Table 1.

Fluoroquinolone susceptibilities and QRDR statuses of isogenic mutants of S. pneumoniae strain 7785 selected with ciprofloxacin, sparfloxacin, or gemifloxacin

StrainaMIC (μg/ml) ofb:Mutation(s) in the QRDR ofc:
CIPSPARGEMIGyrAParC
77851–20.50.06
1C130.50.06
2C680.50.12–0.25S79Y
2C780.50.12–0.25S79F
1S1220.12–0.25S81F
1S4220.12–0.25S81Y
3C464161S81YS79Y
2S164160.5S81FS79Y
2S416160.5S81FD83N
1GM42–410.12–0.25
1GM5220.25S81F
1GM724–80.25E85K
1GM9220.25E85K
1GM10220.25S81Y
1GM11220.25S81F
2GM164321S81FS79F
2GM264321S81FS79Y
2GM1764321S81FS79Y
2GM1864321S81FS79Y
  • a Mutations in strains selected with ciprofloxacin (C) and sparfloxacin (S) are described in references25 and 27, respectively. For strains selected with gemifloxacin (GM), gyrA mutations were S81F (TCC→TTC), E85K (GAA→AAA), and S81Y (TCC→TAC).ParC mutations were S79F (TCT→TTT) and S79Y (TCT→TAT). None of the strains harbored QRDR mutations in gyrB orparE.

  • b CIP, ciprofloxacin; SPAR, sparfloxacin; GEMI, gemifloxacin.

  • c —, wild-type QRDR sequence.