scholarly journals Colistin and Isavuconazole Interact Synergistically In Vitro against Aspergillus nidulans and Aspergillus niger

2020 ◽  
Vol 8 (9) ◽  
pp. 1447
Author(s):  
Patrick Schwarz ◽  
Elie Djenontin ◽  
Eric Dannaoui
Keyword(s):  
Aspergillus Niger ◽  
Aspergillus Nidulans ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Important Species ◽  
Agar Diffusion ◽  
Agar Diffusion Assay ◽  
Diffusion Assay

The in vitro interactions of isavuconazole in combination with colistin were evaluated against 55 clinical Aspergillus species isolates belonging to the five most important species (Aspergillus flavus, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, and Aspergillus terreus) responsible for human aspergillosis by a microdilution checkerboard technique based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) reference method for antifungal susceptibility testing. Selected isolates (A. nidulans, n = 10; A. niger, n = 15) were additionally evaluated by an agar diffusion assay using isavuconazole gradient concentration strips with or without colistin incorporated Roswell Parc Memorial Institute (RPMI) agar. Interpretation of the checkerboard results was done by the fractional inhibitory concentration index. Using the checkerboard method, combination isavuconazole–colistin was synergistic for 100% of the 15 A. nidulans isolates and for 60% of the 20 A. niger isolates. No interactions were found for any of the other isolates. By agar diffusion assay, minimal inhibitory concentrations (MICs) in combination decreased compared to isavuconazole alone for 92% of the isolates. No interactions were found for any A. nidulans isolates, but synergy was observed for 40% of the A. niger isolates. A poor essential agreement of EUCAST and gradient concentration strip MICs at ± 2 log2 dilutions with 0% was obtained. Antagonistic interactions were never observed regardless of the technique used.

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 Vitro Interaction between Isavuconazole and Tacrolimus, Cyclosporin A, or Sirolimus against Aspergillus Species

2020 ◽  
Vol 6 (3) ◽  
pp. 103 ◽  
Author(s):  
Patrick Schwarz ◽  
Eric Dannaoui
Keyword(s):  
Cyclosporin A ◽  
Aspergillus Terreus ◽  
Susceptibility Testing ◽  
Inhibitory Concentration ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Common Species ◽  
Minimal Inhibitory Concentrations ◽  
In Vitro Interaction

The interaction of isavuconazole with immunosuppressors (tacrolimus, cyclosporin A, or sirolimus) against 30 Aspergillus isolates belonging to the most common species responsible for invasive aspergillosis in humans (Aspergillus flavus, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, and Aspergillus terreus) was evaluated in vitro by a microdilution checkerboard technique based on the EUCAST reference method for antifungal susceptibility testing. The interpretation of the results was performed based on the fractional inhibitory concentration index. The combination of isavuconazole with tacrolimus, cyclosporin A, or sirolimus, was synergistic for 56, 20, or 10% of the isolates, respectively. Interestingly synergy of the combination of isavuconazole with tacrolimus was also achieved for the majority of azole-resistant isolates of A. fumigatus, and for all A. niger isolates with isavuconazole minimal inhibitory concentrations ≥ 8 µg/mL. Antagonistic interactions were never observed for any combination tested.

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.

In Vitro Antifungal Activity of Several Antimicrobial Compounds against Penicillium expansum

2002 ◽  
Vol 65 (5) ◽  
pp. 834-839 ◽  
Author(s):  
M. E. VENTURINI ◽  
D. BLANCO ◽  
R. ORIA
Keyword(s):  
Hydrogen Peroxide ◽  
Antimicrobial Activity ◽  
Prevention And Control ◽  
Penicillium Expansum ◽  
Agar Diffusion ◽  
Agar Diffusion Assay ◽  
And Control ◽  
Diffusion Assay ◽  
Broth Dilution

Fungicides used in the prevention and control of mold rots in stored apples are subjected to legal, social, and biological limitations. The aim of this study was to find an alternative to postharvest fungicides currently used in the prevention and control of blue mold rot caused by Penicillium expansum in apples. For this purpose, the antimicrobial activity and MIC of several substances against P. expansum were evaluated in vitro using different end point methods: agar diffusion assay, volatility method, and agar dilution and broth dilution MIC assays. Most of the substances tested are common food ingredients and have a recognized antimicrobial activity. Essential oils, such as thymol, eugenol, citral and cineole, vanillin, sodium hypochlorite, acetic acid, potassium sorbate, and hydrogen peroxide, were the substances evaluated. Thymol and citral were the essential oil components that showed the greatest inhibitory effects. The effectiveness of 5 and 10% hydrogen peroxide in growth inhibition of P. expansum in the agar diffusion assay was total, and its MIC as determined by the agar and broth dilution assays was less than 0.025%. These results indicate that the application of small quantities of hydrogen peroxide to the apple skin might be an alternative to fungicides in the elimination of P. expansum.

