In vitro susceptibility of Aspergillus and Fusarium associated with equine keratitis to new antifungal drugs

2020 ◽  
Vol 23 (5) ◽  
pp. 918-922 ◽  
Author(s):  
Darby Roberts ◽  
Henry Van T. Cotter ◽  
Marc Cubeta ◽  
Brian C. Gilger
Keyword(s):  
Antifungal Drugs ◽  
In Vitro Susceptibility

scholarly journals Comparison of NCCLS and 3-(4,5-Dimethyl-2-Thiazyl)-2,5-Diphenyl-2H-Tetrazolium Bromide (MTT) Methods of In Vitro Susceptibility Testing of Filamentous Fungi and Development of a New Simplified Method

2000 ◽  
Vol 38 (8) ◽  
pp. 2949-2954 ◽  
Author(s):  
Joseph Meletiadis ◽  
Jacques F. G. M. Meis ◽  
Johan W. Mouton ◽  
J. Peter Donnelly ◽  
Paul E. Verweij
Keyword(s):  
Filamentous Fungi ◽  
Clinical Laboratory ◽  
Colorimetric Method ◽  
Antifungal Drugs ◽  
National Committee ◽  
In Vitro Susceptibility ◽  
Initial Inoculum ◽  
Tetrazolium Bromide ◽  
Mtt Method

The susceptibility of 30 clinical isolates belonging to six different species of filamentous fungi (Aspergillus fumigatus, Aspergillus flavus, Scedosporium prolificans, Scedosporium apiospermum, Fusarium solani, and Fusarium oxysporum) was tested against six antifungal drugs (miconazole, voriconazole, itraconazole, UR9825, terbinafine, and amphotericin B) with the microdilution method recommended by the National Committee for Clinical Laboratory Standards (NCCLS) (M38-P). The MICs were compared with the MICs obtained by a colorimetric method measuring the reduction of the dye 3-(4,5-dimethyl-2-thiazyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) to formazan by viable fungi. The levels of agreement between the two methods were 96 and 92% for MIC-0 (clear wells) and MIC-1 (75% growth reduction), respectively. The levels of agreement were always higher for Aspergillus spp. (97% ± 2.5%), followed byScedosporium spp. (87% ± 10.3%) and Fusariumspp. (78% ± 7.8%). The NCCLS method was more reproducible than the MTT method: 98 versus 95% for MIC-0 and 97 versus 90% for MIC-1. However, the percentage of hyphal growth as determined visually by the NCCLS method showed several discrepancies when they were compared with the percentages of MTT reduction. A new simplified assay that incorporates the dye MTT with the initial inoculum and in which the fungi are incubated with the dye for 48 h or more was developed, showing comparable levels of agreement and reproducibility with the other two methods. Furthermore, the new assay was easier to perform and more sensitive than the MTT method.

In vitro susceptibility of 188 clinical and environmental isolates of Aspergillus flavus for the new triazole isavuconazole and seven other antifungal drugs

Mycoses ◽  
2011 ◽  
Vol 54 (5) ◽  
pp. e583-e589 ◽  
Author(s):  
M. R. Shivaprakash ◽  
Erik Geertsen ◽  
Arunaloke Chakrabarti ◽  
Johan W. Mouton ◽  
Jacques F. Meis
Keyword(s):  
Aspergillus Flavus ◽  
Antifungal Drugs ◽  
Environmental Isolates ◽  
In Vitro Susceptibility

scholarly journals Molecular Studies Reveal Frequent Misidentification of Aspergillus fumigatus by Morphotyping

2006 ◽  
Vol 5 (10) ◽  
pp. 1705-1712 ◽  
Author(s):  
S. Arunmozhi Balajee ◽  
David Nickle ◽  
Janos Varga ◽  
Kieren A. Marr
Keyword(s):  
Aspergillus Fumigatus ◽  
Amphotericin B ◽  
Distinct Species ◽  
Enzyme Polymorphism ◽  
Antifungal Drugs ◽  
Clinical Isolates ◽  
Polymorphism Analysis ◽  
In Vitro Susceptibility ◽  
Epidemiological Surveys

