Table 2.

MIC of macrolides in the presence and absence of inducera for erythromycin-resistant strains

StrainMIC (μg/ml) with or without inducerb
ErythromycinRokitamycinMidecamycinLeucomycinClarithromycinc(−)Azithromycin (−)Roxithromycin (−)PCR product
++++ermmefE
S. oralisSO12>1,024>1,0241>2564>1288>1,024>1,024>1,024>1,024+
S. mitisSO13>1,024>1,0242>25616>12816>1,024>1,024>1,024>1,024+
S. mitisE251251212564>1284>512>512>512>512+
S. oralisO14512>512<0.125>256<0.063>128<0.25>51225612++
S. oralisE21512>51215122>1284>512256642+
S. mitisE3512>128816>128>128>128>25664>512>512+
S. mitisE113216<0.0310.250.250.50.250.5326464
S. oralisE1716160.25<0.250.1250.1250.1250.2583232+
S. mitisE27168<0.25<0.25<0.031<0.063<0.031<0.12532>32>32
S. oralisO2488<0.25<0.250.125<0.0630.063<0.12543216+
S. mitisE108 NDc0.5NDNDNDNDND81616
S. mitisE188ND0.25NDNDNDNDND8168
S. mitisE308320.125<0.250.250.5<0.250.583232+
  • a The inducing concentration of erythromycin was 0.25 μg/ml.

  • b −, absence of inducer; +, presence of inducer. Note that the MICs of clarithromycin, azithromycin, and roxithromycin in the presence of inducer were not determined.

  • c ND, not determined.