Table 1.

In vitro activities of daptomycin and vancomycin in CAMHB and of daptomycin in calcium-supplemented CAMHB

Microorganisma (no. of isolates tested) and antimicrobial agentBroth mediumbMIC (μg/ml)
Range50%90%
Staphylococcus aureus
 Oxacillin-S (375)
  DaptomycinCa2+suppl.0.03–1.00.250.5
  DaptomycinCAMHB0.12–4.01.01.0
  VancomycinCAMHB≤1.0–2.0≤1.0≤1.0
 Oxacillin-R (172)
  DaptomycinCa2+suppl.0.12–2.00.250.5
  DaptomycinCAMHB0.5–8.01.01.0
  VancomycinCAMHB≤1.0–2.0≤1.0≤1.0
Coagulase-negative Staphylococcussp.
 Oxacillin-S (204)
  DaptomycinCa2+suppl.0.016–2.00.250.5
  DaptomycinCAMHB0.016–4.01.01.0
  VancomycinCAMHB≤1.0–4.0≤1.02.0
Coagulase-negative
 Oxacillin-R (339)
  DaptomycinCa2+suppl.0.12–2.00.250.5
  DaptomycinCAMHB0.25–8.01.01.0
  VancomycinCAMHB≤1.0–4.02.02.0
Micrococcus sp. (10)
 DaptomycinCa2+suppl.0.03–0.250.060.12
 DaptomycinCAMHB0.06–0.50.120.25
 VancomycinCAMHB≤1.0–2.0≤1.0≤1.0
Enterococcus faecalis
 Vancomycin-S (377)
  DaptomycinCa2+suppl.0.06–4.01.02.0
  DaptomycinCAMHB0.25–164.08.0
  VancomycinCAMHB≤1.0–4.0≤1.02.0
 Vancomycin-R (10)
  DaptomycinCa2+Suppl.0.12–4.02.04.0
  DaptomycinCAMHB0.25–8.08.08.0
  VancomycinCAMHB8.0–>16>16>16
Enterococcus faecium
 Vancomycin-S (50)
  DaptomycinCa2+suppl.0.12–8.02.04.0
  DaptomycinCAMHB0.12–>168.016
  VancomycinCAMHB≤1.0–2.0≤1.02.0
 Vancomycin-R (91)
  DaptomycinCa2+suppl.0.25–8.02.04.0
  DaptomycinCAMHB0.5–164.08.0
  VancomycinCAMHB8.0–>16>16>16
Other Enterococcus spp. (22)c
 DaptomycinCa2+suppl.0.25–8.01.04.0
 DaptomycinCAMHB1.0–164.016
 VancomycinCAMHB≤1.0–>162.0>16
Streptococcus agalactiae(208)
 DaptomycinCa2+suppl.0.03–0.50.120.25
 DaptomycinCAMHB0.06–1.00.51.0
 VancomycinCAMHB≤1.0≤1.0≤1.0
Streptococcus pyogenes(239)
 DaptomycinCa2+suppl.0.016–0.50.030.06
 DaptomycinCAMHB0.06–2.00.120.25
 VancomycinCAMHB≤1.0–2.0≤1.0<1.0
Streptococcus pneumoniae
 Penicillin-S (373)d
  DaptomycinCa2+suppl.0.06–0.50.120.25
  DaptomycinCAMHB0.06–1.00.50.5
  VancomycinCAMHB≤1.0≤1.0≤1.0
 Penicillin-I (92)d
  DaptomycinCa2+suppl.0.06–0.50.120.25
  DaptomycinCAMHB0.25–1.00.51.0
  VancomycinCAMHB≤1.0–2.0≤1.0≤1.0
 Penicillin-R (110)d
  DaptomycinCa2+suppl.0.06–0.50.120.25
  DaptomycinCAMHB0.25–2.00.51.0
  VancomycinCAMHB≤1.0≤1.0≤1.0
Beta-hemolytic Streptococcus sp. (32)e
 DaptomycinCa2+suppl.0.03–0.50.060.5
 DaptomycinCAMHB0.12–1.00.121.0
 VancomycinCAMHB≤1.0≤1.0≤1.0
Streptococcus viridans group (38)f
 DaptomycinCa2+suppl.0.03–8.00.52.0
 DaptomycinCAMHB0.06–8.01.02.0
 VancomycinCAMHB≤1.0≤1.0≤1.0
Lactobacillus sp. (10)
 DaptomycinCa2+suppl.≤0.008–8.00.54.0
 DaptomycinCAMHB≤0.008–160.58.0
 VancomycinCAMHB≤1.0–>16≤1.0>16
Corynebacterium sp. (29)g
 DaptomycinCa2+suppl.0.016–0.50.250.5
 DaptomycinCAMHB0.06–1.00.251.0
 VancomycinCAMHB≤1.0≤1.0≤1.0
Bacillus sp. (8)
 DaptomycinCa2+suppl.0.12–4.00.25
 DaptomycinCAMHB0.06–161.0
 VancomycinCAMHB≤1.0–2.0≤1.0
  • a S, susceptible; R, resistant; I, intermediate.

  • b CAMHB contained Ca2+ at 25 mg/liter, and Ca2+ suppl. was the same medium adjusted to 50 mg of Ca2+ per liter.

  • c Includes nine isolates of E. avium, eight of E. gallinarum, three of E. casseliflavus, 1 of E. durans, and 1 of E. raffinosus.

  • d Penicillin S, MIC of ≤0.06 μg/ml; penicillin I, MIC of 0.12 to 1.0 μg/ml; penicillin R, MIC of ≥2.0 μg/ml.

  • e Includes 5 serogroup C, 21 serogroup G, and 6 serogroup F isolates.

  • f Includes 12 S. milleri, 3 S. salivarius, 2 S. mitis, 4 S. sanguis, 2S. mutans, and 15 unidentified-species isolates.

  • g Includes 7 C. jeikeium isolates and 22 with no species identified.