TABLE 1

Antimicrobial activity and MIC distribution for oritavancin against a challenge set of molecularly characterized Gram-positive clinical isolates displaying elevated linezolid MIC results

Organisma (no. of isolates tested)MIC (μg/ml) at:No. (cumulative %) inhibited at oritavancin MIC (μg/ml) of:
50%90%≤0.0080.0150.030.060.12
S. aureus (25)0.030.060 (0.0)3 (12.0)15 (72.0)6 (96.0)1 (100.0)
    cfr-carrying only (13)0.030.060 (0.0)3 (23.1)6 (69.2)3 (92.3)1 (100.0)
CoNS (80)0.030.127 (8.8)6 (16.2)33 (57.5)25 (88.8)9 (100.0)
E. faecalis (13)b0.0150.123 (23.1)7 (76.9)1 (84.6)0 (84.6)1 (92.3)
E. faecium (32)0.0150.1214 (43.8)4 (56.2)6 (75.0)2 (81.2)6 (100.0)
    VanA phenotype (24)0.030.126 (25.0)4 (41.7)6 (66.7)2 (75.0)6 (100.0)
  • a All S. aureus isolates, except 1, were methicillin (oxacillin) resistant. VanA phenotype, vancomycin and teicoplanin MIC results of ≥8 and ≥16 μg/ml, respectively. CoNS, coagulase-negative staphylococci, including 2 S. capitis, 1 S. cohnii, 69 S. epidermidis, 5 S. haemolyticus, and 3 S. hominis isolates.

  • b One vancomycin-resistant E. faecalis isolate showed an oritavancin MIC value of 1 μg/ml.