scholarly journals Differential Fungicidal Activities of Amphotericin B and Voriconazole against Aspergillus Species Determined by Microbroth Methodology

2007 ◽  
Vol 51 (9) ◽  
pp. 3329-3337 ◽  
Author(s):  
Joseph Meletiadis ◽  
Charalampos Antachopoulos ◽  
Theodouli Stergiopoulou ◽  
Spyros Pournaras ◽  
Emmanuel Roilides ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Fungicidal Activity ◽  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Colorimetric Assay ◽  
Antifungal Susceptibility ◽  
Colorimetric Method ◽  
Reference Method ◽  
Fungicidal Action ◽  
Testing Reference

ABSTRACT Antifungal agents may differ in their fungicidal activities against Aspergillus spp. In order to compare the fungicidal activities of voriconazole and amphotericin B against 40 isolates of Aspergillus fumigatus, A. flavus, and A. terreus, we developed a new microbroth colorimetric method for assessing fungicidal activities and determining minimal fungicidal concentrations (MFCs). This methodology follows the antifungal susceptibility testing reference method M-38A for MIC determination. After drug removal and addition of fresh medium, growth of viable conidia adhering to the bottoms of the microtitration wells was assessed by a colorimetric assay of metabolic activity after 24 h of incubation. The new method was faster (six times), reproducible (92 to 97%), and in agreement with culture-based MFCs (91 to 100%). Differential fungicidal activities of voriconazole and amphotericin B were found among the three Aspergillus species, with A. fumigatus and A. flavus having the lowest (1 and 2 mg/liter, respectively) and A. terreus the highest (>16 mg/liter) median amphotericin B MFCs; A. flavus had a lower median voriconazole MFC (4 mg/liter) than the other species (>8 mg/liter; P < 0.05). Amphotericin B was fungicidal (MFC/MIC ≤ 4) against all A. fumigatus and A. flavus isolates but no A. terreus isolates, whereas voriconazole was fungicidal against 82% of A. flavus isolates and fungistatic (MFC/MIC > 4) against 94% of A. fumigatus and 84% of A. terreus isolates. The new methodology revealed a concentration-dependent sigmoid pattern of fungicidal effects, indicating that fungicidal activity is not an all-or-nothing phenomenon and that some degree of fungicidal action can be found even for agents considered fungistatic based on the MFC/MIC ratio.

scholarly journals Comparison of the Sensititre YeastOne and CLSI M38-A2 Microdilution Methods in Determining the Activity of Amphotericin B, Itraconazole, Voriconazole, and Posaconazole against Aspergillus Species

2018 ◽  
Vol 56 (10) ◽  
Author(s):  
Hsuan-Chen Wang ◽  
Ming-I Hsieh ◽  
Pui-Ching Choi ◽  
Chi-Jung Wu
Keyword(s):  
Aspergillus Fumigatus ◽  
Amphotericin B ◽  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Geometric Mean ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Aspergillus Species ◽  
Broth Microdilution ◽  
Content Type

ABSTRACT This study compared the YeastOne and reference CLSI M38-A2 broth microdilution methods for antifungal susceptibility testing of Aspergillus species. The MICs of antifungal agents were determined for 100 Aspergillus isolates, including 54 Aspergillus fumigatus (24 TR34/L98H isolates), 23 A. flavus, 13 A. terreus, and 10 A. niger isolates. The overall agreement (within 2 2-fold dilutions) between the two methods was 100%, 95%, 92%, and 90% for voriconazole, posaconazole, itraconazole, and amphotericin B, respectively. The voriconazole geometric mean (GM) MICs were nearly identical for all isolates using both methods, whereas the itraconazole and posaconazole GM MICs obtained using the YeastOne method were approximately 1 dilution lower than those obtained using the reference method. In contrast, the amphotericin B GM MIC obtained using the YeastOne method was 3.3-fold higher than that observed using the reference method. For the 24 A. fumigatus TR34/L98H isolates assayed, the categorical agreement (classified according to the CLSI epidemiological cutoff values) was 100%, 87.5%, and 83.3% for itraconazole, voriconazole, and posaconazole, respectively. For four A. niger isolates, the itraconazole MICs were >8 μg/ml using the M38-A2 method due to trailing growth, whereas the corresponding itraconazole MICs obtained using the YeastOne method were all ≤0.25 μg/ml without trailing growth. These data suggest that the YeastOne method can be used as an alternative for azole susceptibility testing of Aspergillus species and for detecting the A. fumigatus TR34/L98H isolates but that this method fails to detect A. niger isolates exhibiting trailing growth with itraconazole. Additionally, for isolates with azole MICs that approach or that are at susceptibility breakpoints or with high amphotericin B MICs detected using the YeastOne method, further MIC confirmation using the reference CLSI method is needed.

