Abstract
We determined micafungin, caspofungin and amphotericin B (AMB) minimum inhibitory concentration (MICs) and killing rates in RPMI-1640 and in RPMI-1640 with 50% serum against three Candida krusei bloodstream isolates. MIC ranges in RPMI-1640 were 0.125–0.25, 0.25 and 0.125–0.5 mg/L, in RPMI-1640 with 50% serum, MICs were 64–128-, 8- and 4–16-fold higher, respectively. In RPMI-1640 micafungin and caspofungin at 1, 4, 16 and 32 mg/L as well as AMB at 2 mg/L were fungicidal against all isolates in ≤3.96, ≤4.42 and 14.96 h, respectively. In RPMI-1640 with 50% serum, caspofungin was fungicidal for all isolates only at 32 mg/L, micafungin and AMB were fungistatic. In neutropenic mice, 5 mg/kg caspofungin and 1 mg/kg AMB were ineffective against two of the three isolates. Thus, in vivo efficacy of echinocandins and AMB is weak or absent against C. krusei. Prescribers treating C. krusei infections with echinocandins should watch out for clinical resistance and therapeutic failure.
Acknowledgment
The authors thank Katalin Orosz-Tóth for the expert technical assistance.
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No potential conflict of interests was reported by the author(s).
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Notes on contributors
Tamás Kardos
Tamas Kardos, Renato Kovacs, István Varga and Laszlo Majoros participated in concept and design of the study. Acquisition of data was done by Tamas Kardos, Aliz Bozó, Zoltán Tóth, Fruzsina Nagy. Analysis of data was also done by Renato Kovacs, Gabor Kardos and Laszlo Majoros. Tamas Kardos, Laszlo Majoros and Gabor Kardos contributed to article drafting. All of the authors approved the manuscript.
Istvan Varga
Tamas Kardos, Renato Kovacs, István Varga and Laszlo Majoros participated in concept and design of the study. Acquisition of data was done by Tamas Kardos, Aliz Bozó, Zoltán Tóth, Fruzsina Nagy. Analysis of data was also done by Renato Kovacs, Gabor Kardos and Laszlo Majoros. Tamas Kardos, Laszlo Majoros and Gabor Kardos contributed to article drafting. All of the authors approved the manuscript.
László Majoros
Tamas Kardos, Renato Kovacs, István Varga and Laszlo Majoros participated in concept and design of the study. Acquisition of data was done by Tamas Kardos, Aliz Bozó, Zoltán Tóth, Fruzsina Nagy. Analysis of data was also done by Renato Kovacs, Gabor Kardos and Laszlo Majoros. Tamas Kardos, Laszlo Majoros and Gabor Kardos contributed to article drafting. All of the authors approved the manuscript.