scholarly journals Development and validation of an in vitro resazurin-based susceptibility assay against Madurella mycetomatis

2020 ◽  
pp. AAC.01338-20
Author(s):  
S. O. Abd Algaffar ◽  
A Verbon ◽  
W. W. J. van de Sande ◽  
S. A. Khalid
Keyword(s):  
Amphotericin B ◽  
Minimal Inhibitory Concentrations ◽  
Madurella Mycetomatis ◽  
Development And Validation ◽  
Susceptibility Assay

We here present an in vitro susceptibility assay for Madurella mycetomatis hyphae using resazurin for endpoint-reading. Using this assay, reproducible minimal inhibitory concentrations (MICs) were obtained for amphotericin B, itraconazole, voriconazole, posaconazole, terbinafine and micafungin. Results were comparable with XTT-based susceptibility assay. Lowest MICs were obtained for itraconazole and posaconazole (MIC50 of 0.016 μg/mL) followed by voriconazole (MIC50 of 0.063 μg/mL). Amphotericin B, micafungin, and terbinafine appeared much less effective.

scholarly journals In Vitro Susceptibilities of Madurella mycetomatis to Itraconazole and Amphotericin B Assessed by a Modified NCCLS Method and a Viability-Based 2,3-Bis(2-Methoxy-4-Nitro-5- Sulfophenyl)-5-[(Phenylamino)Carbonyl]-2H- Tetrazolium Hydroxide (XTT) Assay

2004 ◽  
Vol 48 (7) ◽  
pp. 2742-2746 ◽  
Author(s):  
Abdalla O. A. Ahmed ◽  
Wendy W. J. van de Sande ◽  
Wim van Vianen ◽  
Alex van Belkum ◽  
Ahmed H. Fahal ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Xtt Assay ◽  
Madurella Mycetomatis ◽  
Visual Reading

ABSTRACT Susceptibilities of Madurella mycetomatis against amphotericin B and itraconazole in vitro were determined by protocols based on NCCLS guidelines (visual reading) and a 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) assay for fungal viability. The XTT assay was reproducible and sensitive for both antifungals. Itraconazole (MIC at which 50% of the isolates tested are inhibited [MIC50]) of 0.06 to 0.13 mg/liter) was superior to amphotericin B (MIC50 of 0.5 to 1.0 mg/liter).

scholarly journals In vitro susceptibility to antifungal agents of clinical and environmental Cryptococcus neoformans isolated in Southern of Brazil

2001 ◽  
Vol 43 (5) ◽  
pp. 267-270 ◽  
Author(s):  
Sydney Hartz ALVES ◽  
Loiva T. OLIVEIRA ◽  
Jane M. COSTA ◽  
Irina LUBECK ◽  
Agnes Kiesling CASALI ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Clinical Isolates ◽  
Environmental Isolates ◽  
Aids Patients ◽  
In Vitro Susceptibility ◽  
Minimal Inhibitory Concentrations

The purpose of the present study was to compare the susceptibility to four antifungal agents of 69 Cryptococcus neoformans strains isolated from AIDS patients with that of 13 C. neoformans strains isolated from the environment. Based on the NCCLS M27-A methodology the Minimal Inhibitory Concentrations (MICs) obtained for amphotericin B, itraconazole and ketoconazole were very similar for clinical and environmental isolates. Clinical isolates were less susceptible to fluconazole than environmental isolates. The significance of these findings and aspects concerning the importance, role and difficulties of C. neoformans susceptibility testing are also discussed.

scholarly journals In vitro susceptibility of Paracoccidioides brasiliensis yeast form to antifungal agents

1984 ◽  
Vol 26 (6) ◽  
pp. 322-328 ◽  
Author(s):  
Angela Restrepo ◽  
Catalina de Bedoutand Angela M. Tabares
Keyword(s):  
Amphotericin B ◽  
Antifungal Agents ◽  
Inhibitory Concentration ◽  
Paracoccidioides Brasiliensis ◽  
Fractional Inhibitory Concentration ◽  
In Vitro Susceptibility ◽  
Yeast Form ◽  
Minimal Inhibitory Concentrations ◽  
Combined Use