scholarly journals Comparison of Two Commercial Colorimetric Broth Microdilution Tests for Candida Susceptibility Testing: Sensititre YeastOne versus MICRONAUT-AM

2021 ◽  
Vol 7 (5) ◽  
pp. 356
Author(s):  
Sophie Philips ◽  
Frederik Van Van Hoecke ◽  
Emmanuel De De Laere ◽  
Steven Vervaeke ◽  
Roos De De Smedt ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Daily Practice ◽  
Broth Microdilution ◽  
Minimal Inhibitory Concentrations ◽  
Clinical Breakpoints ◽  
Susceptibility Tests

Two colorimetric broth microdilution antifungal susceptibility tests were compared, Sensititre YeastOne and MICRONAUT-AM for nine antifungal agents. One hundred clinical Candida isolates were tested, representing a realistic population for susceptibility testing in daily practice. The reproducibility characteristics were comparable. Only for fluconazole, caspofungin, 5-flucytosine and amphotericin B, an essential agreement of ≥90% could be demonstrated. Sensititre minimal inhibitory concentrations (MICs) were systematically higher than MICRONAUT MICs for all antifungals, except for itraconazole. CLSI clinical breakpoints (CBPs) and epidemiological cut-off values (ECVs) were used for Sensititre MICs while for MICRONAUT the EUCAST CBPs and ECVs were used. Only fluconazole, micafungin, and amphotericin B had a categorical agreement of ≥90%. For fluconazole, micafungin, and amphotericin B the susceptibility proportions were comparable. Susceptibility proportion of posaconazole and voriconazole was higher using the MICRONAUT system. For itraconazole and anidulafungin, the susceptibility proportion was higher using Sensititre. It was not possible to determine the true MIC values or the correctness of a S/I/R result since both commercial systems were validated against a different reference method. These findings show that there is a significant variability in susceptibility pattern and consequently on use of antifungals in daily practice, depending on the choice of commercial system.

scholarly journals Clinical Evaluation of the ASTY Colorimetric Microdilution Panel for Antifungal Susceptibility Testing

1998 ◽  
Vol 36 (9) ◽  
pp. 2609-2612 ◽  
Author(s):  
M. A. Pfaller ◽  
S. Arikan ◽  
M. Lozano-Chiu ◽  
Y.-S. Chen ◽  
S. Coffman ◽  
...  
Keyword(s):  
Growth Inhibition ◽  
Amphotericin B ◽  
Excellent Agreement ◽  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
National Committee ◽  
Microdilution Method

