Killing Rates for Caspofungin Against Candida albicans After Brief and Continuous Caspofungin Exposure in the Presence and Absence of Serum

Renátó Kovács, Rudolf Gesztelyi, David S. Perlin, Gábor Kardos, Marianna Domán, Réka Berényi, László Majoros

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

It was previously demonstrated that brief (≤1 h) exposures to echinocandins are as effective to kill Candida albicans cells as continuous 24-h exposure. However, killing rates after continuous and short (1 h) echinocandin exposures to C. albicans have not yet been evaluated in RPMI-1640 with and without 50 % serum. We evaluated four echinocandin susceptible C. albicans bloodstream isolates, ATCC 10231 type strain and an echinocandin-resistant isolate (DPL20, FKS F645P). Caspofungin MICs, time-kill and postantifungal effect (PAFE) tests were performed in RPMI-1640 with and without 50 % serum. Killing rates (k values) in time-kill and PAFE experiments were determined for each strain and concentration. In time-kill experiments, colony count decreases were isolate- and concentration-dependent at 0.25, 1, 4, 8, 16 and 32 mg/L in RPMI-1640, but concentration-independent at 1, 4, 8, 16 and 32 mg/L in 50 % serum. One-hour caspofungin exposure at 4, 16 and 32 mg/L resulted in CFU decreases comparable with the results obtained in time-kill experiments in RPMI-1640, but 50 % serum at 4, 16 and 32 mg/L allowed growth of all isolates (k values were negative) (P < 0.05–0.001). PAFE in 50 % serum decreased markedly at 4, 16 and 32 mg/L. Killing rates remained high and concentration-independent in 50 % serum in case of continuous but not in case of brief caspofungin exposure. As only a short growth inhibition without killing was observed in 50 % serum, clinical relevance of caspofungin PAFE in vivo is questionable.

Original languageEnglish
Pages (from-to)197-206
Number of pages10
JournalMycopathologia
Volume178
Issue number3-4
DOIs
Publication statusPublished - Jan 1 2014

Keywords

  • Echinocandins
  • Postantifungal effect
  • Serum-based susceptibility testing

ASJC Scopus subject areas

  • Microbiology
  • Applied Microbiology and Biotechnology
  • Agronomy and Crop Science
  • veterinary (miscalleneous)

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