TABLE 1

CIP MICs for low-level quinolone-resistant E. coli strains harboring qnr determinants in MHB and urine at different pH values

StrainGenotypeCIP MIC (μg/ml) fora:
MHB (pH 7.4)UR (pH 7)UR (pH 6)(UR pH 5)
O2nO2O2nO2O2nO2O2nO2
Isogenic
    ATCC 25922pBK-CMV0.0060.0150.0150.030.060.2511
    EC10pBK-qnrA10.2510.251443232
    EC11pBK-qnrB10.250.50.251443232
    EC12pBK-qnrC0.1250.50.251443232
    EC13pBK-qnrD10.060.060.030.250.5188
    EC14pBK-qnrS10.1250.50.252483232
UPEC
    PMQR 2qnrS10.250.50.52886464
    PMQR 11qnrB40.250.50.51886464
    PMQR 13qnrS10.250.5128812864
    PMQR 30qnrB40.1250.50.250.5486464
    PMQR 51qnrB40.2510.51886464
    PMQR 73qnrA10.250.50.50.5443232
    PMQR 88qnrS10.250.50.50.5446432
    PMQR 91qnrS10.250.50.52486432
    PMQR 100qnrB40.1250.50.250.5443264
  • a Resistant values, according to CLSI guidelines, are shown in bold. MHB, Mueller-Hinton broth; UR, urine; O2, aerobic conditions; nO2, anaerobic conditions; UPEC, uropathogenic E. coli.