Clinical and Microbiological Evaluation of the Carious Dentin Before and After Application of Papacarie Gel

2013 ◽  
Vol 38 (2) ◽  
pp. 133-138 ◽  
Author(s):  
S Gupta ◽  
C Singh ◽  
Y Ramakrishna ◽  
K Chaudhry ◽  
AK Munshi
Keyword(s):  
Primary Teeth ◽  
Patient Comfort ◽  
Permanent Teeth ◽  
Agar Diffusion ◽  
Before And After ◽  
Caries Removal ◽  
Agar Diffusion Assay ◽  
Caries Excavation ◽  
Diffusion Assay

Objective: To evaluate clinically and microbiologically the efficacy of Papacarie® in the removal of carious dentin in both permanent and primary teeth. Study design: Thirty permanent and primary molars with dentinal carious lesions were excavated and subjected to clinical and microbiological assessment before and after application of Papacarie®. The gel was further tested for in vitro antimicrobial efficacy against standard cariogenic micro-organisms using agar diffusion assay. Results: Papacarie® was able to differentiate between infected and affected dentin clinically along with high patient comfort during caries excavation. The mean time taken for caries removal and restoration was observed to be 4.17 ± 0.40 min. and 8.57 ± 0.45 min. for permanent teeth and 4.21 ± 0.36 min. and 9.24 ± 0.58 min. for primary teeth. There was a significant reduction in the total viable colony forming units from the dentin samples before and after application of Papacarie®. It was also observed that Papacarie® had no inhibitory effect on standard cariogenic microorganisms in the agar diffusion assay. Conclusions: Papacarie® is an effective caries removal method clinically in both permanent and primary teeth. The number of viable microorganisms after complete caries excavation using Papacarie® still appears to be high and this bacterial count should be tackled by a suitable restorative material with potent antimicrobial activity.

scholarly journals Antifungal Susceptibility Testing of Dermatophytes: Establishing a Medium for Inducing Conidial Growth and Evaluation of Susceptibility of Clinical Isolates

2000 ◽  
Vol 38 (1) ◽  
pp. 341-344
Author(s):  
C. J. Jessup ◽  
J. Warner ◽  
N. Isham ◽  
I. Hasan ◽  
M. A. Ghannoum
Keyword(s):  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Antifungal Susceptibility Testing ◽  
Optimal Conditions ◽  
In Vitro Susceptibility ◽  
Conidial Formation ◽  
The Mean ◽  
Optimal Medium

ABSTRACT A standardized reference method for dermatophyte in vitro susceptibility testing is lacking. In a previous study, Norris et al. (H. A. Norris, B. E. Elewski, and M. A. Ghannoum, J. Am. Acad. Dermatol. 40(6, part 2):S9–S13) established the optimal medium and other growth variables. However, the earlier study did not address two issues: (i) selection of an optimal medium for conidial formation by dermatophytes and (ii) validation of the method with a large number of dermatophytes. The present study addresses these two points. To select which agar medium best supported conidial growth, representative isolates of dermatophytes were grown on different agars. Preliminary experiments showed that only oatmeal cereal agar supported the production of conidia by Trichophyton rubrum . We tested the abilities of 251 T. rubrum isolates to form conidia using three different cereal agars and potato dextrose agar. Overall, oatmeal cereal and rice agar media were comparable in their abilities to support T. rubrum conidial growth. Next, we used the oatmeal cereal agar for conidial formation along with the optimal conditions for dermatophyte susceptibility testing proposed by Norris et al. and determined the antifungal susceptibilities of 217 dermatophytes to fluconazole, griseofulvin, itraconazole, and terbinafine. Relative to the other agents tested, terbinafine possessed the highest antifungal activity against all of the dermatophytes. The mean ± standard error of the mean MICs of fluconazole, itraconazole, terbinafine, and griseofulvin were 2.07 ± 0.29, 0.13 ± 0.01, 0.002 ± 0.0003, and 0.71 ± 0.05 μg/ml, respectively. This study is the first step in the identification of optimal conditions that could be used for the standardization of the antifungal susceptibility testing method for dermatophytes. Inter- and intralaboratory agreement as well as clinical correlations need to be established.

scholarly journals Etest and Sensititre YeastOne Susceptibility Testing of Echinocandins against Candida Species from a Single Center in Austria