A method using a commercially prepared colorimetric microdilution panel (ASTY; Kyokuto Pharmaceutical Industrial Co., Ltd.) was compared in four different laboratories with the National Committee for Clinical Laboratory Standards (NCCLS) reference microdilution method by testing 802 clinical isolates of Candida spp. (C. albicans, C. glabrata, C. tropicalis,C. parapsilosis, C. krusei, C. lusitaniae, C. guilliermondii, C. lipolytica, C. rugosa, and C. zeylanoides) against amphotericin B, 5-fluorocytosine (5FC), fluconazole, and itraconazole. Reference MIC endpoints were established after 48 h of incubation, and ASTY endpoints were established after 24 and 48 h of incubation. ASTY endpoints were determined to be the time at which the color of the first well changed from red (indicating growth) to purple (indicating growth inhibition) or blue (indicating no growth). Excellent agreement (within 2 dilutions) between the reference and colorimetric MICs was observed. Overall agreement was 93% at 24 h and 96% at 48 h. Agreement ranged from 90% with itraconazole and 5FC to 96% with amphotericin B at 24 h and from 92% with itraconazole to 99% with amphotericin B and 5FC at 48 h. The ASTY colorimetric microdilution panel method appears to be comparable to the NCCLS reference method for testing the susceptibilities of Candida spp. to a variety of antifungal agents.

Use of spectrophotometric reading for in vitro antifungal susceptibility testing ofAspergillusspp.

1999 ◽  
Vol 45 (10) ◽  
pp. 871-874 ◽  
Author(s):  
Eric Dannaoui ◽  
Florence Persat ◽  
Marie-France Monier ◽  
Elisabeth Borel ◽  
Marie-Antoinette Piens ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Antifungal Susceptibility Testing ◽  
Aspergillus Species ◽  
National Committee ◽  
Broth Microdilution Method

A comparative study of visual and spectrophotometric MIC endpoint determinations for antifungal susceptibility testing of Aspergillus species was performed. A broth microdilution method adapted from the National Committee for Clinical Laboratory Standards (NCCLS) was used for susceptibility testing of 180 clinical isolates of Aspergillus species against amphotericin B and itraconazole. MICs were determined visually and spectrophotometrically at 490 nm after 24, 48, and 72h of incubation, and MIC pairs were compared. The agreement between the two methods was 99% for amphotericin B and ranged from 95 to 98% for itraconazole. It is concluded that spectrophotometric MIC endpoint determination is a valuable alternative to the visual reference method for susceptibility testing of Aspergillus species.Key words: antifungal, susceptibility testing, Aspergillus, spectrophotometric reading.

scholarly journals In VitroAntifungal Susceptibility of Clinically Relevant Species Belonging to Aspergillus SectionFlavi

2013 ◽  
Vol 57 (4) ◽  
pp. 1944-1947 ◽  
Author(s):  
Sarah S. Gonçalves ◽  
Alberto M. Stchigel ◽  
Josep Cano ◽  
Josep Guarro ◽  
Arnaldo L. Colombo
Keyword(s):  
Amphotericin B ◽  
Antifungal Agents ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Content Type

ABSTRACTThein vitroantifungal susceptibility of 77 isolates belonging to different clinically relevant species ofAspergillussectionFlavi, including those of different phylogenetic clades ofA. flavus, was tested for nine antifungal agents using a microdilution reference method (CLSI, M38-A2). Terbinafine and the echinocandins demonstrated lower MICs/MECs for all species evaluated, followed by posaconazole. Amphotericin B showed MICs ≥ 2 μg/ml for 38 (49.4%) of the 77 isolates tested.

scholarly journals Triazole susceptibility of Aspergillus species: environmental survey in Lagos, Nigeria and review of the rest of Africa

2021 ◽  
Vol 8 ◽  
pp. 204993612110443
Author(s):  
Cynthia Abosede Campbell ◽  
Iriagbonse Iyabo Osaigbovo ◽  
Rita Okeoghene Oladele
Keyword(s):  
Aspergillus Terreus ◽  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Reference Method ◽  
Aspergillus Species ◽  
Environmental Isolates ◽  
The Subject ◽  
Microbroth Dilution ◽  
Testing Reference ◽  
Isolated Species

