Article Figures & Data
Figures
- FIG. 1.
Assessment of the in vitro interaction between voriconazole (VCZ) and terbinafine (TB) against a clinical S. prolificans strain (AZN87898) based on the LA-based models using the SP48 data. (Ai) Checkerboard showing the percentage of growth for each combination, combinations with more than 50% growth (light grey area), the MIC-2 of voriconazole and terbinafine (percentages in boldface type) as well as the iso-effective combinations based on which the ΣFIC-2 indices were calculated (dark grey area), combinations with ΣFIC-2 indices lower than 0.5 (underlined percentages) and the combination with the lowest ΣFIC-2 index (0.20), corresponding to the FICi-2 (percentage shown in black cell). (Aii) Corresponding isobologram with the additivity line (dashed line). (B) The 3-D (i) and contour (ii) plots of the percent synergy calculated with the Greco model with the following fitted parameters (means ± 95% CI): IC50,TB = 5.33 ± 0.57, IC50,VCZ = 2.63 ± 0.31, mTB = − 0.51 ± 0.04, mVCZ = −1.1 ± 0.11, α = 13.9 ± 1.6.
- FIG. 2.
Assessment of the in vitro interaction between voriconazole (VCZ) and terbinafine (TB) against a clinical S. prolificans strain (AZN7898) based on BI-based models using the SP48 data. (A) The 3-D (i) and contour (ii) plots of the percent synergy calculated with the nonparametric approach, which resulted in 700% synergy. (B) The 3-D (i) and contour (ii) plots of the percent synergy calculated with the semiparametric approach, which resulted in 1,118% synergy with the following fitted parameters (means ± 95% CI) of the Emax model: IC50,TB = 19.9 ± 6.7, mTB = −0.76 ± 0.21, IC50,VCZ = 2.8 ± 0.7, mVCZ = −1.3 ± 0.37.
Tables
- TABLE 1.
Susceptibilities of S. prolificans strains against various azoles alone and in combination with terbinafinea
Combination and strain GM MIC-1 (range) Drug alone Drugs in combination Azole TB Azole TB VCZ and TB 7898 9.51 (8-16) >64 (>64) 0.71 (0.13-2) 9.51 (2-32) 7901 6.73 (4-8) >64 (>64) 0.25 (0.03-1) 6.73 (4-16) 7902 6.73 (4-8) >64 (>64) 0.5 (0.13-1) 8 (8) 7906 8 (8) >64 (>64) 1 (0.5-2) 9.51 (8-16) 7918 9.51 (8-16) >64 (>64) 1.19 (0.5-2) 11.31 (2-32) MCZ and TB 7898 64 (32->64) >64 (>64) 1.19 (0.25-4) 2.83 (2-4) 7901 >64 (>64) >64 (>64) 2.83 (2-4) 2 (1-4) 7902 45.25 (8->64) >64 (>64) 2 (0.13-8) 2 (2) 7906 >64 (>64) >64 (>64) 2.83 (2-4) 1.41 (1-4) 7918 26.91 (8->64) >64 (>64) 0.84 (0.13-2) 2.38 (2-4) ICZ and TB 7898 >32 (>32) >64 (>64) 1 (0.5-2) 16 (16) 7901 >32 (>32) >64 (64->64) 10.01 (4-16) 12.7 (8-16) 7902 >32 (>32) >64 (64->64) 4 (0.5-16) 8 (8) 7906 >32 (>32) >64 (>64) 3.17 (1-16) 8 (2-16) 7918 >32 (>32) >64 (>64) 4 (1-16) 10.08 (2-16) ↵a Based on the MIC-1 and SP72 data. Abbreviations: VCZ, voriconazole; MCZ, miconazole; ICZ, itraconazole; TB, terbinafine.
- TABLE 2.
