Exploring the In Vitro Resistance of Candida parapsilosis to Echinocandins.
The naturally high minimum inhibitory concentration exhibited by echinocandins against Candida parapsilosis has been known since the first introduction of these antifungal agents. Despite this awareness, clinical failures have not been reported; consequently, the resistance of C. parapsilosis to echinocandins remains unexplored. We exposed 30 isolates of C. parapsilosis to echinocandins (caspofungin, micafungin, and anidulafungin) in vitro and studied the effects of this exposure. After 60 exposures, 80, 67, and 60 % of the isolates changed from susceptible to non-susceptible to caspofungin, micafungin, and anidulafungin, respectively. In addition, four strains exhibited cross-resistance to all three echinocandins. Based on the M27-A3 (CLSI, 2008) and M27-S4 (CLSI, 2012) techniques, the susceptibility of the resistant strains to other antifungal agents was assayed. All of the tested echinocandin-resistant strains were susceptible to amphotericin B, and the resistance rate to fluconazole, voriconazole, and flucytosine was 73.3, 43.3, and 20 %, respectively. The exposure of C. parapsilosis to the three echinocandins generated cross-resistant strains and an unexpected in vitro resistance to azoles and flucytosine.
Health Sciences Centre, Federal University of Santa Maria, Santa Maria, RS, Brazil. francielichassot@gmail.com.|Departamento de Microbiologia e Parasitologia, Universidade Federal de Santa Maria (UFSM), Av. Roraima n° 1000, Prédio 20, Sala 4139, Santa Maria, RS, CEP 97105-900, Brazil. francielichassot@gmail.com.
Francieli
F
Chassot
Health Sciences Centre, Federal University of Santa Maria, Santa Maria, RS, Brazil.
Tarcieli Pozzebon
TP
Venturini
Health Sciences Centre, Federal University of Santa Maria, Santa Maria, RS, Brazil.
Fernanda Baldissera
FB
Piasentin
Health Sciences Centre, Federal University of Santa Maria, Santa Maria, RS, Brazil.
Luana
L
Rossato
Department of Clinical Analysis and Biomedicine, State University of Maringa, Maringa, PR, Brazil.
Adriana
A
Fiorini
Department of Clinical Analysis and Biomedicine, State University of Maringa, Maringa, PR, Brazil.
Terezinha Inez Estivalet
TI
Svidzinski
Health Sciences Centre, Federal University of Santa Maria, Santa Maria, RS, Brazil.
Sydney Hartz
SH
Alves
D000935:Antifungal Agents / Q000494:pharmacology*; D001393:Azoles / Q000494:pharmacology; D002175:Candida / Q000187:drug effects*; D002177:Candidiasis / Q000382:microbiology; D025141:Drug Resistance, Fungal; D054714:Echinocandins / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests
D000935:Antifungal Agents; D001393:Azoles; D054714:Echinocandins
Antifungal drug resistance; Candida parapsilosis; Echinocandins; Susceptibility tests