Interlaboratory Variability of Caspofungin MICs for Candida spp. Using CLSI and EUCAST Methods: Should the Clinical Laboratory Be Testing This Agent?

Espinel-Ingroff, Ana; Arendrup, Maiken Cavling; Pfaller, Michael A.; Bonfietti, Lucas Xavier; Bustamante, Beatriz; Cantón, Emilia; Chryssanthou, Erja; Cuenca‐Estrella, Manuel; Dannaoui, Éric; Fothergill, A.; Fuller, Jeffrey; Gaustad, Peter; González, Gloria M.; Guarro, Josep; Lass‐Flörl, Cornelia; Lockhart, Shawn R.; Meis, Jacques F.; Moore, Caroline B.; Ostrosky-Zeichner, Luis; Peláez, Teresa; Pukinskas, S. R. B. S.; St-Germain, G.; Szeszs, Maria Walderez; Turnidge, John

doi:10.1128/aac.01519-13

Cited by 187 publications

(162 citation statements)

References 21 publications

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“…Significant interlaboratory variability is a concern for caspofungin susceptibility testing performed using the CLSI and EUCAST broth microdilution methodologies (1). Although this variability can be observed among different species, the differences are most pronounced with C. glabrata and C. krusei (1,2,12).…”

Section: Discussionmentioning

confidence: 96%

“…ignificant interlaboratory variability has been reported for caspofungin susceptibility testing, with some laboratories reporting MIC values elevated above the revised CLSI clinical breakpoints (1). The interlaboratory variability is not without consequences, as it may result in major errors for caspofungin use (i.e., falsely interpreting an isolate as resistant to this echinocandin).…”

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confidence: 99%

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Effects of Treated versus Untreated Polystyrene on Caspofungin In Vitro Activity against Candida Species

et al. 2016

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Significant interlaboratory variability is observed in testing the caspofungin susceptibility of Candida species by both the CLSI and EUCAST broth microdilution methodologies. We evaluated the influence of treated versus untreated polystyrene microtiter trays on caspofungin MICs using 209 isolates of four Candida species, including 16 C. albicans and 11 C. glabrata isolates with defined FKS mutations. Caspofungin MICs were also determined using the commercially available YeastOne and Etest assays and 102 isolates. All C. glabrata isolates had caspofungin MICs of >0.5 g/ml, the clinical breakpoint for caspofungin resistance in this species, measured using trays made of treated polystyrene, regardless of the FKS status. In contrast, susceptible isolates could readily be distinguished from resistant/non-wild-type isolates when caspofungin MICs were measured using untreated polystyrene trays and both the YeastOne and Etest assays. Similar results were also observed for C. krusei isolates, as all isolates had caspofungin MICs above the threshold for resistance measured using treated polystyrene trays. In contrast, C. albicans isolates could be correctly identified as susceptible or resistant when caspofungin MICs were measured with treated or untreated trays and with the YeastOne and Etest assays. MICs falsely elevated above the resistance breakpoint were also not observed for C. tropicalis isolates. These results demonstrated that the use of treated polystyrene may be one factor that leads to falsely elevated caspofungin in vitro susceptibility results and that this may also be a greater issue for some Candida species than for others. Significant interlaboratory variability has been reported for caspofungin susceptibility testing, with some laboratories reporting MIC values elevated above the revised CLSI clinical breakpoints (1). The interlaboratory variability is not without consequences, as it may result in major errors for caspofungin use (i.e., falsely interpreting an isolate as resistant to this echinocandin). In a retrospective review of our antifungal susceptibility database using data from 2008 to 2012, we found that 95.6% of C. glabrata and 74.3% of C. krusei isolates would be classified as resistant to caspofungin on the basis of the revised CLSI echinocandin clinical breakpoints (2). Other laboratories have reported similar results (3). As the factors that lead to interlaboratory variability are unknown, we sought to determine if the choice of plastic used in the microtiter trays, either treated or untreated polystyrene, could affect caspofungin MIC values. These trays are designed for cell cultures, and treatment of the plastic, either by coating or corona discharge to impart an electrical charge to the plastic, allows the cells to adhere. Our laboratory has historically used 96-well microtiter trays made of treated polystyrene, while other laboratories have used those made of untreated plastic. The CLSI M27-A3 standard for yeast antifungal susceptibility testing has not addressed plastic type or recomm...

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Section: Discussionmentioning

confidence: 96%

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confidence: 99%

Effects of Treated versus Untreated Polystyrene on Caspofungin In Vitro Activity against Candida Species

et al. 2016

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“…Breakpoints were specifically developed to identify C. glabrata harboring FKS mutations by considering multiple factors, such as ␤-1,3-D-glucan synthase enzyme kinetics and echinocandin pharmacokinetic and pharmacodynamic data (6,9). However, despite standardized methodologies, important limitations with the in vitro susceptibility testing cannot be ignored: first, the assay has a time-consuming setup and intrinsically slow turnaround time, requiring 24 to 48 h after isolate recovery; second, interlaboratory variability of caspofungin MICs has limited direct testing of this drug (10); and third, susceptible and resistant populations overlap (11).…”