In vitro interaction between voriconazole and terbinafine against S. prolificans
Method and strain Result according to theory LA BIa Nonparametric [median (range)] Parametricb (α ± 95% CI) Nonparametric Semiparametricc FICi-2 FICi-1 ΣSYN (n) ΣANT (n) ΣSYN (n) ΣANT (n) SP48 7898 0.13 (0.07-0.19) 0.10 (0.06-0.28) 13.9 ± 1.6 700 (29) 0 (0) 1,118 (51) 0 (0) 7901 0.25 (0.08-0.75) 0.10 (0.05-0.13) 10.8 ± 1.8 428 (29) 0 (0) 742 (48) 0 (0) 7906 0.26 (0.13-0.38) 0.13 (0.06-0.25) 16.3 ± 4.5 457 (26) 0 (0) 566 (36) 0 (0) 7918 0.09 (0.04-0.13) 0.09 (0.04-0.09) 2,479.8 ± 289.1 409 (21) 0 (0) 702 (39) 0 (0) 7902 0.14 (0.05-0.27) 0.09 (0.06-0.13) 42.2 ± 7.3 709 (44) 0 (0) 987 (53) 0 (0) Median 0.14 0.10 16.30 457 0 742 0 SP72 7898 0.07 (0.05-0.31) 0.14 (0.13-0.75) 13.0 ± 3.4 1,582 (49) 0 (0) 942 (42) 0 (0) 7901 0.32 (0.04-0.75) 0.13 (0.07-0.25) 32.4 ± 6.0 195 (14) −3 (1) 702 (43) 0 (0) 7906 0.38 (0.13-0.50) 0.28 (0.19-0.38) 8.4 ± 3.3 57 (8) 0 (0) 67 (4) 0 (0) 7918 0.08 (0.02-0.28) 0.27 (0.16-0.50) 1,517.5 ± 334.8 770 (29) −9 (2) 520 (21) −12 (1) 7902 0.29 (0.13-0.31) 0.19 (0.08-0.25) 6.6 ± 2.1 185 (15) 0 (0) 579 (41) −10 (2) Median 0.29 0.19 14.04 195 0 579 0 COL72 7898 0.25 (0.02-0.63) 0.13 (0.04-0.16) 8.9 ± 4.0 165 (10) 0 (0) 442 (20) 0 (0) 7901 0.75 (0.50-1.00) 0.16 (0.13-0.16) 29.9 ± 16.8 0 (0) 0 (0) 23 (4) 0 (0) 7906 0.53 (0.07-0.75) 0.17 (0.07-0.19) 8.0 ± 3.0 34 (4) 0 (0) 72 (7) 0 (0) 7918 0.13 (0.08-0.25) 0.20 (0.04-0.31) 40.7 ± 16.5 254 (8) 0 (0) 49 (3) 0 (0) 7902 0.16 (0.08-0.50) 0.11 (0.04-0.19) 42.0 ± 12.2 619 (22) 0 (0) 903 (32) 0 (0) Median 0.25 0.16 29.90 165 0 72 0 mCOL48 7898 0.25 (0.25-0.26) 0.25 (0.25-0.50) 1,754.9 ± 947.1 299 (15) −4 (1) 373 (19) −5 (2) 7901 0.25 (0.25) 0.25 (0.19-0.25) 33.7 ± 11.5 413 (25) −5 (2) 564 (34) 0 (0) 7906 0.25 (0.25) 0.27 (0.25-0.38) 2.7 ± 1.5 532 (35) 0 (0) 753 (40) 0 (0) 7918 0.25 (0.25-0.26) 0.13 (0.13-0.25) 9.9 ± 4.1 214 (10) 0 (0) 75 (5) 0 (0) 7902 0.26 (0.25-0.50) 0.27 (0.13-0.38) 8.2 ± 2.5 72 (5) 0 (0) 236 (11) 0 (0) Median 0.25 0.25 9.9 299 0 373 0 (0) mCOL72 7898 0.13 (0.08-0.13) 0.07 (0.06-0.07) 10.3 ± 7.6 279 (6) 0 (0) 56 (3) 0 (0) 7901 0.25 (0.09-0.38) 0.13 (0.07-0.13) 5.0 ± 2.6 795 (16) 0 (0) 379 (8) 0 (0) 7906 0.31 (0.13-0.31) 0.13 (0.06-0.13) 3.9 ± 2.4 566 (180) 0 (0) 1,072 (26) 0 (0) 7918 0.13 (0.07-0.13) 0.14 (0.07-0.14) 4.7 ± 2.9 579 (11) 0 (0) 513 (11) 0 (0) 7902 0.13 (0.07-0.25) 0.09 (0.06-0.13) 14.8 ± 5.0 464 (9) 0 (0) 468 (10) 0 (0) Median 0.13 0.13 5.0 566 0 468 0 ↵a The median absolute coefficient of variation of the differences between observed and predicted percent growth at each drug combination among the replicates of all strains ranged from 41 to 232% (median, 57%) for the SP method, 68 to 166% (median, 123%) for the COL method, and 44 to 83% (median, 53%) for the mCOL method with the semiparametric approach and from 49 to 165% (median, 88%) for the SP method, 86 to 180% (median, 105%) for the COL method, and 45 to 64% (median 51%) for the mCOL method with the nonparametric approach.