Background: Triazole resistance is an emerging problem in the management of human aspergillosis globally and can arise in Aspergillus species which have been exposed to azole fungicides in the environment. We surveyed local government and council development areas in Lagos, Nigeria, to determine the distribution of Aspergillus species in the environment and their susceptibility to locally available triazole antifungal agents. We also reviewed the literature on the subject from the rest of Africa. Methods: A total of 168 soil samples from six locations in Lagos, Nigeria were processed and cultured on Saboraud dextrose agar impregnated with chloramphenicol to isolate Aspergillus species. Isolates were tested for susceptibility to itraconazole and voriconazole by microbroth dilution according to the European Committee on Antimicrobial Susceptibility Testing reference method. Relevant databases were searched to identify published work pertaining to triazole susceptibility of Aspergillus species in Africa. Results: A total of 117 Aspergillus species were isolated. Aspergillus niger was the most frequently isolated species (42.7%). Other species isolated were Aspergillus flavus, 37 (31.6%), Aspergillus terreus, 20 (17.1%), Aspergillus fumigatus, 5 (4.3%) and Aspergillus nidulans, 5 (4.3%). All isolates were susceptible to itraconazole and voriconazole. The literature review showed documented evidence of triazole-resistant Aspergillus species from East and West Africa. Conclusions: We found no triazole resistance in environmental isolates of Aspergillus in Lagos, Nigeria. Nevertheless, regular surveillance in clinical and environmental isolates is necessary in the light of findings from other African studies.

scholarly journals Comparison between E-test and CLSI broth microdilution method for antifungal susceptibility testing of Candida albicans oral isolates

2008 ◽  
Vol 50 (1) ◽  
pp. 7-10 ◽  
Author(s):  
Cristiane Yumi Koga-Ito ◽  
Juliana Pereira Lyon ◽  
Maria Aparecida de Resende
Keyword(s):  
Candida Albicans ◽  
Amphotericin B ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Test System ◽  
Test Method ◽  
In Vitro Susceptibility ◽  
Oral Candidosis ◽  
Broth Microdilution Method

Thirty Candida albicans isolated from oral candidosis patients and 30 C. albicans isolated from control individuals were studied. In vitro susceptibility tests were performed for amphotericin B, fluconazole, 5-flucytosine and itraconazole through the Clinical and Laboratorial Standards Institute (CLSI) reference method and E test system. The results obtained were analyzed and compared. MIC values were similar for the strains isolated from oral candidosis patients and control individuals. The agreement rate for the two methods was 66.67% for amphotericin B, 53.33% for fluconazole, 65% for flucytosine and 45% for itraconazole. According to our data, E test method could be an alternative to trial routine susceptibility testing due to its simplicity. However, it can not be considered a substitute for the CLSI reference method.

scholarly journals Flow Cytometry Antifungal Susceptibility Testing of Aspergillus fumigatus and Comparison of Mode of Action of Voriconazole vis-à-vis Amphotericin B and Itraconazole

2003 ◽  
Vol 47 (11) ◽  
pp. 3627-3629 ◽  
Author(s):  
Rama Ramani ◽  
Madhurama Gangwar ◽  
Vishnu Chaturvedi
Keyword(s):  
Flow Cytometry ◽  
Aspergillus Fumigatus ◽  
Amphotericin B ◽  
Cell Sorting ◽  
Mode Of Action ◽  
Fungicidal Activity ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing ◽  
Fluorescence Activated Cell Sorting

ABSTRACT Aspergillus fumigatus isolates were tested with three antifungals by flow cytometry (FC) and fluorescence-activated cell sorting. FC results after 4 h correlated well with MICs obtained by the NCCLS M38-A method; voriconazole exhibited fungicidal activity, albeit to a lesser extent than amphotericin B, but to a greater extent than itraconazole.

scholarly journals A multicentre study to optimize echinocandin susceptibility testing of Aspergillus species with the EUCAST methodology and a broth microdilution colorimetric method

2020 ◽  
Vol 75 (7) ◽  
pp. 1799-1806
Author(s):  
Joseph Meletiadis ◽  
Maria Siopi ◽  
Lamprini Kanioura ◽  
Karin Meinike Jørgensen ◽  
David S Perlin ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Colorimetric Assay ◽  
Antifungal Susceptibility ◽  
Colorimetric Method ◽  
Aspergillus Species ◽  
Subjective Time ◽  
Optimal Conditions ◽  
Drug Free ◽  
Minimal Effective Concentration

