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In vitro susceptibility testing of fungal isolates from immunosuppressed, organ-transplanted patients for anidulafungin and azoles

Abstract number: P2171

Antoniewicz L., Poitschek C., Willinger B., Geusau A.

Objectives: Organ transplant recipients (OTR) are predisposed to mucocutaneous Candida infections. The aim of our study was to compare the minimum inhibitory concentration (MIC) of the newly introduced drug anidulafungin, an echinocandin, and already marked azoles (flu-, itra-, vori-, posaconazole) in strains obtained from this particular risk group in comparison to healthy controls.

Methods: From 400 OTR and 405 sex- and age-matched controls, two body sites were sampled for fungal culture (oral and genital mucosa/glans penis). Susceptibility testing was carried out in parallel for the azoles using the E-test (AB Biodisk, Sona Sweden). Results were read after 24 hours (MIC 80). For anidulafungin MIC (90) was obtained by broth microdilution method according to CLSI standard and determined visually and by spectophotometry after 48 h.

Results: From 529 isolates (273 from OTR, 256 from controls) susceptibility tests were carried out (418 oral mucosa, 111 genital area/mucosa). The number of Candida non-albicans species was significantly increased in OTR in the late post-transplantation period (>18 months) compared to the early period and the controls. For fluconazole, 2.2% (n = 1) of C. glabrata were resistant (MIC geqslant R: gt-or-equal, slanted 64ug/ml), for itraconazole, 82.6% (n = 38) of C. glabrata, 66.7% (n = 2) of C. krusei (MIC geqslant R: gt-or-equal, slanted 1ug/ml); all strains were susceptible for voriconazole (MIC leqslant R: less-than-or-eq, slant 1ug/ml). For posaconazole and anidulafungin no reference values for break points exist. For posaconazole, 10.9% (n = 5) of C. glabrata showed a MIC (80) geqslant R: gt-or-equal, slanted4ug/ml (all other strains range 0.002–0.38 ug/ml). C. albicans, C. glabrata, C. tropicalis, C. krusei, C. lusitaniae, C. norvegensis were most susceptible for anidulafungin (MIC (90), 0.03 to 0.25 ug/ml); C. parapsilosis and C. dubliniensis were the least susceptible (MIC (90), 0.25 to 16 ug/ml). C. guilliermondii was neither isolated from OTR nor from controls. With regard to in vitro activity there was no difference between strains from OTR and controls, no shift towards decreased susceptibility of the Candida strains obtained in the late post-transplantation period or with the type of organ transplanted.

Conclusion: With the exception of C. glabrata, Candida spp. obtained from OTR exhibit very good in vitro activity towards azoles. With regard to anidulafungin all Candida strains from these patients including C. glabrata showed an excellent in vitro activity with the exception of C. parapsilosis and C. dubliniensis showing higher MICs than other Candida spp.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Barcelona, Spain
Presentation type:
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