Table 2.

Effects of fluoroquinolone C-8- and C-7-ring substituents on MICs for M. smegmatis

Straina and C-7-ring alkylMIC99 (μg/ml)
C-8-HC-8-OMeC-8-FC-8-ClC-8-Br
KD1163 (GryA+)
 None0.180.140.044
 Methyl0.100.0300.0360.0290.032
 Dimethyl0.0430.0280.0490.0580.11
C-3′-Ethyl0.120.0290.068
N-Ethyl0.110.0330.10
N-Isopropyl0.160.140.31
KD2012 (GyrA G89A)
 None0.860.180.42
 Methyl0.920.180.24
 Dimethyl0.630.180.24
C-3′-Ethyl1.00.280.37
N-Ethyl1.10.370.43
N-Isopropyl1.60.851.6
KD2008 (GyrA G89C)
 None4.70.940.94
 Methyl2.60.731.0
 Dimethyl3.80.911.2
C-3′-Ethyl3.20.650.73
N-Ethyl4.42.43.2
N-Isopropyl7.47.59.6
KD1987 (GyrA A91V)
 None1.70.410.54
 Methyl1.20.230.46
 Dimethyl0.980.410.47
C-3′-Ethyl1.20.380.53
N-Ethyl1.70.510.97
N-Isopropyl1.51.42.3
KD1990 (GyrA D95A)
 None1.80.310.65
 Methyl1.20.220.47
 Dimethyl0.960.280.43
C-3′-Ethyl2.60.30.67
N-Ethyl1.70.411.5
N-Isopropyl1.51.22.4
KD2003 (GyrA D95G)
 None4.50.831.3
 Methyl2.80.491.2
 Dimethyl3.00.711.2
C-3′-Ethyl3.80.651.4
N-Ethyl4.31.02.6
N-Isopropyl4.33.05.3
KD1995 (GyrA D95H)
 None3.50.571.1
 Methyl2.70.461.0
 Dimethyl3.60.590.92
C-3′-Ethyl3.80.541.2
N-Ethyl3.20.762.0
N-Isopropyl3.62.33.8
KD1998 (GyrA D95N)
 None4.60.811.3
 Methyl3.30.661.3
 Dimethyl3.40.931.3
C-3′-Ethyl3.60.631.4
N-Ethyl4.91.22.6
N-Isopropyl4.34.16.8
KD1991 (GyrA D95Y)
 None4.00.611.6
 Methyl2.60.471.1
 Dimethyl2.30.510.91
C-3′-Ethyl3.80.471.3
N-Ethyl3.60.812.3
N-Isopropyl4.62.45.8
Avg for GyrA variants
 None3.20.580.98
 Methyl2.20.430.86
 Dimethyl2.30.560.84
C-3′-Ethyl2.90.490.96
N-Ethyl3.10.932.0
N-Isopropyl3.62.84.7
  • a See footnote a of Table 1for amino acid abbreviations.