Abstract Background The determination of the minimal effective concentration (MEC) of echinocandins against Aspergillus species is subjective, time consuming and has been associated with very major errors. Methods The MECs/MICs of 40 WT [10 each of Aspergillus fumigatus species complex (SC), Aspergillus flavus SC, Aspergillus terreus SC and Aspergillus niger SC] and 4 non-WT A. fumigatus isolates were determined with EUCAST E.Def 9.3.1 read microscopically, macroscopically, spectrophotometrically and colorimetrically in three centres. The optimal conditions for spectrophotometric (single- versus multi-point readings) and colorimetric (XTT/menadione concentration and stability, incubation time) methods were evaluated in preliminary studies using different cut-offs for the determination of macroscopic, spectrophotometric and colorimetric MIC endpoints compared with the microscopically determined MEC. Inter-centre and inter-method essential (within one 2-fold dilution) agreement (EA) and categorical agreement (CA) were determined. Results Both macroscopic and spectrophotometric endpoint readings showed poor inter-centre EA (53%–66%) and low CA (41%–88%) in distinguishing WT from non-WT A. fumigatus SC isolates, while significant differences compared with the microscopic MECs were observed for all echinocandins (EA 6%–54%). For the colorimetric method, the optimal conditions were 400 mg/L XTT/6.25 μΜ menadione, incubation for 1–2 h until the drug-free control reached an absorbance at 450/630 nm of &gt;0.8 and use of 50% inhibition of XTT conversion as a cut-off for all species and echinocandins. All non-WT isolates had high XTT MICs &gt;1 mg/L, whereas the overall inter-centre EA and CA were 72%–89% and 100%, respectively. Conclusions The XTT colorimetric assay improved the antifungal susceptibility testing of echinocandins against Aspergillus spp., reliably detecting non-WT isolates.

scholarly journals Comparative Evaluation of MIRONAUT-AM and CLSI broth microdilution method for antifungal susceptibility testing of Aspergillus species against four commonly used antifungals

2020 ◽  
Vol 58 (8) ◽  
pp. 1085-1090
Author(s):  
Ali Nuh ◽  
Newara Ramadan ◽  
Silke Schelenz ◽  
Darius Armstrong-James
Keyword(s):  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Colorimetric Method ◽  
Reference Method ◽  
Aspergillus Species ◽  
Reference Laboratory ◽  
Broth Microdilution ◽  
Suitable Alternative ◽  
Microdilution Method ◽  
Broth Microdilution Method

Abstract The aim of this study was to evaluate a colorimetric method, MIRONAUT-AM, for determining susceptibility testing of anidulafungin, amphotericin, voriconazole, and itraconazole by comparing the minimum inhibitory (effective) concentrations (MICs/MECs) obtained by this method to those generated by the reference Clinical Laboratory Standard Institute (CLSI) broth microdilution method. In sum, 78 clinical isolates of Aspergillus species, nine of them non-wild type (non-WT) with itraconazole MIC ranging from 2 mg/l to &gt;16 mg/l, were tested against above antifungals. A. fumigatus ATCC 204305 was used as a reference strain, and test was performed in accordance with slightly modified yeast susceptibility testing instruction of the manufacture; conidia suspension inoculum and alamarBlue concentration were optimized. These same isolates were referred to Bristol Mycology reference laboratory and tested by CLSI method. The MICs and MECs generated by the two methods were compared using concordance analysis. MIRONAUT-AM showed significant concordance (P &lt; .0001) with CLSI method, and overall agreement was high (≥90%). In addition, MIRONAUT-AM produced echinocandin MECs results within 18–24 hours incubation time and correctly detected all non-WT isolates except one isolate. This colorimetric method is very promising and appears to be a suitable alternative susceptibility testing method to labor intensive broth microdilution reference method for Aspergillus species.

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