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In vitro susceptibility of clinical isolates of Cryptococcus gattii

Abstract number: 1733_1466

Gomez-Lopez A., Bernal-Martinez L., Alastruey-Izquierdo A., Rodriguez-Tudela J., Cuenca-Estrella M.

Background: A recent outbreak of C. gattii infection of Vancouver Island (Canada) emphasize the role of this specie as causal agent of infections in temperate climate. In addition, Cryptococcus gattii has shown less in vitro susceptibility than C. neoformans to amphotericin B and flucytosine although contradictory results have been obtained in other studies. We have analysed the antifungal susceptibility profile of clinical isolates of C. neoformans var. gatti and compared with C. neoformans var. neoformans.

Methods: A collection of 20 isolates of C. neoformans var. gatti. was included in the study. Nineteen of the strains were obtained from colleagues. In addition, the in vitro susceptibility of 323 strain of C. neoformans var. neoformans received in our institution between 1995 and 2006 was evaluated.

The isolates were identified by routine physiological tests. The susceptibility testing followed strictly the recommendations proposed by the Antifungal Susceptibility testing Subcommittee of the European Committee on Antibiotic Susceptibility Testing for fermentative yeast. The antifungal agents used in the study were as follow: amphotericin B, flucytosine, fluconazole, itraconazole, voriconazole, ravuconazole, posaconazole and caspofungin.

Results: The table displays susceptibility results.

Antifungal agentC. neoformans var. gattii (n = 20)C. neoformans var. neoformans (n = 333)
GMMIC90MIC50GMMIC90MIC50 
Amphotericin B0.090.1250.1250.2410.25
Flucytosine1.07214.38164
Fluconazole14.9316167.44168
Itraconazole0.4510.50.2510.25
Voriconazole0.4710.50.120.50.125
Ravuconazole0.5320.50.1510.125
Posaconazole0.260.50.250.160.50.25
Caspofungin16161618.023216

Conclusions: (i) C. gattii was less susceptible in vitro to amphotericin B and fluocytosine than C. neoformans (p < 0.01). (ii) C. gattii showed significantly higher MICs to azole agents (p < 0.01). (iii) Both species seems intrinsically resistant to caspofungin (GM ≥ 16 mg/mL).

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Subject:
Location: ICC, Munich, Germany
Presentation type:
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