TABLE 3.

DNA mutations and amino acid changes leading to rifampin nonsusceptibility in S. pneumoniae in vitro

StrainaParent strainaRifampin concn used for selection (mg/liter)bMIC (mg/liter)DNA sequence changeAmino acid changecAlteration in cluster
104.72-INone, wild typeNone0.032NoneNoneNone
104.72-II104.72-I0.51ATC to AACI545NII
104.72-III104.72-I10>256CAC to GACH499DI
104.72-II4104.72-II464AAC to AAAN545KII
104.72-II10104.72-II1096AAC to AAAN545KII
104.72-II50104.72-II50>256ATC to AACI545NI and II
104.72-II50104.72-IICAC to TACH499Y
111.46-INone, wild typeNone0.016NonenoneNone
111.46-II111.46-I0.50.5ATC to CTCI545LII
111.46-III111.46-I10>256TCT to TTTS495FI
111.46-II4111.46-II4>256ATC to CTCI545LI and II
111.46-II4111.46-IICAC to CTCH499L
111.46-II10111.46-II10>256ATC to CTCI545LI and II
111.46-II10111.46-IIGAC to TACD489Y
111.46-II50111.46-II50>256ATC to CTCI545LI and II
111.46-II50111.46-IICGT to CATR502H
111.81-INone, wild typeNone0.032NoneNoneNone
111.81-II111.81-I0.51.5ATC to AACI545NII
111.81-III111.81-I10>256CAC to GACH499DI
204.26-INone, wild typeNone0.016NoneNoneNone
204.26-II204.26-I0.50.75ATC to AACI545NII
204.26-III204.26-I10>256TCT to TTTS495FI
204.26-II4204.26-II412ATC to AACI545NII
204.26-II204.26-IITTG to GTGL544V
204.26-II10204.26-II1024ATC to AACI545NI and II
204.26-II10204.26-IIGAC to AACD489N
204.26-II50204.26-II50>256ATC to AACI545NI and II
204.26-II50204.26-IICAG to AAGQ486K
777-INone, wild typeNone0.032NoneNoneNone
777-II777-I0.52ATC to AACI545NII
777-III777-I1012TCT to TTTS495FI
777-II4777-II4>256ATC to AACI545NI and II
777-II4777-IICAG to CACQ483H
777-II10777-II10>256ATC to AACI545NI and II
777-II10777-IICAC to TACH499Y
777-II50777-II50>256ATC to AACI545NI and II
777-II50777-IICGT to TGTR502C
  • a Rifampin-susceptible S. pneumoniae strains are designated with the suffix I; their mutants with low-level and high-level resistance are designated with the suffixes II and III, respectively.

  • b Concentration used for selection of mutants with spontaneous rifampin resistance.

  • c The numbering is according to that for S. pneumoniae strain R6.