ABSTRACT Aspergillus fumigatus has been understood to be the most common cause of invasive aspergillosis (IA) in all epidemiological surveys. However, recent studies have uncovered a large degree of genetic heterogeneity between isolates morphologically identified as A. fumigatus, leading to the description of a new species, Aspergillus lentulus. Here, we examined the genetic diversity of clinical isolates identified as A. fumigatus using restriction enzyme polymorphism analysis and sequence-based identification. Analysis of 50 clinical isolates from geographically diverse locations recorded the presence of at least three distinct species: A. lentulus, Aspergillus udagawae, and A. fumigatus. In vitro, A. lentulus isolates demonstrated decreased susceptibility to antifungal drugs currently used for IA, including amphotericin B, voriconazole, and caspofungin; A. udagawae isolates demonstrated decreased in vitro susceptibility to amphotericin B. Results of the present study demonstrate that current phenotypic methods to identify fungi do not differentiate between genetically distinct species in the A. fumigatus group. Differential antifungal susceptibilities of these species may account for some of the reported poor outcomes of therapy in clinical studies.

scholarly journals Phenotypic aspects of oral strains of Candida albicans in children with down's syndrome

2006 ◽  
Vol 66 (3) ◽  
pp. 939-944 ◽  
Author(s):  
E. L. Ribeiro ◽  
M. L. Scroferneker ◽  
M. S. Cavalhaes ◽  
C. C. Campos ◽  
G. M. Nagato ◽  
...  
Keyword(s):  
Inhibitory Concentration ◽  
Down's Syndrome ◽  
Test Group ◽  
Down’S Syndrome ◽  
Antifungal Drugs ◽  
Control Group ◽  
Broth Microdilution ◽  
In Vitro Susceptibility ◽  
Biological Aspects

The aim of this article is to characterize the biological aspects of oral strains of C. albicans in children with Down's syndrome. These yeasts were analyzed as to their macromorphological and enzymatic aspects and were tested as to their in vitro susceptibility to antifungal drugs using broth microdilution to determine the minimum inhibitory concentration (MIC). The morphotyping revealed that all oral C. albicans isolates from children with Down's syndrome promoted the formation of fringes regardless of size, while the control group presented smaller fringes. All oral C. albicans strains produced proteinase, but those with phospholipolytic activity showed greater enzyme capacity in the test group. In vitro susceptibility showed that all oral C. albicans isolates were sensitive to the drugs used.

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.

scholarly journals Effect of Prolonged Fluconazole Treatment on Candida albicans in Diffusion Chambers Implanted into Mice

2002 ◽  
Vol 46 (10) ◽  
pp. 3175-3179
Author(s):  
Peter G. Sohnle ◽  
Beth L. Hahn
Keyword(s):  
Candida Albicans ◽  
Inflammatory Response ◽  
Inflammatory Cells ◽  
Model System ◽  
Antifungal Drugs ◽  
Yeast Cells ◽  
In Vitro Susceptibility ◽  
Bonferroni Test

ABSTRACT Fluconazole is an azole agent with primarily fungistatic activity in standard in vitro susceptibility tests. The present study was undertaken to develop a diffusion chamber model system in mice in order to study the in vivo effects of prolonged fluconazole treatment on Candida albicans. Chambers containing 100 C. albicans yeast cells were implanted subcutaneously on the flanks of C57BL/6 mice and were then retrieved 6 or 14 weeks later (after fluconazole treatment for 4 or 12 weeks, respectively). Leukocyte counts demonstrated that implantation of the chambers did elicit an inflammatory response but that only small numbers of inflammatory cells were able to enter the chamber interior. Treatment with fluconazole at 10 mg/kg of body weight/day for 12 weeks not only reduced the numbers of viable organisms within the chambers compared to those in untreated mice (mean ± standard deviation of log10 CFU of 0.7 ± 1.2 versus 2.3 ± 2.0; P < 0.001 by the Bonferroni test) but also increased the numbers of chambers that became sterile over the treatment period (14 of 16 versus 6 of 19; P = 0.0009 by the chi-square test). However, treatment for only 4 weeks had minimal effects on the numbers of chamber CFU, and none of the chambers became sterile during this period. Distribution of retrieved organisms between interior fluid and the chamber filters was approximately equal in all the treatment groups. This model system appears to be useful for evaluating the effects of antifungal drugs over prolonged periods in vivo. Its use in the present study demonstrates that fluconazole can increase the rate of sterilization of C. albicans foci that are protected from the host's inflammatory response.

scholarly journals Molecular typing and in vitro antifungal susceptibility of Cryptococcus spp from patients in Midwest Brazil

