The Etest Performed Directly on Blood Culture Bottles Is a Reliable Tool for Detection of Fluconazole-Resistant Candida albicans Isolates

Escribano, Pilar; Marcos-Zambrano, Laura Judith; Gómez, Ana; Fresno, Carlos del; Martínez-Jiménez, M. Carmen; Bouza, Emilio; Guinea, Jesús

doi:10.1128/aac.00400-17

Cited by 13 publications

(12 citation statements)

References 43 publications

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“…The following tests were performed on isavuconazole nonewildtype isolates to discriminate between trailing or nonsusceptibility: antifungal susceptibility to fluconazole, voriconazole and posaconazole (MilliporeSigma, St Louis, MO, USA); and isavuconazole MICs obtained either by EUCAST but after incubation of trays at 25 C [11] or by Etest (bioM erieux España, Madrid, Spain) performed as recommended by the manufacturer.…”

Section: Antifungal Susceptibility Testingmentioning

confidence: 99%

Isavuconazole is highly active in vitro against Candida species isolates but shows trailing effect

Marcos-Zambrano

Gómez

Sánchez‐Carrillo

et al. 2018

Clinical Microbiology and Infection

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Section: Antifungal Susceptibility Testingmentioning

confidence: 99%

Isavuconazole is highly active in vitro against Candida species isolates but shows trailing effect

Marcos-Zambrano

Gómez

Sánchez‐Carrillo

et al. 2018

Clinical Microbiology and Infection

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“…In the first study, the Etest was evaluated on blood cultures for the detection of fluconazole resistance in C. albicans. The results showed 100% CA with reference broth microdilution techniques (both CLSI and EUCAST) when trailing was ruled out [106]. In the second study, direct susceptibility by Etest was performed for micafungin and anidulafungin-susceptible and -resistant strains.…”

Section: Etest For Direct Antifungal Susceptibility Testing On Blood mentioning

confidence: 96%

“…The Etest method for direct MIC determination from positive blood culture bottles was evaluated and described below [104][105][106][107][108]. The first evaluation was conducted on 138 positive blood cultures containing yeasts (mainly Candida spp.).…”

Section: Etest For Direct Antifungal Susceptibility Testing On Blood mentioning

confidence: 99%

“…In a prospective study that compared Etest to the CLSI disk diffusion method, a CA of 100% for fluconazole, voriconazole, amphotericin B and 86.2% for caspofungin was reported between the two techniques [108]. Two other studies focused on the ability of direct Etest to detect resistance to fluconazole and echinocandins in blood cultures [104,106]. In the first study, the Etest was evaluated on blood cultures for the detection of fluconazole resistance in C. albicans.…”

Section: Etest For Direct Antifungal Susceptibility Testing On Blood mentioning

confidence: 99%

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Antifungal Susceptibly Testing by Concentration Gradient Strip Etest Method for Fungal Isolates: A Review

Dannaoui

Espinel-Ingroff

2019

JoF

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Antifungal susceptibility testing is an important tool for managing patients with invasive fungal infections, as well as for epidemiological surveillance of emerging resistance. For routine testing in clinical microbiology laboratories, ready-to-use commercial methods are more practical than homemade reference techniques. Among commercially available methods, the concentration gradient Etest strip technique is widely used. It combines an agar-based diffusion method with a dilution method that determinates a minimal inhibitory concentration (MIC) in µg/mL. Many studies have evaluated the agreement between the gradient strip method and the reference methods for both yeasts and filamentous fungi. This agreement has been variable depending on the antifungal, the species, and the incubation time. It has also been shown that the gradient strip method could be a valuable alternative for detection of emerging resistance (non-wild-type isolates) as Etest epidemiological cutoff values have been recently defined for several drug-species combinations. Furthermore, the Etest could be useful for direct antifungal susceptibility testing on blood samples and basic research studies (e.g., the evaluation of the in vitro activity of antifungal combinations). This review summarizes the available data on the performance and potential use of the gradient strip method.

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“…Molecular detection of resistance would speed up the results, although to date these techniques are pending on validation for their use with blood samples (5,13). In a previous study, we showed that the Etest directly performed on positive blood cultures (ET DIR ) is a reliable procedure to rapidly detect fluconazole-and echinocandin-resistant isolates (14)(15)(16). Moreover, anidulafungin-containing plates were useful to screen for the presence of echinocandin-resistant C. glabrata isolates directly from positive blood cultures (16).…”

mentioning

confidence: 99%

Detection of Echinocandin-Resistant Candida glabrata in Blood Cultures Spiked with Different Percentages of FKS2 Mutants

Bordallo-Cardona

Sánchez‐Carrillo

Bouza

et al. 2019

Antimicrob Agents Chemother

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Infections caused by the coexistence ofCandida glabrataechinocandin-resistant and echinocandin-susceptible cells may be possible, and the detection ofFKSmutants when the proportions ofFKSmutants are underrepresented poses a problem. We assessed the role of EUCAST and methods directly performed on positive blood cultures—Etest (ETDIR) and anidulafungin-containing agar plate assays—for detecting resistance inC. glabrataisolates containing different amounts of echinocandin-susceptible and -resistantCandida glabrataisolates. We studied 10 pairs ofC. glabrataisolates involving parental echinocandin-susceptible isolates and isogenic echinocandin-resistantFKSmutant isolates. Three inocula per pair (1 × 103to 5 × 103, 1 × 102to 5 × 102, and 10 to 50 CFU/ml) spanning suspensions with different amounts of susceptible/resistant isolates (9/1, 5/5, and 1/9 proportions for each the three inocula) were prepared. The suspensions were spiked in Bactec bottles and incubated until they were positive, and the three methods were compared. The EUCAST method showed echinocandin resistance when the bottles were spiked with susceptible/resistant isolates at 5/5 and 1/9 proportions; the results for the suspensions with a 9/1 proportion of susceptible/resistant isolates were susceptible for three pairs. We observed with the ETDIRresistance to both echinocandins in all pairs (resistance to micafungin and anidulafungin; MICs, ≥0.064 mg/liter and ≥0.125 mg/liter, respectively) and a double ring of growth inhibition in two pairs. The anidulafungin-containing plates showed fungal growth in the 90 spiked blood cultures at 48 h. Testing of echinocandin susceptibility with the ETDIRdirectly on the positive blood culture bottles is a reliable and rapid method to detect echinocandin resistance inC. glabrata. On the other hand, resistance can be missed with the EUCAST method when resistant isolates are underrepresented.

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The Etest Performed Directly on Blood Culture Bottles Is a Reliable Tool for Detection of Fluconazole-Resistant Candida albicans Isolates

Cited by 13 publications

References 43 publications

Isavuconazole is highly active in vitro against Candida species isolates but shows trailing effect

Isavuconazole is highly active in vitro against Candida species isolates but shows trailing effect

Antifungal Susceptibly Testing by Concentration Gradient Strip Etest Method for Fungal Isolates: A Review

Detection of Echinocandin-Resistant Candida glabrata in Blood Cultures Spiked with Different Percentages of FKS2 Mutants

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