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confidence: 99%

Rapid Detection of FKS -Associated Echinocandin Resistance in Candida glabrata

Zhao

Nagasaki

Kordalewska

et al. 2016

Antimicrob Agents Chemother

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A novel and highly accurate diagnostic assay platform was established for rapid identification of FKS mutations associated with echinocandin resistance in Candida glabrata. The assay platform uses allele-specific molecular beacon and DNA melt analysis following asymmetric PCR. A dual assay for FKS1 and FKS2 was developed to identify within 3 h the most common and clinically relevant resistance-associated mutations, including 8 FKS1 HS1 (wild type [WT], S629P, F625S, D632Y, D632E [T1896G], D632E [T1896A], I634V, and F625F) and 7 FKS2 HS1 (WT, F659del, F659S, F659V, F659L, S663P, and S663F) genotypes. A blinded panel of 188 C. glabrata clinical isolates was tested by both assays. The molecular diagnostic results from the dual assay were 100% concordant with data obtained from DNA sequencing. This platform has the potential to overcome the deficiencies of existing in vitro susceptibility-based assays to identify echinocandin-resistant C. glabrata and holds promise as a surrogate diagnostic method to better direct echinocandin therapy.C andida glabrata is the second leading cause of candidemia in the United States, as well as in northern and eastern areas of Europe (1-3). With rapidly expanded usage of echinocandins, the first-line therapy for invasive candidiasis, an alarming trend of rising echinocandin resistance in C. glabrata has posed a serious clinical challenge (4-6). Detection of echinocandin resistance can be assessed phenotypically, using either microdilution or disc diffusion MIC assays performed in accordance with guidance of the Clinical and Laboratory Standards Institute (CLSI) M27-A3 standard (7) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) Definitive Document Edef 7.2 (8). Current echinocandin clinical breakpoints for C. glabrata were established by the CLSI for all echinocandins and by EUCAST for micafungin and anidulafungin. Breakpoints were specifically developed to identify C. glabrata harboring FKS mutations by considering multiple factors, such as ␤-1,3-D-glucan synthase enzyme kinetics and echinocandin pharmacokinetic and pharmacodynamic data (6, 9). However, despite standardized methodologies, important limitations with the in vitro susceptibility testing cannot be ignored: first, the assay has a time-consuming setup and intrinsically slow turnaround time, requiring 24 to 48 h after isolate recovery; second, interlaboratory variability of caspofungin MICs has limited direct testing of this drug (10); and third, susceptible and resistant populations overlap (11).Clinical echinocandin resistance in C. glabrata is associated with amino acid substitutions caused by mutations in specific hotspot (HS) regions of FKS1 and FKS2, which encode the drug target ␤-1,3-D-glucan synthase. A recent study performed among patients with invasive candidiasis due to C. glabrata has shown that the FKS genotype is a better indicator of echinocandin therapeutic failure than MIC (12).To date, DNA sequencing is the only means to identify mutations within FKS1 and FKS2 genes. Sequence data a...

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“…According to Espinel-Ingrof et al (2013), use of the CLSI species-specific CAS breakpoint could lead to results indicating an excessive number of sensitive isolates (such as C. glabrata and C. krusei) as resistant. Therefore, they suggested that routine testing or reporting of CLSI CAS MICs for Candida, according to CLSI (2012), is not suitable (21). Generally, in this study, CAS was an effective agent against Candida species, except some C. glabrata and C. krusei species (MIC90 = 2 µg/mL).…”

Section: Discussionmentioning

confidence: 99%

Multicenter Identification and Antifungal Susceptibility Patterns of Candida Species Isolated from Clinical Samples

Badiee

Badali

Diba

et al. 2017

Jundishapur J Microbiol

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Background: Invasive fungal infections without proper treatment could lead to high mortality rate, especially in immunocompromised patients. Candida species distribution and drug susceptibility patterns vary in different areas. Understanding the etiologic agents and drug susceptibility patterns in each region are required for the best management of patients with Candida infections. Objectives: The aim of this study was to identify Candida species isolated from clinical samples of six university hospitals in Iran and detect their susceptibility patterns to seven antifungal agents. Methods: Clinical samples from patients with fungal infections were cultured on Sabouraud dextrose agar. Isolated yeasts were identified by API 20C AUX kit, according to the manufacturer's instructions. Drug susceptibility patterns to amphotericin B, caspofungin, voriconazole, fluconazole, posaconazole, itraconazole and ketoconazole were determined, according to CLSI M27-A3 and S4. Results: In total, 428 species of Candida were isolated from clinical samples (1950 samples). Most isolated species were Candida albicans, followed by C. tropicalis, C. parapsilosis, C. kefyr, C. famata, C. glabrata, C. krusei, C. dubliniensis, C. guilliermondii and C. lusitaniae. Sensitivity rate of C. albicans to amphotericin B, caspofungin, voriconazole, fluconazole, and itraconazole was 96.6%, 99.5%, 88.6%,

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Interlaboratory Variability of Caspofungin MICs for Candida spp. Using CLSI and EUCAST Methods: Should the Clinical Laboratory Be Testing This Agent?

Cited by 187 publications

References 21 publications

Effects of Treated versus Untreated Polystyrene on Caspofungin In Vitro Activity against Candida Species

Effects of Treated versus Untreated Polystyrene on Caspofungin In Vitro Activity against Candida Species

Rapid Detection of FKS -Associated Echinocandin Resistance in Candida glabrata

Multicenter Identification and Antifungal Susceptibility Patterns of Candida Species Isolated from Clinical Samples

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