Article Figures & Data
Figures
- FIG. 1.
Percentages of metabolic activity of three clinical isolates of A. fumigatus (F2, F3, and F4) at the stage of nongerminated conidia (A) and filamentous forms (B) detected by XTT assay. AFG (white bars), AMB (striped bars), and the combination of the two antifungal agents (black bars) were tested to concentrations of 1/4, 1, and 4 times the respective MICs and MECs. The bars represent the means of percent metabolic activity in the presence of the drugs with respect to the growth controls. The error bars indicate the standard deviations of the means. Letters a and b indicate reduced metabolic activity of the combination versus AFG and AMB alone, respectively (P < 0.05). Each strain was tested in triplicate.
- FIG. 2.
Survival of mice infected intravenously with the A. fumigatus F3 clinical isolate. In study 1, the animals were infected with 1.5 × 107 conidia/mouse and treated with AMB at 1 mg/kg/day, AFG at 1 mg/kg/day, and the respective combination regimen; in study 2, the mice were infected with 3.5 × 105 conidia/mouse and treated with AMB at 1 mg/kg/day, AFG at 1 mg/kg/day, and the respective combination; in study 3, the animals were infected with 3.2 × 106A. fumigatus conidia/mouse and treated with AMB at 0.5 mg/kg/day, AFG at 5 mg/kg/day, and the corresponding combination. The therapies were started 2 h postinfection (day 0) and continued through day 4 postinfection (five consecutive days). There were from 9 to 16 mice in each group. Asterisks indicate groups with prolonged survival over controls (due to multiple comparisons, P values of <0.016 were considered statistically significant).
- FIG. 3.
Histopathological sections of kidney and brain tissues stained with Grocott Gomori (original magnification, ×25) from mice infected with 3.2 × 106 conidia of the A. fumigatus F3 isolate. Representative histopathological sections of kidney and brain tissues from control mice (C) and from mice treated for three consecutive days with AMB at 0.5 mg/kg/day and AFG at 5 mg/kg/day are shown.
Tables
- TABLE 1.
In vitro susceptibility tests of AFG and AMB, alone and in combination, against three clinical isolates of A. fumigatusa
Isolate Drug(s) MIC or MEC (μg/ml) at 24 h MIC or MEC (μg/ml) at 48 h MFC (μg/ml) at 48 h Median Range Median Range Median Range F2 AFG 0.001 0.001-0.002 0.002 0.002 >16 >16 AMB 0.5 0.25-0.5 1.0 1.0 1.0 1.0-2.0 AFG + AMBb 0.001/0.03 0.001-0.002/0.03-0.06 0.001/0.06 0.001-0.002/0.03-0.06 <0.0002/1.0 <0.0002/1.0-2.0 F3 AFG 0.001 0.001-0.002 0.002 0.002 >16 >16 AMB 0.25 0.25-0.5 1.0 0.5-1.0 1.0 0.5-1.0 AFG + AMBb 0.001/0.03 0.001/0.03 0.002/0.03 0.002-0.03 <0.0002/1.0 <0.0002/0.5-1.0 F4 AFG 0.002 0.001-0.002 0.002 0.002 >16 >16 AMB 0.25 0.125-0.5 1.0 1.0-2.0 1.0 0.5-1.0 AFG + AMBb 0.002/0.25 0.001-0.002/0.03-0.25 0.002/0.25 0.001-0.002/0.25 <0.0002/1.0 <0.0002/0.5-1.0 ↵ a Each test was run in triplicate and repeated on two different days.
↵ b The MEC values were reported as end point readings of the checkerboard assays. The interaction between the drugs was classified as “indifferent” in each case (interactions were defined as synergistic if the FIC index was less than or equal to 0.50, indifferent if the FIC index was greater than 0.50 and less than or equal to 4.0, and antagonistic if the FIC index was greater than 4.0).
- TABLE 2.
Fungal burden in tissues of A. fumigatus-infected mice measured by CFU and quantitative PCR assaysa
Challenge dose (conidia/mouse) Treatment (drug, dose [mg/kg/day]) Brain burden Kidney burden Mean log10 CFU/g of tissue ± SD Mean log10 CE/g of tissue ± SD Mean log10 CFU/g of tissue ± SD Mean log10 CE/g of tissue ± SD 3.5 × 105 Control 3.17 ± 0.44 4.49 ± 0.35 5.12 ± 0.26 7.85 ± 0.57 AMB, 1 2.51 ± 0.74 3.73 ± 0.81 4.74 ± 0.43 7.17 ± 0.64 AFG, 1 3.02 ± 0.83 4.50 ± 1.09 4.95 ± 0.27 7.42 ± 0.59 AMB, 1 + AFG, 1 3.06 ± 0.60 4.78 ± 0.47 4.89 ± 0.44 7.78 ± 0.53 3.2 × 106 Control 3.73 ± 0.25 5.60 ± 0.36 5.31 ± 0.15 7.68 ± 0.22 AMB, 0.5 3.82 ± 0.22 5.88 ± 0.71 4.96 ± 0.32 7.36 ± 0.34 AFG, 5 4.08 ± 0.40 6.27 ± 0.65 4.60 ± 0.50* 6.61 ± 0.66* AMB, 0.5 + AFG, 5 4.16 ± 0.71 6.58 ± 0.98 4.24 ± 0.39* 6.50 ± 0.62* ↵ a The animals were infected with the A. fumigatus F3 isolate (3.5 × 105 conidia/mouse and 3.2 × 106 conidia/mouse in studies 2 and 3, respectively) and euthanized 3 days later. There were seven animals per group, and fungal burdens of brains and kidneys were determined by measuring CFU or conidial equivalents (CE) per gram of tissue. Asterisks indicate treatment groups with reduced fungal burdens over the controls (due to multiple comparisons, P values of <0.016 were considered statistically significant).
