TABLE 1.

Paradoxical caspofungin effect

Isolate (method)Growth at caspofungin concn (μg/ml) of:
0a0.0120.0250.050.090.190.390.781.563.136.2512.5
03-178 (growthb)4+NDdNDNDNDND00Trace1+2+Trace
95-68 (growthb)4+3+2+1+Trace00002+2+2+
95-68 (MFC platec)ConfluentNDNDND1700130TNeTNTN
  • a Control.

  • b Growth relative to 4+ control, where 3+ is less than control to ≈80% turbidity compared to control, 2+ is ≈50 to 80%, 1+ is 50 to 25%, trace is >0 to 25%, and 0 is a clear tube. Visual turbidity readings were confirmed by spectrophotometer (10). The standard range for caspofungin susceptibility testing for clinical isolates is 0.39 to 12.5 μg/ml, as stated in the text.

  • c Colonies enumerated on each plate are shown. Each colony represents 1.3 to 4% of the CFU in the original inoculum [microscopically enumerated inoculum, 103 yeasts/ml; acceptable variation in CFU (0.5 to 1.5) × 103/ml] (28).

  • d ND, not done.

  • e TN, too numerous to count.