scholarly journals Multicentre validation of a EUCAST method for the antifungal susceptibility testing of microconidia-forming dermatophytes

2020 ◽  
Vol 75 (7) ◽  
pp. 1807-1819 ◽  
Author(s):  
Maiken Cavling Arendrup ◽  
Karin Meinike Jørgensen ◽  
Jesus Guinea ◽  
Katrien Lagrou ◽  
Erja Chryssanthou ◽  
...  
Keyword(s):  
Target Gene ◽  
Susceptibility Testing ◽  
Trichophyton Rubrum ◽  
Antifungal Susceptibility ◽  
Error Rates ◽  
High Reproducibility ◽  
Upper Limits ◽  
Gene Mutant ◽  
Testing Error

Abstract Objectives Terbinafine resistance is increasingly reported in Trichophyton, rendering susceptibility testing particularly important in non-responding cases. We performed a multicentre evaluation of six EUCAST-based methods. Methods Ten laboratories susceptibility tested terbinafine, itraconazole, voriconazole and amorolfine against a blinded panel of 38 terbinafine WT and target gene mutant isolates. E.Def 9.3.1 modifications included: medium with/without addition of chloramphenicol and cycloheximide (CC), incubation at 25°C to 28°C for 5–7 days and three MIC endpoints [visually and spectrophotometrically (90%/50% inhibition)], generating 7829 MICs. Quality control (QC) strains were Aspergillus flavus ATCC 204304 and CNM-CM1813. Eyeball, ECOFFinder (where ECOFF stands for epidemiological cut-off) and derivatization WT upper limits (WT-ULs), very major errors (VMEs; mutants with MICs ≤WT-ULs) and major errors (MEs; WT isolates with MICs >WT-ULs) were determined. Results MICs fell within the QC ranges for ATCC 204304/CNM-CM1813 for 100%/96% (voriconazole) and 84%/84% (itraconazole), respectively. Terbinafine MICs fell within 0.25–1 mg/L for 96%/92%, suggesting high reproducibility. Across the six methods, the number of terbinafine MEs varied from 2 to 4 (2.6%–5.2%) for Trichophyton rubrum and from 0 to 2 (0%–2.0%) for Trichophyton interdigitale. Modes for WT and mutant populations were at least seven 2-fold dilutions apart in all cases. Excluding one I121M/V237I T. rubrum mutant and two mixed WT/mutant T. interdigitale specimens, the numbers of VMEs were as follows: T. rubrum: CC visual, 1/67 (1.5%); CC spectrophotometric 90% inhibition, 3/59 (5.1%); and CC spectrophotometric 50% inhibition, 1/67 (1.5%); and T. interdigitale: none. Voriconazole and amorolfine MICs were quite uniform, but trailing growth complicated determination of itraconazole visual and spectrophotometric 90% inhibition MIC. Conclusions Although none of the laboratories was experienced in dermatophyte testing, error rates were low. We recommend the CC spectrophotometric 50% inhibition method and provide QC ranges and WT-ULs for WT/non-WT classification.

scholarly journals EUCAST Determination of Olorofim (F901318) Susceptibility of Mold Species, Method Validation, and MICs

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Karin Meinike Jørgensen ◽  
Karen M. T. Astvad ◽  
Rasmus Krøger Hare ◽  
Maiken Cavling Arendrup
Keyword(s):  
Fusarium Solani ◽  
Susceptibility Testing ◽  
Wild Type ◽  
Preparation Methods ◽  
Content Type ◽  
Microtiter Plates ◽  
Upper Limits ◽  
Limited Variation

ABSTRACT Olorofim is a novel antifungal agent with in vitro activity against Aspergillus and some other molds. Here, we addressed technical aspects for EUCAST olorofim testing and generated contemporary MIC data. EUCAST E.Def 9.3.1 testing was performed comparing two plate preparation methods (serial dilution in medium [serial plates] versus predilution in DMSO [ISO plates]), two lots of olorofim, visual (visual-MIC) versus spectrophotometer (spec-MIC) reading, and four polystyrene plates using 34 to 53 Aspergillus isolates from five genera. Subsequently, olorofim MICs were compared to itraconazole, voriconazole, posaconazole, and amphotericin B MICs for 298 clinical mold isolates (2016 to 2017). Wild-type upper limits (WT-UL) were determined following EUCAST principles for epidemiologic cutoff value (ECOFF) setting. Olorofim median MICs comparing serial plates and ISO plates were identical (25/36 [69%]) or one dilution apart (11/36 [31%]). Interperson agreement for visual-MICs was 92% to 94%/100% for ≤1/≤2 dilutions, respectively. The visual-MIC values across tested microtiter plates and olorofim lots revealed only discrete differences (≤1 dilution lower for treated plates). No single spec-MIC criterion was applicable to all species. Olorofim MICs were low against 275 Aspergillus species isolates (modal MIC, 0.06 mg/liter; MIC range, < 0.004 to 0.25 mg/liter) and three dermatophytes (MICs 0.03 to 0.06 mg/liter). MICs against Fusarium were diverse, with full inhibition of F. proliferatum (MIC, 0.016), 50% growth inhibition of Fusarium solani at 1 to 2 mg/liter, and no inhibition of F. dimerum. Olorofim displayed potent in vitro activity against most mold isolates and was associated with limited variation in EUCAST susceptibility testing.

