TABLE 1

Summary of MIC results for Ureaplasma parvum and U. urealyticum clinical isolates

Drug used by speciesMIC data (μg/ml)No. (%) of resistant isolatesa
RangeMIC50MIC90
U. parvum (n = 60)
    Azithromycinb≤0.5–212NA
    Chloramphenicolb≤0.5–212NA
    Ciprofloxacin0.5–1622NA
    Clindamycinc≤0.22–3.51.83.5NA
    Erythromycin0.5–4120
    Doxycycline≤0.25–2≤0.25≤0.25NA
    Gentamicinc1–211010NA
    Levofloxacin≤0.25–40.511 (1.6)
    Tetracycline≤0.25–8≤0.250.51 (1.6)
U. urealyticum (n = 13)
    Azithromycinb≤0.5–424NA
    Chloramphenicolb1–424NA
    Ciprofloxacin2–444NA
    Clindamycinc1.8–28.33.514NA
    Erythromycin1–8440
    Doxycycline≤0.25≤0.25≤0.25NA
    Gentamicinc10–422142NA
    Levofloxacin0.5–1110
    Tetracycline≤0.25–1110
  • a Resistance determined by using CLSI interpretive guidelines. NA, not applicable, as there are no established breakpoints. Breakpoints are available only for levofloxacin at ≥4 μg/ml, erythromycin at ≥16 μg/ml, and tetracycline at ≥2 μg/ml.

  • b Compounds tested at doubling dilutions from 64 to 0.5 μg/ml; all others were tested from 64 to 0.25 μg/ml.

  • c End MICs adjusted to account for drug potency.