Thermokinetic Evaluation of Fluconazole, Caspofungin, Anidulafungin and Amphotericin B on Planktonic and Biofilm Candida spp. by Microcalorimetry

Ref ID: 18767

Author:

E. Maiolo, PhD – PhD1, F. Ulrika, PhD – PhD 1, S. Dominique, Professor – Professor 2, T. Andrej, MD – MD 1;

Author address:

1Univ. Hosp., Lausanne, Switzerland, 2Institue of microbiology, Lausanne, Switzerland.

Full conference title:

52nd Annual ICAAC

Date: 9 September 2014

Abstract:

Objectives: Candida biofilms are difficult to treat due to reduced susceptibility in biofilm. We compared the activity of FZL, AMB and two echinocandins, CAS and AFG, against planktonic and biofilm Candida spp. with microcalorimetry. Methods: C. albicans (ATCC 90028), C. krusei (ATCC 6258), C. parapsilosis (ATCC 22019) and C. glabrata (DSY 562) were tested. MIC was determined by microbroth dilution. Planktonic Candida species (5×10^5 CFU) were added to RPMI containing serial drug dilutions (0.015-512 μg/ml). Candida biofilm was formed on glass beads for 24 h at 37°C in RPMI. Beads were incubated for 24 h with serial drug dilutions, washed and introduced in RPMI in the calorimeter. The minimal heat inhibitory concentration (MHIC) was defined as the lowest antifungal concentration reducing the heat-flow peak by ≥ 50%. Results: Table shows the MHICs for planktonic and biofilm Candida (µg/ml). The MICs for tested Candida spp. were 0.25-32 µg/ml for FZL, 0.125/0.5 µg/ml for CAS, 0.03-0.125 µg/ml for AFG and 0.5-2 µg/ml for AMB. The activity of FLC was reduced by >1000-fold in Candida biofilms compared to planktonic counterparts. FLC induced growth of planktonic C. krusei at sub-MIC concentrations whereas CAS and AFG, at high concentrations (>8 µg/ml), induced paradoxical growth of planktonic C. albicans. CAS preserved its antibiofilm activity against C. albicans and C. glabrata, but not against C. krusei. The activity of AMPB was reduced in C. albicans biofilms (MHIC >64 µg/ml), compared to planktonic counterparts, but retained activity against C. glabrata (MHIC=8 µg/ml) and C. krusei (MHIC= 4 µg/ml). AFG showed best activity against all Candida biofilms (MHIC 0.5-1 µg/ml). Conclusions: Microcalorimetry allows real-time evaluation of antifungal activity on planktonic and biofilm Candida spp. AFG showed better activity against planktonic and biofilms Candida

Abstract Number: M-974

Conference Year: 2012

Link to conference website: NULL

New link: NULL

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