Table 3.

Percentages of agreement and correlation indexes between MICs obtained by the NCCLS reference AST method and MICs obtained both visually and spectrophotometricallya

Method of endpoint determinationTime of incubation (h)Antifungal agent
AMB5FCFLCITCKTCVRC
%r%r%r%r%r%r
Visual inspection24920.608930.895920.874940.849990.824960.897
48970.673980.848930.847950.876970.790950.886
Spec-50%24720.286980.913970.899960.886950.902970.900
48870.512910.783950.885940.888950.886940.904
Spec-80%24910.553960.805920.873920.815880.711890.807
48920.421940.799910.806890.774910.734900.846
Spec-95%24980.654
48940.623
  • a The NCCLS reference method uses RPMI, an inoculum of 103 CFU/ml, and a visual reading of optical density at 48 h of incubation. The tested method uses RPMI–2%G, an inoculum of 105 CFU/ml, and spectrophotometric determinations of optical density after 24 and 48 h of incubation. Data are for 60 strains tested. %, percentage of agreement between AST methods; r, correlation index expressed over a maximum value of 1. An asterisk indicates a correlation index with a statistically significant P value of <0.01.