Table 1.

Sources and antibiotic phenotypes of 30 strains of ciprofloxacin-resistant clinical E. coli isolates (May to August 1999)

StrainSpecimenMIC (μg/ml)a
TetbChlbGencAmpbTimcPtacFtxcNorb,d
CH1Urine72870.521841.50.0664
CH2Urine1.3125376256120.2250
CH3Drainage>400624>4002563256167
CH4Blood15310241912440.492
CH5Urine832501.52581640.3194
CH6Sputum>400162426232124250
CH7Pus>40025932147630.1106
CH8Pus13825024>4001281.50.369
CH9Urine30270.8>4002440.3117
CH10Blood258258641912440.4250
CH11Drainage>400364182840.4158
CH12Pus189464>4003240.497
CH13Vaginal swab50316192>400>25620.0625
CH14Blood15646>256>4003220.0967
CH15Abscess97162476648275
CH16Blood128147481429660.528
CH17Blood1422496414225616828
CH18Urine111250641731640.221
CH19Vaginal swab1.440.8>4002564>25651
CH20Urine26723664>4002563>256156
CH21Sputum16018711293230.258
CH22Sputum1672362562676424669
CH23Vaginal swab139213>256>400>25664>256125
CH24Throat16925919214219216624
CH25Sputum236642096430.428
CH26Urine23014323161640.4117
CH27Urine448322449640.5236
CH28Drainage191187483514820.433
CH29Blood7225896981640.4117
CH30Urine>40019322224830.3158
  • a Tet, tetracycline; Chl, chloramphenicol; Gen, gentamicin; Amp, ampicillin; Tim, ticarcillin-clavulanate; Pta, piperacillin-tazobactam; Ftx, cefotaxime; Nor, norfloxacin.

  • b By gradient plate.

  • c By E-test.

  • d All strains showed ciprofloxacin MICs of >32 μg/ml. The susceptible E. coli K-12 strain AG100 showed a ciprofloxacin MIC of 0.015 μg/ml (by E-test) and a norfloxacin MIC of 0.08 μg/ml (by gradient plate).