A study was conducted to determine the susceptibility of P. brasiliensis yeast form to amphotericin B (A), ketoconazole (K), 5-fluorocytosine (5-FC) and rifampin (R). The three isolates tested produced minimal inhibitory concentrations (MICs) (mcg/ml) in the following range: A: 0.09-0.18; K: 0.001-0.007; 5-FC: 62.5-250 and R: 40-80. The minimal fungicidal concentrations (MFC) were several times higher than the corresponding MICs. Precise MFC for 5-FC were not obtained (> 500 mcg/ml). Combination of K plus A proved synergic, with the fractional inhibitory concentration (FIC) indices revealing synergy when the drugs were combined at the 1 to 1 and 1 to 5 MIC ratios. R (40 mcg/ml) appeared to antagonize K. These results indicate promise for the combined use of K plus A as a therapeutical regimen.

scholarly journals Niclosamide Is Active In Vitro against Mycetoma Pathogens

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4005
Author(s):  
Abdelhalim B. Mahmoud ◽  
Shereen Abd Algaffar ◽  
Wendy van de Sande ◽  
Sami Khalid ◽  
Marcel Kaiser ◽  
...  
Keyword(s):  
Nitro Group ◽  
Causative Agent ◽  
Drug Repurposing ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Minimal Inhibitory Concentrations ◽  
Redox Active ◽  
Causative Agents ◽  
Madurella Mycetomatis

Redox-active drugs are the mainstay of parasite chemotherapy. To assess their repurposing potential for eumycetoma, we have tested a set of nitroheterocycles and peroxides in vitro against two isolates of Madurella mycetomatis, the main causative agent of eumycetoma in Sudan. All the tested compounds were inactive except for niclosamide, which had minimal inhibitory concentrations of around 1 µg/mL. Further tests with niclosamide and niclosamide ethanolamine demonstrated in vitro activity not only against M. mycetomatis but also against Actinomadura spp., causative agents of actinomycetoma, with minimal inhibitory concentrations below 1 µg/mL. The experimental compound MMV665807, a related salicylanilide without a nitro group, was as active as niclosamide, indicating that the antimycetomal action of niclosamide is independent of its redox chemistry (which is in agreement with the complete lack of activity in all other nitroheterocyclic drugs tested). Based on these results, we propose to further evaluate the salicylanilides, niclosamidein particular, as drug repurposing candidates for mycetoma.

scholarly journals Testing of the In Vitro Susceptibilities of Madurella mycetomatis to Six Antifungal Agents by Using the Sensititre System in Comparison with a Viability-Based 2,3-Bis(2-Methoxy-4-Nitro-5-Sulfophenyl)-5- [(Phenylamino)Carbonyl]-2H-Tetrazolium Hydroxide (XTT) Assay and a Modified NCCLS Method

2005 ◽  
Vol 49 (4) ◽  
pp. 1364-1368 ◽  
Author(s):  
Wendy W. J. van de Sande ◽  
Ad Luijendijk ◽  
Abdalla O. A. Ahmed ◽  
Irma A. J. M. Bakker-Woudenberg ◽  
Alex van Belkum
Keyword(s):  
Amphotericin B ◽  
Antifungal Agents ◽  
Clinical Isolates ◽  
Therapeutic Management ◽  
Xtt Assay ◽  
Routine Testing ◽  
Antifungal Activities ◽  
Madurella Mycetomatis ◽  
Relevant Range

ABSTRACT The in vitro susceptibilities of 36 clinical isolates of Madurella mycetomatis, the prime agent of eumycetoma in Africa, to ketoconazole, itraconazole, fluconazole, voriconazole, amphotericin B, and flucytosine were determined by the Sensititre YeastOne system. This system appeared to be a rapid and easy test, and by use of hyphal suspensions it generated results comparable to those of a modified NCCLS method. After 10 days of incubation, the antifungal activities of ketoconazole (MIC at which 90% of isolates were inhibited [MIC90], 0.125 μg/ml), itraconazole (MIC90, 0.064 μg/ml), and voriconazole (MIC90, 0.125 μg/ml) appeared superior to those of fluconazole (MIC90, 128 μg/ml) and amphotericin B (MIC90, 1 μg/ml), with MICs in the clinically relevant range. All isolates were resistant to flucytosine (all MICs above 64 μg/ml). Based on the relatively broad range of MICs obtained for the antifungal agents, routine testing of M. mycetomatis isolates for susceptibility to antifungal agents seems to be relevant to adequate therapeutic management.

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