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. 2010 Dec 20;55(3):1266–1269. doi: 10.1128/AAC.00927-10

TABLE 1.

Bacterial strains and fluoroquinolone MIC and MBCs

E. coli strain/plasmid gene Relevant features Plasmid containing PMQRa gene Ciprofloxacin susceptibilityb MIC (μg/ml)c
MBC (μg/ml)
CIP LVX MXF NFX CIP LVX MXF NFX
ATCC 25922 Wild type None S 0.002 0.008 0.008 0.015 0.015 0.03 0.015 0.03
ATCC/qnrA Wild type pBK-QnrA1 S 0.125 0.5 0.25 0.5 0.125 0.5 0.5 1
ATCC/qnrB Wild type pBK-QnrB1 S 0.125 0.125 0.25 0.25 0.125 0.25 1 0.5
ATCC/qnrS Wild type pBK-QnrS1 S 0.125 0.5 0.25 0.5 0.25 0.5 0.25 1
ATCC 25922-S83L GyrA Ser83Leu None S 0.125 0.125 0.06 0.125 0.125 0.25 0.125 0.5
ATCC-S83L/qnrA GyrA Ser83Leu pBK-QnrA1 S 0.5 0.5 0.5 2 0.5 0.5 0.5 2
ATCC-S83L/qnrB GyrA Ser83Leu pBK-QnrB1 S 0.5 0.25 0.5 1 0.5 0.5 0.5 1
ATCC-S83L/qnrS GyrA Ser83Leu pBK-QnrS1 S 1 1 1 2 1 2 2 4
ATCC 25922-S80R ParC Ser80Arg None S 0.004 0.008 0.008 0.03 0.004 0.008 0.008 0.03
ATCC-S80R/qnrA ParC Ser80Arg pBK-QnrA1 S 0.25 0.25 0.5 0.5 0.25 0.5 0.5 2
ATCC-S80R/qnrB ParC Ser80Arg pBK-QnrB1 S 0.125 0.25 0.5 0.5 0.25 0.5 0.5 0.5
ATCC-S80R/qnrS ParC Ser80Arg pBK-QnrS1 S 0.125 0.25 0.25 0.5 0.25 0.25 0.5 0.5
ATCC 25922-S83L-S80R GyrA Ser83Leu, ParC Ser80Arg None S 0.25 0.25 0.25 2 2 0.25 0.25 2
ATCC-S83L-S80R/qnrA GyrA Ser83Leu, ParC Ser80Arg pBK-QnrA1 I 2 2 2 8 4 4 4 64
ATCC-S83L-S80R/qnrB GyrA Ser83Leu, ParC Ser80Arg pBK-QnrB1 S 1 1 1 4 2 1 2 4
ATCC-S83L-S80R/qnrS GyrA Ser83Leu, ParC Ser80Arg pBK-QnrS1 I 2 4 2 8 4 4 4 16
a

PMQR, plasmid-mediated quinolone resistance.

b

S and I, susceptible and intermediate susceptibility, respectively, according to CLSI guidelines (2).

c

MICs determined by microdilution for ciprofloxacin (CIP), levofloxacin (LVX), moxifloxacin (MXF), and norfloxacin (NFX).