Results obtained with various antifungal susceptibility testing methods do not predict early clinical outcome in patients with cryptococcosis

Antimicrob Agents Chemother. 2006 Jul;50(7):2464-70. doi: 10.1128/AAC.01520-05.

Abstract

The in vitro susceptibilities of Cryptococcus neoformans isolates from consecutive human immunodeficiency virus-positive and -negative patients to the antifungal agents fluconazole, amphotericin B, and flucytosine were determined by different techniques, including the CLSI method, Etest, and broth microdilution in yeast nitrogen base (YNB) medium, during a multicenter prospective study in France. The relationship between the in vitro data and the clinical outcome 2 weeks after the initiation of antifungal therapy was assessed. In addition, the correlation between the strain serotype and the in vitro activities of the antifungals was determined, and the susceptibility results obtained with the different techniques were also compared. Thirty-seven patients received a combination of amphotericin B with flucytosine as first-line therapy, 22 were treated with amphotericin B alone, and 15 received fluconazole alone. Whatever the antifungal tested, there was no trend toward higher MICs for strains isolated from patients who failed to respond to a given therapy compared to those from patients who did not with either the CLSI method, Etest, or broth microdilution in YNB medium. The MICs obtained by the CLSI or Etest method were significantly lower for serotype D strains than for serotype A strains for both fluconazole and amphotericin B, while flucytosine MICs were not different according to serotype. These findings suggest that the in vitro antifungal susceptibility of C. neoformans, as determined with the techniques used, is not able to predict the early clinical outcome in patients with cryptococcosis.

Publication types

  • Multicenter Study

MeSH terms

  • AIDS-Related Opportunistic Infections / drug therapy
  • AIDS-Related Opportunistic Infections / microbiology
  • Amphotericin B / pharmacology
  • Amphotericin B / therapeutic use
  • Antifungal Agents / pharmacology*
  • Antifungal Agents / therapeutic use
  • Cryptococcosis / complications
  • Cryptococcosis / drug therapy*
  • Cryptococcosis / microbiology
  • Cryptococcus neoformans / drug effects
  • Female
  • Fluconazole / pharmacology
  • Fluconazole / therapeutic use
  • Flucytosine / pharmacology
  • Flucytosine / therapeutic use
  • HIV Infections / complications
  • Humans
  • Male
  • Microbial Sensitivity Tests / methods
  • Predictive Value of Tests
  • Prognosis
  • Treatment Outcome

Substances

  • Antifungal Agents
  • Amphotericin B
  • Fluconazole
  • Flucytosine