Comparison of the Etest and the Sensititre Colorimetric Methods with the NCCLS Proposed Standard for Antifungal Susceptibility Testing of
            <i>Aspergillus</i>
            Species

Meletiadis, Joseph; Mouton, Johan W.; Meis, Jacques F.; Bouman, Bianca A.; Verweij, Paul E.

doi:10.1128/jcm.40.8.2876-2885.2002

Cited by 63 publications

(68 citation statements)

References 42 publications

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“…and Aspergillus spp. (14,15). It changes from blue to pink as a result of growth (16) and allows for the visual and spectrophotometric determination of MIC values.…”

Section: Discussionmentioning

confidence: 99%

Antifungal Susceptibility Testing of Malassezia spp. with an Optimized Colorimetric Broth Microdilution Method

et al. 2017

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Malassezia is a genus of lipid-dependent yeasts. It is associated with common skin diseases such as pityriasis versicolor and atopic dermatitis and can cause systemic infections in immunocompromised individuals. Owing to the slow growth and lipid requirements of these fastidious yeasts, convenient and reliable antifungal drug susceptibility testing assays for Malassezia spp. are not widely available. Therefore, we optimized a broth microdilution assay for the testing of Malassezia that is based on the CLSI and EUCAST assays for Candida and other yeasts. The addition of ingredients such as lipids and esculin provided a broth medium formulation that enabled the growth of all Malassezia spp. and could be read, with the colorimetric indicator resazurin, by visual and fluorescence readings. We tested the susceptibility of 52 strains of 13 Malassezia species to 11 commonly used antifungals. MIC values determined by visual readings were in good agreement with MIC values determined by fluorescence readings. The lowest MICs were found for the azoles itraconazole, posaconazole, and voriconazole, with MIC 90 values of 0.03 to 1.0 g/ml, 0.06 to 0.5 g/ml, and 0.03 to 2.0 g/ml, respectively. All Malassezia spp. were resistant to echinocandins and griseofulvin. Some Malassezia spp. also showed high MIC values for ketoconazole, which is the most widely recommended topical antifungal to treat Malassezia skin infections. In summary, our assay enables the fast and reliable susceptibility testing of Malassezia spp. with a large panel of different antifungals.

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“…and Aspergillus spp. (14,15). It changes from blue to pink as a result of growth (16) and allows for the visual and spectrophotometric determination of MIC values.…”

Section: Discussionmentioning

confidence: 99%

Antifungal Susceptibility Testing of Malassezia spp. with an Optimized Colorimetric Broth Microdilution Method

et al. 2017

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“…In contrast, Meletiadis et al (11) found that itraconazole MICs generated by Sensititre YeastOne were lower than those generated by the NCCLS method.…”

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confidence: 90%

“…For itraconazole, Meletiadis et al (11) found that the level of agreement between the methods was greater after 48 h of incubation (84.6%) than that after 24 h of incubation (44.6%). Martín-Mazuelos et al (10) also found the best agreement after 48 h of incubation for this antifungal agent (90.2%).…”

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confidence: 99%

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Comparison of the Sensititre YeastOne Colorimetric Antifungal Panel with a Modified NCCLS M38-A Method To Determine the Activity of Voriconazole against Clinical Isolates of Aspergillus spp

et al. 2004

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The susceptibilities of 63 isolates of Aspergillus spp. to voriconazole were evaluated by a modified NCCLS M38-A method and the Sensititre YeastOne method. The overall agreement was 82.5%, ranging from 100% for Aspergillus niger and Aspergillus terreus to 62.5% for Aspergillus flavus. Discrepancies between the methods were due to higher Sensititre MICs. The Sensititre YeastOne method could have potential value for susceptibility testing of Aspergillus spp. to voriconazole.Over the past decades, the incidence of invasive fungal infections has increased, especially those caused by Aspergillus species (18). The treatment of choice for infected patients remains amphotericin B, although alternative drugs with activities against Aspergillus species are becoming available for clinical use, including antifungal azoles and echinocandins (6,18). Because the number of serious infections caused by Aspergillus spp. has increased, as has the resistance of Aspergillus spp. to established agents, determination of the in vitro susceptibilities of Aspergillus isolates to both established and investigational agents is necessary (6).There is a great need for an easier and reproducible method for in vitro susceptibility testing of filamentous fungi as a guide to selecting and monitoring antifungal therapy. Alternatives to the NCCLS method are currently under investigation, including two commercial methods, E-test and Sensititre YeastOne, which have been evaluated for yeast and molds (1,3,5,6,9,10,11,(13)(14)(15)(16)(17).Our study represents an evaluation of the suitability of Sensititre YeastOne for determining the susceptibilities of Aspergillus spp. isolates to voriconazole. This test is a commercial colorimetric panel that consists of a disposable tray which contains dried serial dilutions of five antifungal agents in individual wells. The wells also contain an oxidation-reduction indicator (Alamar Blue) to generate clear-cut endpoints based on a visually detectable color change. MICs obtained by this method were compared to those obtained by the modified reference broth microdilution method (14).A total of 63 clinical Aspergillus isolates, comprising 24 Aspergillus fumigatus isolates, 16 Aspergillus flavus isolates, 9 Aspergillus terreus isolates, 8 Aspergillus niger isolates, 4 Aspergillus glaucus isolates, and 2 Aspergillus nidulans isolates, were included in this study. These isolates were recovered from clinical specimens of patients at the Valme University Hospital, Seville, Spain, and the Division of Infectious Diseases, Medical College of Virginia, Virginia Commonwealth University, Richmond.Culture, identification, and preservation of strains were done by using routine mycological methods (4, 7). Candida krusei ATCC 6258 and Candida parapsilosis ATCC 22019 were used as quality control strains for susceptibility testing procedures, and Aspergillus fumigatus ATCC 204305 and Aspergillus flavus ATCC 204304 were used as reference strains.The broth microdilution method was performed according to modified NCCLS standard M38-A gu...