2017 ◽  
Vol 61 (8) ◽  
Author(s):  
Maria Aigner ◽  
Thomas Erbeznik ◽  
Martin Gschwentner ◽  
Cornelia Lass-Flörl
Keyword(s):  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Broth Microdilution ◽  
Content Type ◽  
Testing Susceptibility ◽  
Clinical Breakpoints ◽  
Echinocandin Resistance ◽  
Species Specific

ABSTRACT Candida species were tested for susceptibility to caspofungin, anidulafungin, and micafungin in order to evaluate the roles of Etest and Sensititre YeastOne in antifungal susceptibility testing for daily routines and to survey resistance. A total of 104 Candida species isolates detected from blood cultures were investigated. With EUCAST broth microdilution as the reference method, essential agreement (EA), categorical agreement (CA), very major errors (VME), major errors (ME), and minor (MIN) errors were assessed by reading MICs at 18, 24, and 48 h. By use of EUCAST broth microdilution and species-specific clinical breakpoints (CBPs), echinocandin resistance was not detected during the study period. Using EUCAST CBPs, MIC readings at 24 h for the Etest and Sensititre YeastOne resulted in CA levels of 99% and 93% for anidulafungin and 99% and 97% for micafungin. Using revised CLSI CBPs for caspofungin, CA levels were 92% and 99% for Etest and Sensititre YeastOne. The Etest proved an excellent, easy-to-handle alternative method for testing susceptibility to anidulafungin and micafungin. Due to misclassifications, the Etest is less suitable for testing susceptibility to caspofungin (8% of isolates falsely tested resistant). The CA levels of Sensititre YeastOne were 93% and 97% for anidulafungin and micafungin (24 h) by use of EUCAST CBPs and increased to 100% for both antifungals if CLSI CBPs were applied and to 100% and 99% if Sensititre YeastOne epidemiological cutoff values (ECOFFs) were applied. No one echinocandin could be demonstrated to be superior to another in vitro. Since resistance was lacking among our Candida isolates, we cannot derive any recommendation from accurate resistance detection by the Etest and Sensititre YeastOne.

scholarly journals Comparative Evaluation of Sensititre YeastOne and CLSI M38-A2 Reference Method for Antifungal Susceptibility Testing of Aspergillus spp. against Echinocandins

2017 ◽  
Vol 55 (6) ◽  
pp. 1714-1719 ◽  
Author(s):  
Maria Siopi ◽  
Spyros Pournaras ◽  
Joseph Meletiadis
Keyword(s):  
Aspergillus Fumigatus ◽  
Comparative Evaluation ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Antifungal Susceptibility Testing ◽  
Content Type

ABSTRACT Sensititre YeastOne (YO) panels were assessed for in vitro susceptibility testing of echinocandins against 39 isolates of Aspergillus fumigatus , A. flavus , and A. terreus , including two echinocandin-resistant A. fumigatus strains, using different inocula (10 3 , 10 4 , and 10 5 CFU/ml), incubation times (16 to 48 h), and endpoints (first blue or purple well) and compared to CLSI M38-A2. The best agreement was found with an inoculum of 10 4 CFU/ml, incubation times of 20 h for A. flavus and of 30 h for A. fumigatus and A. terreus , and reading the first purple well. The reproducibility within ±1 2-fold dilutions was 100% for all three echinocandins. YO color endpoints were 2 to 3 2-fold dilutions lower than CLSI minimum effective concentrations (MECs) of caspofungin and 1 to 2 2-fold dilutions higher than CLSI MECs of micafungin. For anidulafungin, off-scale YO color endpoints were observed. Nevertheless, A. fumigatus echinocandin-resistant isolates were detected after 24 h of incubation.

scholarly journals Molecular Epidemiology and Antifungal Susceptibility of Trichophyton Isolates in Greece: Emergence of Terbinafine-Resistant Trichophytonmentagrophytes Type VIII Locally and Globally

2021 ◽  
Vol 7 (6) ◽  
pp. 419
Author(s):  
Maria Siopi ◽  
Ioanna Efstathiou ◽  
Konstantinos Theodoropoulos ◽  
Spyros Pournaras ◽  
Joseph Meletiadis
Keyword(s):  
Molecular Epidemiology ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Cross Resistance ◽  
Squalene Epoxidase ◽  
In Vitro Susceptibility ◽  
Type Viii ◽  
In Vitro Antifungal Susceptibility ◽  
Resistance Rates

