Comparison between disk diffusion and microdilution methods for determining susceptibility of clinical fungal isolates to caspofungin.
We compared the caspofungin (CAS) susceptibility testing results generated by the disk diffusion (DD) assay with the results of the Clinical and Laboratory Standards Institute (CLSI) broth microdilution (BD) reference method for 106 yeast isolates. The isolates represented 11 different fungal species, including Candida albicans (n = 50), C. parapsilosis (n = 10), C. glabrata (n = 10), C. tropicalis (n = 10), C. guillermondii (n = 6), C. rugosa (n = 5), C. krusei (n = 5), C. kefyr (n = 2), C. pelliculosa (n = 2), Saccharomyces cerevisiae (n = 3), and Geotrichum candidum (n = 3). The DD assay was performed in supplemented Mueller-Hinton agar with CAS, which was tested at concentrations of 2, 10, and 25 mug per disk. MICs and inhibition zone diameters were evaluated at 24 and 48 h. In general, the results obtained by the DD assay correlated well with those obtained by the BD method. In particular, a significant correlation between methods was observed when CAS was used at concentration of 2 mug/disk at a reading time of either 24 or 48 h.
Milici
Maria Eleonora
ME
Dipartimento di Igiene e Microbioogia D'Alessandro, Università degli Studi di Palermo, Palermo, Italy.
Maida
Carmelo Massimo
CM
Spreghini
Elisabetta
E
Ravazzolo
Barbara
B
Oliveri
Salvatore
S
Scalise
Giorgio
G
Barchiesi
Francesco
F
D000935:Antifungal Agents / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects; D000077336:Caspofungin; D004058:Diffusion; D054714:Echinocandins / Q000494:pharmacology*; D005658:Fungi / Q000187:drug effects*; D055666:Lipopeptides; D008826:Microbial Sensitivity Tests / Q000379:methods*
D000935:Antifungal Agents; D054714:Echinocandins; D055666:Lipopeptides; D000077336:Caspofungin