Fluconazole-containing agar Sabouraud dextrose plates are not useful when screening for susceptibility in Candida albicans.
OBJECTIVE
Fluconazole is an alternative for candidemic patients who are not critically ill. Fluconazole is mainly fungistatic and does not completely inhibit visual Candida albicans growth. We studied the usefulness of fluconazole-containing Sabouraud dextrose agar plates for detecting susceptibility to fluconazole in C. albicans.


METHODS
Adjusted inocula of 19 isolates were transferred directly onto fluconazole-containing Sabouraud dextrose plates (concentrations ranging from 0.125 mg/L to 128 mg/L). The fluconazole MIC in fresh isolates and after growth on the fluconazole-containing plate at 128 mg/L was recorded following the EUCAST EDef 7.2 guidelines. Then isolates were classified according to their degree of trailing production, based on microdilution procedure.


RESULTS
All isolates were able to grow on all fluconazole-containing plates, even those isolates susceptible to fluconazole. In fact, we selected isolates with different degrees of trailing based on microdilution procedures. 50% of isolates classified as heavy trailers, 35.71% as moderate trailers, and 14.28% as slight trailers.


CONCLUSIONS
The use of fluconazole-containing Sabouraud dextrose agar plates was not a reliable method to detect fluconazole susceptibility in C. albicans isolates; growth of the isolates was a trailing effect rather than true resistance.
M A
MA
Bordallo-Cardona
L J
LJ
Marcos-Zambrano
E
E
Gómez G de la Pedrosa
P
P
Escribano
E
E
Bouza
Jesús Guinea, Servicio de Microbiología Clínica y Enfermedades Infecciosas Hospital General Universitario Gregorio Marañón, C/ Dr. Esquerdo, 46 - 28007 Madrid, Spain. jguineaortega@yahoo.es.
J
J
Guinea
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R
Cantón
D000362:Agar; D000935:Antifungal Agents / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects*; D002177:Candidiasis / Q000382:microbiology; D003470:Culture Media; D015725:Fluconazole / Q000494:pharmacology*; D005947:Glucose; D008826:Microbial Sensitivity Tests / Q000379:methods*; D015203:Reproducibility of Results
D000935:Antifungal Agents; D003470:Culture Media; D015725:Fluconazole; D000362:Agar; D005947:Glucose