TABLE 2.
Interlaboratory agreement between test methodsa
| Species (no. of isolates) | Median (range) MIC (mg/liter) by: |
Mean (range) difference (% of isolates with differences of >2 2-fold dilutions) |
|||||||
|---|---|---|---|---|---|---|---|---|---|
| EUCAST | CLSI | Etest (24 h) | Etest (48 h) | EU vs CL | EU vs Et24 | EU vs Et48 | CL vs Et24 | CL vs Et48 | |
| C. albicans (584) | 0.004 (≤0.002–0.016) | 0.002 (≤0.002–0.016) | 0.008 (0.004–0.016) | 0.008 (0.008–0.016) | 1.1 (−2 to 4)* (17) | 0.1 (−2 to 2) (0) | −0.1 (−2 to 2)* (0) | −1 (−9 to 1)* (6) | −1.2 (−4 to 1)* (11) |
| C. glabrata (86) | 0.016 (0.004–0.031) | 0.008 (≤0.002–0.016) | 0.008 (0.004–0.008) | 0.008 (0.004–0.016) | 1.2 (−2 to 4)* (19) | 1 (−1 to 2)* (0) | 0.9 (−1 to 2)* (0) | −0.5 (−9 to 2) (5) | −0.2 (−2 to 2) (0) |
| C. tropicalis (180) | 0.031 (0.031–0.031) | 0.008 (≤0.002–0.031) | 0.016 (0.008–0.016) | 0.016 (0.008–0.032) | 1.7 (−5 to 6)* (31) | 1.1 (0 to 3)* (2) | 0.7 (0 to 3)* (1) | −0.6 (−3 to 6)* (17) | −0.9 (−4 to 5)* (20) |
| C. parapsilosis (122) | 2 (1–2) | 0.5 (0.25–2) | 0.5 (0.25–1) | 1 (0.5–4) | 1.1 (0 to 8)* (6) | 1.4 (0 to 3)* (4) | 0.8 (−1 to 2)* (0) | 0.3 (−7 to 2) (1) | −0.3 (−8 to 2) (2) |
| C. krusei (30) | 0.125 (0.063–0.25) | 0.094 (0.031–0.125) | 0.064 (0.032–0.125) | 0.064 (0.032–0.125) | 0.8 (0 to 2)* (0) | 1.2 (0 to 2)* (0) | 1 (0 to 2)* (0) | 0.4 (−1 to 2) (0) | 0.2 (−1 to 2) (0) |
| Other Candida spp. (97) | 0.1875 (0.016–1) | 0.094 (≤0.002–4) | 0.032 (0.008–0.5) | 0.063 (0.008–1) | 1.4 (−5 to 9)* (28) | 1.5 (−1 to 4)* (7) | 0.9 (−1 to 3)* (4) | 0 (−7 to 7) (15) | −0.5 (−8 to 6) (20) |
| All strains (1,099) | 0.016 (0.004–2) | 0.008 (≤0.002–2) | 0.012 (0.008–1) | 0.016 (0.008–2) | 1.2 (−5 to 9)* (19) | 0.6 (−2 to 4)* (1) | 0.3 (−2 to 3)* (1) | −0.6 (−9 to 7)* (8) | −0.9 (−8 to 6)* (11) |
a
Comparison of results by the EUCAST method (EU), the CLSI method (CL), and the Etest read after 24 h (Et24) and 48 h (Et48), determined in different laboratories. Median (range) MICs are presented for each method, whereas for the comparison, the average (range) 2-fold-dilution difference is shown (together with the percentage of isolates with differences of >2 2-fold dilutions). Asterisks indicate a P value of <0.001 by a paired t test.