Rapid Detection of Echinocandins Resistance by MALDI-TOF MS in Candida parapsilosis Complex

Abstract

Mass spectrometry by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) was used to identify and differentiate the pattern of susceptibility of clinical isolates of Candida parapsilosis complex. 17 C. parapsilosis sensu stricto, 2 C. orthopsilosis, and 1 C. metapsilosis strains were obtained from blood cultures, and three different inocula (103, 105, and 107 CFU/mL) were evaluated against three echinocandins at concentrations ranging from 0.03 to 16 µg/mL after incubation of 1 h, 2 h, and 3 h. Drug-free control was used. The spectra obtained at these concentrations were applied to generate composite correlation index (CCI) matrices for each yeast individually. After cross correlations and autocorrelations of each spectra with null (zero) and maximal (16) concentrations, the CCI was used as separation parameter among spectra. Incubation time and inoculum were critical factors to reach higher precision and reliability of this trial. With an incubation time of 3 h and inoculum of 107 CFU/mL, it was possible to determine the breakpoint of the clinical yeasts by MALDI-TOF that presented high agreement with the clinical laboratory standard institute (CLSI) reference method. Herein, we show that mass spectrometry using the MALDI-TOF technique is powerful when it exploits antifungal susceptibility testing assays.

Are We Ready for Nosocomial Candida auris Infections? Rapid Identification and Antifungal Resistance Detection Using MALDI-TOF Mass Spectrometry May Be the Answer

“…Our study adds support to the successfully applied CCI-based proteomic approaches for antifungal resistance detection in Candida species, which offer the advantage to considerably reduce the time to result (three hours in our study) compared with conventional AFST methods ( Delavy et al, 2019 ; Roberto et al, 2020 ). In addition to being a cost-effective method (few euro-cents per run), our MS-AFST assay differs from the growth-based MALDI Biotyper antibiotic (antifungal) susceptibility test rapid assay (MBT-ASTRA) recently developed for rapid detection of AFG-resistant C. glabrata and C. auris isolates ( Vatanshenassan et al, 2018 ; Vatanshenassan et al, 2019 ).…”

“…with conventional AFST methods (Delavy et al, 2019;Roberto et al, 2020). In addition to being a cost-effective method (few euro-cents per run), our MS-AFST assay differs from the growthbased MALDI Biotyper antibiotic (antifungal) susceptibility test rapid assay (MBT-ASTRA) recently developed for rapid detection of AFG-resistant C. glabrata and C. auris isolates (Vatanshenassan et al, 2018;Vatanshenassan et al, 2019).…”

MALDI-TOF MS in a Medical Mycology Laboratory: On Stage and Backstage

“…Then, simplifications were made leading to the analysis of a matrix of 3 concentrations and a reduction of duration of the experiment to 3 h [63,64]. Triazoles were tested with C. albicans, C. tropicalis and C. glabrata [65,66] and echinocandins with the C. parapsilosis complex [67]. For C. glabrata and anidulafungin 85% of agreement was obtained in 3 h and increased to 97% in 12 h, suggesting that incubation time is critical [68].…”

Can We Improve Antifungal Susceptibility Testing?

“…Another study showed high accuracy of MALDI-TOF using clinical isolates of C. tropicalis and fluconazole in 4h, suggesting its possible application in clinical laboratories for rapid detection of resistant strains (Paul et al, 2018). Susceptibility to echinocandins of C. parapsilosis complex was also assessed after 4h and excellent agreements with reference techniques were found: 95% for anidulafungin and caspofungin, and 100% for micafungin (Roberto et al, 2020). For C. glabrata and anidulafungin, agreement was 85% after 3h and increased to 97% after 12h, suggesting that incubation time is critical (Vella et al, 2017).…”