50, 52).