↵b The R2 from the nonlinear regression analysis for the fully parametric Greco model ranged from 0.83 to 0.96 (median, 0.90). The IC50s ranged from 0.96 to 2342 mg/liter (geometric mean, 5.9 mg/liter) of terbinafine and from 1.2 to 25 mg/liter (geometric mean, 4.2 mg/liter) of voriconazole. The slope (m) ranged from −0.16 to −1.46 (median, −0.61) for terbinafine and from −0.45 to −1.79 (median, −0.94) for voriconazole.
↵c The R2 from the nonlinear regression analysis for the Emax model of the semiparametric approach ranged from 0.74 to 0.99 (median, 0.90). The IC50s ranged from 1.6 to 67.4 mg/liter (geometric mean, 10.6 mg/liter) of terbinafine and from 0.24 to 16.7 mg/liter (geometric mean, 2.9 mg/liter) of voriconazole. The slopes m ranged from −0.44 to −4.38 (median, −0.92) for terbinafine and from −0.13 to −5.2 (median, −1.2) for voriconazole.
- TABLE 3.
In vitro interaction between miconazole and terbinafine against S. prolificans
Method and strain Result according to theory LA BIa Nonparametric [median (range)] Parametricb (α ± 95% CI) Nonparametric Semiparametricc FICi-2 FICi-1 ΣSYN (n) ΣANT (n) ΣSYN (n) ΣANT (n) SP48 7898 0.13 (0.02-0.28) 0.04 (0.01-0.05) 302.1 ± 32.6 173 (15) 0 (0) 242 (17) 0 (0) 7901 0.11 (0.02-0.14) 0.05 (0.02-0.06) 3,072.0 ± 441.7 243 (15) 0 (0) 396 (22) 0 (0) 7902 0.17 (0.14-0.28) 0.08 (0.01-0.28) 111.1 ± 17.5 163 (20) 0 (0) 206 (22) −4 (1) 7906 0.17 (0.09-0.28) 0.04 (0.01-0.13) 565.0 ± 110.7 160 (11) 0 (0) 284 (18) 0 (0) 7918 0.06 (0.03-0.15) 0.03 (0.02-0.08) 9,462.1 ± 1,194.5 460 (33) 0 (0) 615 (40) 0 (0) Median 0.13 0.04 565.0 178 0 284 0 SP72 7898 0.06 (0.02-0.09) 0.05 (0.03-0.08) 552.1 ± 77.6 57 (5) 0 (0) 135 (13) 0 (0) 7901 0.05 (0.02-0.08) 0.05 (0.03-0.06) 5,516.6 ± 966.9 146 (10) 0 (0) 365 (21) 0 (0) 7902 0.06 (0.03-0.28) 0.06 (0.03-0.14) 1,374.9 ± 242.9 10 (2) 0 (0) 78 (8) −6 (1) 7906 0.09 (0.03-0.13) 0.05 (0.02-0.07) 434.5 ± 124.9 67 (4) 0 (0) 138 (11) 0 (0) 7918 0.06 (0.03-0.16) 0.05 (0.03-0.27) 5,464.7 ± 1,082.9 392 (27) 0 (0) 505 (33) 0 (0) Median 0.06 0.05 1,374.9 67 0 138 0 COL72 7898 0.06 (0.03-0.09) 0.04 (0.02-0.06) 817.5 ± 297.5 7 (1) 0 (0) 14 (1) 0 (0) 7901 0.19 (0.06-0.28) 0.03 (0.02-0.04) 180.1 ± 50.3 17 (3) 0 (0) 92 (11) −25 (2) 7902 0.05 (0.02-0.08) 0.05 (0.02-0.08) 128.2 ± 28.4 8 (1) 0 (0) 0 (0) 0 (0) 7906 0.03 0.05 (0.03-0.16) 55.5 ± 23.8 0 (0) 0 (0) 0 (0) 0 (0) 7918 0.08 (0.03-0.19) 0.04 (0.02-0.09) 633.2 ± 162.2 57 (3) 0 (0) 0 (0) 0 (0) Median 0.06 0.04 180.1 8 0 0 0 MCOL48 7898 0.27 (0.27-0.28) 0.05 (0.04-0.13) 9.8 ± 2.2 556 (49) 0 (0) 567 (43) −6 (1) 7901 0.16 (0.09-0.31) 0.05 (0.04-0.05) 44.3 ± 11.4 955 (55) 0 (0) 941 (49) 0 (0) 7902 0.27 (0.27-0.50) 0.04 (0.03-0.05) 34.1 ± 8.2 354 (41) 0 (0) 392 (35) 0 (0) 7906 0.38 (0.31-0.51) 0.04 (0.04-0.05) 18.5 ± 5.0 539 (35) 0 (0) 526 (37) 0 (0) 7918 0.27 (0.13-0.28) 0.31 (0.05-0.31) 3,807.5 ± 1,479.4 259 (32) 0 (0) 372 (33) 0 (0) Median 0.27 0.05 34.1 539 0 526 0 MCOL72 7898 0.03 (0.03-0.04) 0.06 (0.06-0.13) 9,505.2 ± 2,824.2 487 (30) 0 (0) 518 (28) −9 (1) 7901 0.03 (0.02-0.04) 0.09 (0.06-0.09) 6,768.1 ± 2,078.9 1,051 (37) 0 (0) 1,006 (36) 0 (1) 7902 0.03 (0.02-0.03) 0.06 (0.06-0.13) 7,740.3 ± 1,887.3 1,751 (61) 0 (0) 1,295 (46) 0 (0) 7906 0.03 (0.02-0.04) 0.13 (0.06-0.13) 7,872.5 ± 3,421.3 606 (39) 0 (0) 517 (38) 0 (0) 7918 0.06 (0.03-0.09) 0.08 (0.06-0.08) 534.6 ± 141.8 595 (45) 0 (0) 538 (34) 0 (0) Median 0.03 0.08 7,740.3 606 0 538 0 ↵a The median absolute coefficient of variation of the differences between observed and predicted percent growth at each drug combination among the replicates of all strains ranged from 60 to 124% (median, 95%) for the SP method, 142 to 227% (median, 173%) for the COL method, and 24 to 49% (median, 40%) for the mCOL method with the semiparametric approach and from 69 to 191% (median, 123%) for the SP method, 118 to 343% (median, 236%) for the COL method, and 23 to 56% (median, 36%) for the mCOL method with the nonparametric approach.
↵b The R2 from the nonlinear regression analysis for the fully parametric Greco model ranged from 0.76 to 0.93 (median, 0.88). The IC50s ranged from 0.23 × 103 to −7.2 × 103 mg/liter (geometric mean, 22.1 mg/liter) of terbinafine and from 0.53 to 32.9 mg/liter (geometric mean, 4.2 mg/liter) of miconazole. Relatively high IC50s of terbinafine were obtained after 72 h of incubation. The slope (m) ranged from −0.1 to −0.53 (median, −0.16) for terbinafine and from −0.27 to −4.4 (median, −0.44) for miconazole.
↵c The R2 from the nonlinear regression analysis for the Emax model of the semiparametric approach ranged from 0.73 to 0.99 (median, 0.88). The IC50s ranged from 0.57 to 1,028 mg/liter (geometric mean, 11.4 mg/liter) of terbinafine and from 0.19 to 43.74 mg/liter (geometric mean, 4.43 mg/liter) of miconazole. The slope (m) ranged from −0.10 to −0.86 (median, −0.35) for terbinafine and from −0.24 to −1.63 (median, −0.45) for miconazole.
- TABLE 4.
In vitro interaction between itraconazole and terbinafine against S. prolificans
Method and strain Result according to theory LA BIa Nonparametric [median (range)] Parametricb (α ± 95% CI) Nonparametric Semiparametricc FICi-2 FICi-1 ΣSYN (n) ΣANT (n) ΣSYN (n) ΣANT (n) SP48 7898 0.13 (0.07-0.16) 0.19 (0.13-0.19) 4.3 ± 1.3 19 (2) −20 (1) 244 (18) −45 (3) 7901 0.52 (0.51-0.52) 0.13 (0.13-0.19) 9.3 ± 1.8 36 (3) −25 (2) 90 (15) −27 (2) 7902 0.07 (0.02-0.56) 0.13 (0.13-0.25) 203.8 ± 49.1 49 (4) 0 (0) 144 (8) 0 (0) 7906 0.16 (0.04-0.51) 0.14 (0.13-0.19) 3.3 ± 0.8 230 (14) 0 (0) 291 (16) 0 (0) 7918 0.51 (0.07-0.51) 0.13 (0.09-0.38) 25.1 ± 9.6 52 (5) 0 (0) 167 (11) 0 (0) Median 0.16 0.13 9.3 49 0 167 0 SP72 7898 0.13 (0.07-0.56) 0.14 (0.13-0.16) 25.9 ± 8.2 76 (6) −31 (2) 202 (16) −178 (11) 7901 0.75 (0.52-1.00) 0.31 (0.31-0.38) 57.2 ± 14.7 10 (1) −85 (4) 7 (1) −98 (4) 7902 0.02 (0.02-0.28) 0.19 (0.07-0.38) 182.9 ± 48.1 41 (4) 0 (0) 90 (7) 0 (0) 7906 0.13 (0.06-0.38) 0.16 (0.14-0.27) 8.1 ± 2.5 536 (26) 0 (0) 428 (23) 0 (0) 7918 0.51 (0.06-0.52) 0.14 (0.09-0.38) 457.6 ± 148.5 81 (8) 0 (0) 180 (17) 0 (0) Median 0.13 0.16 57.2 76 0 180 0 COL72 7898 0.07 (0.02-0.26) 0.16 (0.09-0.16) 202.9 ± 130.7 0 (0) −46 (40) 0 (0) −109 (8) 7901 0.13 (0.01-0.16) 0.26 (0.25-0.27) 5.2 ± 3.3 7 (1) −83 (8) 0 (0) 0 (0) 7902 0.13 (0.01-1.02) 0.19 (0.14-0.25) 29.1 ± 20.5 10 (1) −53 (4) 179 (11) −3 (1) 7906 0.04 (0.02-0.13) 0.13 (0.09-0.25) 23.7 ± 13.7 6 (1) −209 (26) 16 (3) −404 (13) 7918 0.16 (0.08-0.26) 0.16 (0.13-0.16) 69.9 ± 59.7 380 (12) 0 (0) 384 (15) −4 (1) Median 0.13 0.16 29.1 7 −53 16 −4 MCOL48 7898 0.34 (0.19-0.50) 0.27 (0.27-0.28) 105.4 ± 39.1 25 (5) −1 (1) 69 (8) 0 (0) 7901 0.14 (0.13-0.15) 0.20 (0.14-0.26) 802.1 ± 310.8 276 (22) 0 (0) 417 (20) 0 (0) 7902 0.27 (0.25-0.28) 0.20 (0.16-0.25) 23.9 ± 9.4 105 (12) 0 (0) 209 (20) −0 (0) 7906 0.20 (0.16-0.25) 0.23 (0.19-0.27) 81.6 ± 28.0 31 (4) 0 (0) 88 (6) 0 (0) 7918 0.11 (0.06-0.16) 0.08 (0.02-0.14) 795.3 ± 435.9 79 (5) 0 (0) 49 (2) 0 (0) Median 0.20 0.20 105.4 79 0 88 0 MCOL72 7898 0.21 (0.14-0.28) 0.18 (0.04-0.31) 959.7 ± 542.4 146 (5) 0 (0) 529 (18) 0 (0) 7901 0.04 (0.02-0.07) 0.15 (0.05-0.25) 5,091.5 ± 3,287.1 942 (31) 0 (0) 372 (15) 0 (0) 7902 0.30 (0.28-0.31) 0.05 (0.04-0.06) 404.7 ± 242.3 533 (22) 0 (0) 616 (23) −5 (10) 7906 0.28 (0.25-0.31) 0.06 (0.05-0.07) 2,351.3 ± 1,445.1 83 (5) 0 (0) 300 (19) 0 (0) 7918 0.04 (0.03-0.05) 0.07 (0.05-0.09) 7,673.7 ± 389.4 263 (10) 0 (0) 1,354 (44) 0 (0) Median 0.21 0.07 959.7 263 0 529 −16 ↵a The median absolute coefficient of variation of the differences between observed and predicted percent growth at each drug combination among replicates of all strains ranged from 58 to 157% (median, 106%) for the SP method, 59 to 222% (median, 106%) for the COL method, and 51 to 69% (median, 61%) for mCOL method with the semiparametric approach and from 57 to 287% (median, 154%) for the SP method, 51 to 195% (median, 115%) for the COL method, and 58 to 89% (median, 71%) for the mCOL method with the non-parametric approach.
↵b The R2 from the nonlinear regression analysis for the fully parametric Greco model ranged from 0.69 to 0.95 (median, 0.88). The IC50s ranged from 0.15 to 93.6 mg/liter (geometric mean, 2.98 mg/liter) of terbinafine and 17.5 × 103 to 7 × 103 mg/liter (geometric mean, 404.4 mg/liter) of itraconazole. The slope (m) ranged from −0.15 to −1.7 (median, −0.68) for terbinafine and −0.16 to −26.7 (median, −0.28) for itraconazole.
↵c The R2 from the nonlinear regression analysis for the Emax model of the semiparametric approach ranged from 0.77 to 0.99 (median, 0.95). The IC50s ranged from 0.23 to 155 mg/liter of terbinafine (geometric mean, 2.85 mg/liter) and from 5.2 to 5011 mg/liter of itraconazole (geometric mean, 298.64 mg/liter). The slope (m) ranged from −0.11 to −1.22 (median, −0.52) for terbinafine and −0.06 to −0.99 (median, −0.43) for itraconazole.