scholarly journals Regional Differences in Antifungal Susceptibility of the Prevalent Dermatophyte Trichophyton rubrum

2020 ◽  
Vol 186 (1) ◽  
pp. 53-70
Author(s):  
Y. Jiang ◽  
W. Luo ◽  
P. E. Verweij ◽  
Y. Song ◽  
B. Zhang ◽  
...  
Keyword(s):  
Trichophyton Rubrum ◽  
Antifungal Susceptibility ◽  
Sensu Stricto ◽  
Antifungal Drugs ◽  
Primary Therapy ◽  
In Vitro Susceptibility ◽  
Minimal Inhibitory Concentrations ◽  
Upper Limits ◽  
In Vitro Susceptibility Testing

AbstractIn vitro susceptibility testing for Trichophyton rubrum has shown resistance to terbinafine, azoles and amorolfine, locally, but epidemiological cutoffs are not available. In order to assess the appropriateness of current first-line antifungal treatment for T. rubrum in China, we characterized antifungal susceptibility patterns of Chinese T. rubrum strains to nine antifungals and also described the upper limits of wild-type (WT) minimal inhibitory concentrations (MIC) (UL-WT) based on our study and another six studies published during the last decades. Sixty-two clinical isolates originating from seven provinces in China were identified as T. rubrum sensu stricto; all Chinese strains showed low MICs to eight out of nine antifungal drugs. Terbinafine (TBF) showed the lowest MICs of all antifungal classes tested in both the Chinese and global groups, with a 97.5% UL-WT MIC-value of 0.03 mg/L. No non-WT isolates were observed for TBF in China, but were reported in 18.5% of the global group. Our study indicated that TBF was still the most active drug for Chinese T. rubrum isolates, and all strains were within the WT-population. TBF therefore remains recommended for primary therapy to dermatophytosis caused by T. rubrum in China now, but regular surveillance of dermatophytes and antifungal susceptibility is recommended.

Evaluation of Microscan WalkAway for determination of ceftazidime/avibactam and ceftolozane/tazobactam susceptibility in carbapenem-resistant Gram-negative bacilli

2021 ◽  
Author(s):  
Carmen Antonia Sanches Ito ◽  
Larissa Bail ◽  
Lavinia Nery Villa Stangler Arend ◽  
Kleber Oliveira Silva ◽  
Simone Sebold Michelotto ◽  
...  
Keyword(s):  
Error Rate ◽  
Reference Method ◽  
Multidrug Resistant ◽  
Error Rates ◽  
Gram Negative ◽  
Carbapenem Resistant ◽  
Testing Error ◽  
Microscan Walkaway ◽  
Clinically Significant

Background: We evaluated the performance of ceftazidime/avibactam and ceftolozane/tazobactam MicroScan Neg multidrug-resistant MIC 1 NMR1 panel for clinical carbapenem-nonsusceptible Gram-negative bacilli isolates. Methods: We evaluated 212 clinically significant carbapenem-nonsusceptible Gram-negative bacilli 139 Pseudomonas aeruginosa and 73 KPC-producing Enterobacterales from 71 Brazilian hospitals 2013-2020. Ceftazidime/avibactam and ceftolozane/tazobactam MICs from the panel were compared with broth microdilution BMD test as the reference method. Essential agreement EA and categorical agreement CA were assessed. For P. aeruginosa , antimicrobial susceptibility testing error rates were calculated using the error-rate bound method. Results: Discrepancies were initially observed with 11 isolates, 4 resolved after retesting, 2 in favor of the NMR1 and 2 in favor of the BMD method. The ceftazidime/avibactam EA overall and evaluable was 100% for P. aeruginosa and Enterobacterales. CA was 100% for Enterobacterales , and 98.6% for P. aeruginosa . The ceftolozane/tazobactam EA was 98.6% and 100% overall and evaluable, respectively, and CA was 96.4% for P. aeruginosa . For ceftazidime/avibactam, no VME was found, and the ME rate was 4.2% 2/48. For ceftolozane/tazobactam and P. aeruginosa , using the CLSI breakpoints, the minor error mE was 11.4% and no VME or ME was found. While using EUCAST breakpoints, VME was 11.4% with no ME. The mE becomes ME or VME in the absence of the intermediate category. All categorical errors were also within 1 log of MIC variation, and the adjusted error rate for CLSI/EUCAST was 0% 0/212. Conclusions: The NMR1 panel is an option to test ceftazidime–avibactam for KPC-producing Enterobacterales and carbapenem-nonsusceptible P. aeruginosa . When ceftolozane–tazobactam MIC 4 mg/L are obtained using this method, an alert could be created, and the results could be confirmed by alternative method.

