In vitro susceptibility testing of amphotericin B for Cryptococcus neoformans variety grubii AFLP1/VNI and Cryptococcus gattii AFLP6/VGII by CLSI and flow cytometry

Mycoses. 2015 May;58(5):273-9. doi: 10.1111/myc.12310. Epub 2015 Mar 10.

Abstract

Cryptococcus neoformans var. grubii AFLP1/VNI is the main causative agent of cryptococcosis associated with AIDS in the world. Cryptococcus gattii AFLP6/VGII causes mainly endemic primary infection in immunocompetent hosts. To determine the minimum inhibitory concentrations (MICs) of C. neoformans var. grubii AFLP1/VNI and C. gattii AFLP6/VGII against amphotericin B (AMB) in a short period of time, flow cytometry (FCM) with FUN-1 fluorochrome was used to compare with broth microdilution method (CLSI M27-A3). The minimum incubation period was evaluated by minimum fungicidal concentration procedure. Seventeen clinical isolates of C. neoformans var. grubii AFLP1/VNI and 18 of C. gattii AFLP6/VGII were analysed. The time for the determination of MICs by FCM was 2 h against 72 h by CLSI M27-A3 and the comparison of MIC showed a positive significant correlation (P = 0.048). It is important to highlight the role of the FCM as an alternative method to determine the MICs for AMB in within a day, with positive cost-benefit.

Keywords: CLSI M27-A3; Cryptococcus gattii; Cryptococcus neoformans; amphotericin B; flow cytometry.

MeSH terms

  • Amphotericin B / pharmacology*
  • Antifungal Agents / pharmacology*
  • Colony Count, Microbial
  • Cryptococcus gattii / drug effects*
  • Cryptococcus neoformans / drug effects*
  • Flow Cytometry / methods*
  • Microbial Sensitivity Tests / economics

Substances

  • Antifungal Agents
  • Amphotericin B