Trichophyton isolates with reduced susceptibility to antifungals are now increasingly reported worldwide. We therefore studied the molecular epidemiology and the in vitro antifungal susceptibility patterns of Greek Trichophyton isolates over the last 10 years with the newly released EUCAST reference method for dermatophytes. Literature was reviewed to assess the global burden of antifungal resistance in Trichophyton spp. The in vitro susceptibility of 112 Trichophyton spp. molecularly identified clinical isolates (70 T. rubrum, 24 T. mentagrophytes, 12 T. interdigitale and 6 T. tonsurans) was tested against terbinafine, itraconazole, voriconazole and amorolfine (EUCAST E.DEF 11.0). Isolates were genotyped based on the internal transcribed spacer (ITS) sequences and the target gene squalene epoxidase (SQLE) was sequenced for isolates with reduced susceptibility to terbinafine. All T. rubrum, T. interdigitale and T. tonsurans isolates were classified as wild-type (WT) to all antifungals, whereas 9/24 (37.5%) T. mentagrophytes strains displayed elevated terbinafine MICs (0.25–8 mg/L) but not to azoles and amorolfine. All T. interdigitale isolates belonged to ITS Type II, while T. mentagrophytes isolates belonged to ITS Type III* (n = 11), VIII (n = 9) and VII (n = 4). All non-WT T. mentagrophytes isolates belonged to Indian Genotype VIII and harbored Leu393Ser (n = 5) and Phe397Leu (n = 4) SQLE mutations. Terbinafine resistance rates ranged globally from 0–44% for T. rubrum and 0–76% for T. interdigitale/T. mentagrophytes with strong endemicity. High incidence (37.5%) of terbinafine non-WT T. mentagrophytes isolates (all belonging to ITS Type VIII) without cross-resistance to other antifungals was found for the first time in Greece. This finding must alarm for susceptibility testing of dermatophytes at a local scale particularly in non-responding dermatophytoses.

scholarly journals The Emerging Terbinafine-Resistant Trichophyton Epidemic: What Is the Role of Antifungal Susceptibility Testing?

Dermatology ◽  
2021 ◽  
pp. 1-20
Author(s):  
Julia J. Shen ◽  
Maiken C. Arendrup ◽  
Shyam Verma ◽  
Ditte Marie L. Saunte
Keyword(s):  
Gene Mutation ◽  
Susceptibility Testing ◽  
Geometric Mean ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing ◽  
Squalene Epoxidase ◽  
Exclusion Criteria ◽  
Huge Variation

<b><i>Background:</i></b> Dermatophytosis is commonly encountered in the dermatological clinics. The main aetiological agents in dermatophytosis of skin and nails in humans are <i>Trichophyton</i> (<i>T</i>.) <i>rubrum</i>, <i>T. mentagrophytes</i> and <i>T. interdigitale</i> (former <i>T. mentagrophytes-</i>complex). Terbinafine therapy is usually effective in eradicating infections due to these species by inhibiting their squalene epoxidase (SQLE) enzyme, but increasing numbers of clinically resistant cases and mutations in the SQLE gene have been documented recently. Resistance to antimycotics is phenotypically determined by antifungal susceptibility testing (AFST). However, AFST is not routinely performed for dermatophytes and no breakpoints classifying isolates as susceptible or resistant are available, making it difficult to interpret the clinical impact of a minimal inhibitory concentration (MIC). <b><i>Summary:</i></b> PubMed was systematically searched for terbinafine susceptibility testing of dermatophytes on October 20, 2020, by two individual researchers. The inclusion criteria were <i>in vitro</i> terbinafine susceptibility testing of <i>Trichophyton (T.) rubrum</i>, <i>T. mentagrophytes</i> and <i>T. interdigitale</i> with the broth microdilution technique. The exclusion criteria were non-English written papers. Outcomes were reported as MIC range, geometric mean, modal MIC and MIC<sub>50</sub> and MIC<sub>90</sub> in which 50 or 90% of isolates were inhibited, respectively. The reported MICs ranged from &#x3c;0.001 to &#x3e;64 mg/L. The huge variation in MIC is partly explained by the heterogeneity of the <i>Trichophyton</i> isolates, where some originated from routine specimens (wild types) whereas others came from non-responding patients with a known SQLE gene mutation. Another reason for the great variation in MIC is the use of different AFST methods where MIC values are not directly comparable. High MICs were reported particularly in isolates with SQLE gene mutation. The following SQLE alterations were reported: F397L, L393F, L393S, H440Y, F393I, F393V, F415I, F415S, F415V, S443P, A448T, L335F/A448T, S395P/A448T, L393S/A448T, Q408L/A448T, F397L/A448T, I121M/V237I and H440Y/F484Y in terbinafine-resistant isolates.

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