TABLE 1.

Susceptibilities of C. jejuni 81-176, 21190, and their cmeB mutants to different antimicrobials

AntimicrobialMIC (μg/ml)
81-1769B6Fold differenced21190cmeB isogenic mutantFold differencee
Ciprofloxacin0.3130.03980.1560.0208
Norfloxacin0.0780.03920.0780.0392
Nalidixic acid1.250.62521.250.6252
Erythromycin0.0780.02040.6250.0416
Ampicillin0.3120.0103262.5b62.5b
Cefotaxime1.600.0062561.560.09716
Rifampin1000.78128500.7864
Trimethoprim>200>200c>200>200
Cycloheximide>500>500>500>500
Tetracycline50a6.25a80.3130.0398
Chloramphenicol0.8500.42524.252.12
Gentamicin0.2650.13320.390.22
Polymyxin B3.03.03.03.0
Protamine25.012.522512.52
Ethidium bromide0.6250.07881.250.07816
CoCl23121562312312
CuCl23911962391391
ZnSO47878156156
Sodium dodecyl sulfate25062.5412531.34
Cholic acid6,25098643,1259832
Chenodeoxycholic acid50,00012.54,0001,5606.1256
Taurocholic acid>50,000780>64>50,000780>64
Deoxycholic acid10,000101,0001,25019.564
  • a Both wild-type 81-176 and 9B6 contain the pTet plasmid that carries tet(O) (1).

  • b Both wild-type 21190 and its cmeB mutant produce β-lactamase as determined by Cefinase disk assay.

  • c —, no MIC difference was observed.

  • d Difference in MICs for 81-176 and 9B6.

  • e Difference in MICs for 21190 and cmeB isogenic mutant.