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“…However, the latter methodology is based on visual MIC reading and requires long incubation periods ranging from 24 h for fast-growing fungi, including Rhizopus species, and up to 72 h for slow-growing fungi, such as Scedosporium species, before results are obtained. More objective methods (32) have been developed based on spectrophotometric readings (6,24), colorimetric assays (20,23,25), glucose consumption (13), glucan synthase inhibition (17), or quantification of fungal products (37), but with these methods, the time required to generate the results was not reduced. Although rapid susceptibility testing methods have been developed based on radiometric (26) and flow cytometric (1) assays generating results within 3 h, their use in routine clinical laboratories may be restricted due to the expensive equipment required (flow cytometer) or to the use of potentially hazardous substances.…”

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confidence: 99%

Use of Turbidimetric Growth Curves for Early Determination of Antifungal Drug Resistance of Filamentous Fungi

2003

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A previously described microbroth kinetic system (J. Meletiadis, J. F. Meis, J. W. Mouton, and P. E. Verweij, J. Clin. Microbiol. 39:478-484, 2001) based on continuous monitoring of changes in the optical density of fungal growth was used to describe turbidimetric growth curves of different filamentous fungi in the presence of increasing concentrations of antifungal drugs. Therefore, 24 clinical mold isolates, including Rhizopus oryzae, Aspergillus fumigatus, Aspergillus flavus, and Scedosporium prolificans, were tested against itraconazole, terbinafine, and amphotericin B according to NCCLS guidelines. Among various parameters of the growth curves, the duration of the lag phase was strongly affected by the presence of antifungal drugs. Exposure to increasing drug concentrations resulted in prolonged lag phases of the turbidimetric growth curves. The lag phases of the growth curves at drug concentrations which resulted in more than 50% growth (for itraconazole and terbinafine) and more than 75% growth (for amphotericin B) after 24 h of incubation for R. oryzae, 48 h for Aspergillus spp., and 72 h for S. prolificans were 4 h longer than the lag phases of the growth curves at the corresponding drug-free growth controls which varied from 4.4 h for R. oryzae, 6.5 h for A. flavus, 7.9 h for A. fumigatus, and 11.6 h for S. prolificans. The duration of the lag phases showed small experimental and interstrain variability, with differences of less than 2 h in most of the cases. Using this system, itraconazole and terbinafine resistance (presence of >50% growth) as well as amphotericin B resistance (presence of >75% growth) was determined within incubation periods of 5.0 to 7.7 h for R. oryzae (for amphotericin B resistance incubation for up to 12 h was required), 8.8 to 11.4 h for A. fumigatus, 6.7 to 8.5 h for A. flavus, and 13 to 15.6 h for S. prolificans while awaiting formal MIC determination by the NCCLS reference method.

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Comparison of the Etest and the Sensititre Colorimetric Methods with the NCCLS Proposed Standard for Antifungal Susceptibility Testing of Aspergillus Species

Cited by 63 publications

References 42 publications

Antifungal Susceptibility Testing of Malassezia spp. with an Optimized Colorimetric Broth Microdilution Method

Antifungal Susceptibility Testing of Malassezia spp. with an Optimized Colorimetric Broth Microdilution Method

Comparison of the Sensititre YeastOne Colorimetric Antifungal Panel with a Modified NCCLS M38-A Method To Determine the Activity of Voriconazole against Clinical Isolates of Aspergillus spp

Use of Turbidimetric Growth Curves for Early Determination of Antifungal Drug Resistance of Filamentous Fungi

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