Table 1.

Growth-inhibitory effect of 13-CPTC alone or in combination with doxycycline against different TC-susceptible and TC-resistant bacterial strains

DrugMIC (μg/ml)a for:
E. coliS. aureusRN450dE. hirae ATCC 9790e
ML308-225bD31m4c
WTTet(A)Tet(B)WTTet(B)WTTet(K)WTTet(L)Tet(M)
13-CPTC2050500.86.250.51.560.80.393.12
Doxycycline0.550>500.512.50.2512.50.56.2525
Doxycycline + 13-CPTCNTf 3.12 + 1.561.56 + 1.56NT1.56 + 0.39NT3.12 + 0.78NT1.56 + 0.196.25 + 1.56
Effect on growthg SSSAAA
  • a Concentration of compound which inhibited growth after 18 h in L broth after incubation at 37°C. Values are representative of those from at least three experiments. The MIC of tetracycline was ≥50 μg/ml for all determinants.

  • b Wild type (WT) or containing Tet(A) specified by plasmid pIP15 or Tet(B) specified by plasmid R222.

  • c Wild type or containing Tet(B) specified by plasmid pHCM1.

  • d Wild type or bearing Tet(K) specified by plasmid pT181.

  • e Wild type or bearing Tet(L) specified by plasmid pMV158 or Tet(M) specified by plasmid pAM211.

  • f NT, not tested.

  • g S, synergy; A, additive.