Table 2.

Characteristics of five chromosomal patterns ofemm genes associated with skin and throat infectionsa

Chromosomal patternbInfectionemm gene subfamilyM classcOpacity factor reactionUsual tissue site of isolationTypical M serotype(s)
APharyngitisSF1INegativeThroat1, 3, 6, 12, 17, 19, 24
BPharyngitisSF1-SF1INegativeThroat1, 5, 14
CPharyngitisSF1-SF3INegativeThroat18
DImpetigoSF4-SF1-SF3INegativeSkin33, 41, 42, 52, 53, 70
EPharyngitis or impetigoSF4-SF2-SF3IIPositiveThroat or skin2, 4, 11, 22, 28, 49, 75
  • a Data are from references 44, 56, 238, and 239.

  • b Acute rheumatic fever found in chromosomal patterns A to C (studies in United States); AGN found among all chromosomal patterns.

  • c Class 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).