scholarly journals Development and multicentre validation of an agar-based screening method for echinocandin susceptibility testing of Aspergillus species

2019 ◽  
Vol 74 (8) ◽  
pp. 2247-2254 ◽  
Author(s):  
Joseph Meletiadis ◽  
Maria Siopi ◽  
Lamprini Kanioura ◽  
Karin Meinike Jørgensen ◽  
David S Perlin ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Screening Method ◽  
Colony Growth ◽  
Tween 20 ◽  
Optimal Test ◽  
And Control ◽  
Drug Free ◽  
Minimal Effective Concentration

Abstract Background Reference antifungal susceptibility testing of echinocandins against Aspergillus spp. relies on the determination of the minimal effective concentration, which is difficult to perform, time-consuming and subjective. We developed and evaluated in a multicentre study an agar-based screening method for echinocandin susceptibility testing of Aspergillus spp. Methods Forty WT isolates [10 Aspergillus fumigatus species complex (SC), 10 Aspergillus flavus SC, 10 Aspergillus terreus SC and 10 Aspergillus niger SC] and 4 non-WT A. fumigatus isolates with or without known fks alterations were used. The optimal test conditions and stability over time were evaluated in preliminary studies monitoring colony growth. Twenty-microlitre aliquots of 1–2 McFarland inocula in 0.1% Tween 20 aqueous solution were added to each well and plates were incubated for 24/48 h at 35 ± 2°C. Subsequently, all isolates were tested blindly at three centres using four-well screening plates, containing anidulafungin, caspofungin, micafungin or no antifungal in each of the four wells, respectively. Results WT isolates produced fluffy colonies on drug-free agar wells only. The non-WT isolates produced fluffy colonies on echinocandin-containing and control agar wells. Using the echinocandin concentrations of 0.25 mg/L anidulafungin, 1 mg/L caspofungin and 0.125 mg/L micafungin, and the compact (non-fluffy) versus fluffy colony morphology endpoint, all centres successfully discriminated non-WT and WT strains even after 24 h. Among the three echinocandins, anidulafungin produced the clearest endpoints. Conclusions The four-well plate agar method is suitable for echinocandin susceptibility screening of Aspergillus spp. and can be used to detect echinocandin non-WT isolates.

Antifungal susceptibility testing of Trichophyton rubrum by E-test

2007 ◽  
Vol 299 (2) ◽  
pp. 107-109 ◽  
Author(s):  
Maria Elisabete da Silva Barros ◽  
Daniel de Assis Santos ◽  
Júnia Soares Hamdan
Keyword(s):  
Susceptibility Testing ◽  
Trichophyton Rubrum ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing

scholarly journals Comparison of MIC Test Strip and Sensititre YeastOne with the CLSI and EUCAST Broth Microdilution Reference Methods for In Vitro Antifungal Susceptibility Testing of Cryptococcus neoformans

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Fatima Zohra Delma ◽  
Abdullah M. S. Al-Hatmi ◽  
Jochem B. Buil ◽  
Hein van der Lee ◽  
Marlou Tehupeiory-Kooreman ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Test Strip ◽  
Error Rates ◽  
Broth Microdilution ◽  
Content Type ◽  
In Vitro Antifungal Susceptibility

ABSTRACT We compared MIC test strip (MTS) and Sensititre YeastOne (SYO) methods with EUCAST and CLSI methods for amphotericin B, 5-fluocytosine, fluconazole, voriconazole, and isavuconazole against 106 Cryptococcus neoformans isolates. The overall essential agreement between the EUCAST and CLSI methods was >72% and >94% at ±1 and ±2 dilutions, respectively. The essential agreements between SYO and EUCAST/CLSI for amphotericin B, 5-flucytosine, fluconazole, and voriconazole were >89/>93% and between MTS and EUCAST/CLSI were >57/>75%. Very major error rates were low for amphotericin B and fluconazole (<3%) and a bit higher for the other drugs (<8%).

scholarly journals Multicenter Comparison of the Etest and EUCAST Methods for Antifungal Susceptibility Testing of Candida Isolates to Micafungin

2016 ◽  
Vol 60 (8) ◽  
pp. 5088-5091 ◽  
Author(s):  
M.-E. Bougnoux ◽  
E. Dannaoui ◽  
I. Accoceberry ◽  
A. Angoulvant ◽  
E. Bailly ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Antifungal Susceptibility Testing ◽  
Medical Mycology ◽  
Single Center ◽  
Content Type ◽  
Valuable Alternative

ABSTRACTIn vitrosusceptibility of 933Candidaisolates, from 16 French hospitals, to micafungin was determined using the Etest in each center. All isolates were then sent to a single center for determination of MICs by the EUCAST reference method. Overall essential agreement between the two tests was 98.5% at ±2 log2dilutions and 90.2% at ±1 log2dilutions. Categorical agreement was 98.2%. The Etest is a valuable alternative to EUCAST for the routine determination of micafungin MICs in medical mycology laboratories.

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