Comparison of broth dilution and semisolid agar dilution for in vitro susceptibility testing of Cryptococcus neoformans.
We compared the in vitro activity of amphotericin B, flucytosine, itraconazole, fluconazole, ketoconazole and miconazole against 18 strains of Cryptococcus neoformans by using two methods: microbroth dilution and semisolid agar dilution. By both of the methods minimum inhibitory concentrations (MICs) showed a wide range for all antifungal agents but not for amphotericin B. Statistically significant differences between the two methods were observed only with amphotericin B and flucytosine, p = 0.048 and p = 0.045 respectively. Our study suggests that azole susceptibility testing for C. neoformans may be performed by the broth microdilution as well as the semisolid agar test. The choice of the method when testing amphotericin B and flucytosine is more problematic.
Del Poeta
M
M
Institute of Infectious Diseases and Public Health, University of Ancona, Ospedale Umberto I., Italy.
Barchiesi
F
F
Morbiducci
V
V
Arzeni
D
D
Marinucci
G
G
Ancarani
F
F
Scalise
G
G
D000666:Amphotericin B / Q000494:pharmacology; D000935:Antifungal Agents / Q000494:pharmacology*; D001769:Blood / Q000382:microbiology; D002555:Cerebrospinal Fluid / Q000382:microbiology; D003455:Cryptococcus neoformans / Q000187:drug effects* / Q000302:isolation & purification; D015725:Fluconazole / Q000494:pharmacology; D005437:Flucytosine / Q000494:pharmacology; D006801:Humans; D017964:Itraconazole / Q000494:pharmacology; D007654:Ketoconazole / Q000494:pharmacology; D008825:Miconazole / Q000494:pharmacology; D008826:Microbial Sensitivity Tests / Q000379:methods; D012867:Skin / Q000382:microbiology
D000935:Antifungal Agents; D017964:Itraconazole; D008825:Miconazole; D000666:Amphotericin B; D015725:Fluconazole; D005437:Flucytosine; D007654:Ketoconazole