2014 ◽  
Vol 8 (08) ◽  
pp. 1037-1043 ◽  
Author(s):  
Olivia Cometti Favalessa ◽  
Daphine Ariadne Jesus De Paula ◽  
Valeria Dutra ◽  
Luciano Nakazato ◽  
Tomoko Tadano ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Fungal Infections ◽  
Antifungal Susceptibility ◽  
Cryptococcus Gattii ◽  
Antifungal Drugs ◽  
Northeastern Brazil ◽  
In Vitro Susceptibility ◽  
Mato Grosso ◽  
Hiv Negative

Introduction: Cryptococcosis is a systemic fungal infection that affects humans and animals, mainly due to Cryptococcus neoformans and Cryptococcus gattii. Following the epidemic of acquired immunodeficiency syndrome (AIDS), fungal infections by C. neoformans have become more common among immunocompromised patients. Cryptococcus gattii has primarily been isolated as a primary pathogen in healthy hosts and occurs endemically in northern and northeastern Brazil. We to perform genotypic characterization and determine the in vitro susceptibility profile to antifungal drugs of the Cryptococcus species complex isolated from HIV-positive and HIV-negative patients attended at university hospitals in Cuiabá, MT, in the Midwestern region of Brazil. Methodology: Micromorphological features, chemotyping with canavanine-glycine-bromothymol blue (CGB) agar and genotyping by URA5-RFLP were used to identify the species. The antifungal drugs tested were amphotericin B, fluconazole, flucytosine, itraconazole and voriconazole. Minimum inhibitory concentrations (MICs) were determined according to the CLSI methodology M27-A3. Results: Analysis of samples yelded C. neoformans AFLP1/VNI (17/27, 63.0%) and C. gattii AFLP6/VGII (10/27, 37.0%). The MICs ranges for the antifungal drugs were: amphotericin B (0.5-1 mg/L), fluconazole (1-16 mg/L), flucytosine (1-16 mg/L), itraconazole (0.25-0.12 mg/L) and voriconazole (0.06-0.5 mg/L). Isolates of C. neoformans AFLP1/VNI were predominant in patients with HIV/AIDS, and C. gattii VGII in HIV-negative patients. The genotypes identified were susceptible to the antifungal drugs tested. Conclusion: It is worth emphasizing that AFLP6/VGII is a predominant genotype affecting HIV-negative individuals in Cuiabá. These findings serve as a guide concerning the molecular epidemiology of C. neoformans and C. gattii in the State of Mato Grosso.

scholarly journals Scedosporium spp. from Clinical Setting in Argentina, with the Proposal of the New Pathogenic Species Scedosporium americanum

2021 ◽  
Vol 7 (3) ◽  
pp. 160
Author(s):  
Ruben A. Abrantes ◽  
Nicolás Refojo ◽  
Alejandra I. Hevia ◽  
Julián Fernández ◽  
Guillermina Isla ◽  
...  
Keyword(s):  
Antifungal Drugs ◽  
Phenotypic Characterization ◽  
Clinical Samples ◽  
Phylogenetic Study ◽  
Reference Laboratory ◽  
In Vitro Susceptibility ◽  
Wide Range ◽  
Human Infections ◽  
Scedosporium Species

Species of the genus Scedosporium (family Microascaceae, phylum Ascomycota) are responsible for a wide range of opportunistic human infections, and have a low susceptibility to most antifungal drugs. It is well known that the pattern of Scedosporium species distribution varies according to geographic region. To assess the diversity of Scedosporium species in Argentina involved in human infections, we carried out a retrospective study reviewing 49 strains from clinical samples sent for diagnosis to the National Clinical Mycology Reference Laboratory between 1985 and 2019. Then, a phenotypic characterization, a phylogenetic study and and in vitro susceptibility test to antifungals were carried out. An analysis of combined nucleotide sequences dataset of the internal transcribed spacer of the ribosomal DNA (ITS) and of a fragment of the β-tubulin gene (BT2) demonstrated that 92 % of the strains belonged to the species S. boydii, S. apiospermum and S. angustum, all them pertaining to S. apiospermum species complex. However, two strains (4%) were identified as S. aurantiacum, a species never reported in clinical settings in the Americas’. Surprisingly, one of them displayed a polycytella-like conidiogenesis, up to date only reported for S. apiospermum. In addition, the strain DMic 165285 was phylogenetically located far away from the rest of the species, so is proposed as the novel species Scedosporium americanum. On the other hand, from all seven antifungals tested, voriconazole and posaconazole were the most active drugs against Scedosporium spp.

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