TABLE 3.
Growth promotion of Candida species by different hydroxamate siderophores and susceptibility to siderophore-drug conjugates
| Siderophore preference and strain | Growtha of Candida species on:
|
MICb (μM) in iron-rich medium/iron-low medium (ratio) of compound:
|
|||||||
|---|---|---|---|---|---|---|---|---|---|
| FCH | FOB | ORNI | ISO | RHO | DE | DE-mono | DE-tri | DE-iso | |
| Most hydroxamates | |||||||||
| Calb1 | ++++ | − | − | +++ | − | 0.8/0.2 (4) | 50/3.1 (16) | 25/12.5 (2) | 200/25 (8) |
| Calb2 | ++++ | − | +++ | + | − | 0.8/0.4 (2) | 6.25/1.6 (4) | 25/12.5 (2) | 200/50 (4) |
| C. pseudotropicalis | − | ++++ | +++ | − | − | 1.6/1.6 (1) | 12.5/6.25 (2) | 50/25 (2) | 200/25 (8) |
| C. stellatoidea | + | − | ++ | − | − | 0.8/0.4 (2) | 12.5/6.25 (2) | 50/25 (2) | 200/50 (4) |
| Isocyanurate-based hydroxamate | |||||||||
| C. krusei | − | − | − | ++ | − | 0.2/0.2 (1) | 3.1/3.1 (1) | 25/25 (1) | >200/100 (≥4) |
| C. parapsilosis | − | − | − | ++ | − | 0.2/0.1 (2) | 1.6/1.6 (1) | 12.5/12.5 (1) | 100/50 (2) |
| C. guilliermondii | − | − | + | + | − | 6.25/3.1 (2) | 25/25 (1) | 50/50 (1) | >200/200 (≥2) |
a
Relative growth in the presence of siderophore (25 μM for ferrichrome [FCH], ferrioxamine B [FOB], and omithine-based trihydroxamate [ORNI] or 200 μM for isocyanurate-based hydroxamate [ISO] and rhodotorulic acid [RHO]) in YPD broth supplemented with 2,2′-dipyridyl compared to growth in YPD broth. −, 0 to 20%; +, 21 to 40%; ++, 41 to 60%; +++, 61 to 80%; ++++, 81 to 100%.
b
MIC determined in YPD broth (iron-rich medium, first value) and in YPD broth supplemented with 0.15 mM 2,2′-dipyridyl or 0.20 mM for C. pseudotropicalis (iron-low medium, second value).