scholarly journals A Revised Species Concept for OpportunisticMucorSpecies Reveals Species-Specific Antifungal Susceptibility Profiles

2019 ◽  
Vol 63 (8) ◽  
Author(s):  
Lysett Wagner ◽  
Sybren de Hoog ◽  
Ana Alastruey-Izquierdo ◽  
Kerstin Voigt ◽  
Oliver Kurzai ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Susceptibility Testing ◽  
Species Concept ◽  
Antifungal Susceptibility ◽  
Content Type ◽  
Mucor Indicus ◽  
Species Specific ◽  
Susceptibility Profiles ◽  
High Mics

ABSTRACTRecently, the species concept of opportunisticMucor circinelloidesand its relatives has been revised, resulting in the recognition of its classical formae as independent species and the description of new species. In this study, we used isolates of all clinically relevantMucorspecies and performed susceptibility testing using the EUCAST reference method to identify potential species-specific susceptibility patterns.In vitrosusceptibility profiles of 101 mucoralean strains belonging to the genusMucor(72), the closely related speciesCokeromyces recurvatus(3),Rhizopus(12),Lichtheimia(10), andRhizomucor(4) to six antifungals (amphotericin B, natamycin, terbinafine, isavuconazole, itraconazole, and posaconazole) were determined. The most active drug for all Mucorales was amphotericin B. Antifungal susceptibility profiles of pathogenicMucorspecies were specific for isavuconazole, itraconazole, and posaconazole. The species formerly united inM. circinelloidesshowed clear differences in their antifungal susceptibilities.Cokeromyces recurvatus,Mucor ardhlaengiktus,Mucor lusitanicus(M. circinelloidesf.lusitanicus), andMucor ramosissimusexhibited high MICs to all azoles tested.Mucor indicuspresented high MICs for isavuconazole and posaconazole, andMucor amphibiorumandMucor irregularisshowed high MICs for isavuconazole. MIC values ofMucorspp. for posaconazole, isavuconazole, and itraconazole were high compared to those forRhizopusand the Lichtheimiaceae (LichtheimiaandRhizomucor). Molecular identification combined within vitrosusceptibility testing is recommended forMucorspecies, especially if azoles are applied in treatment.

scholarly journals Multicentric Analysis of the Species Distribution and Antifungal Susceptibility of Cryptic Isolates from Aspergillus Section Fumigati

2020 ◽  
Vol 64 (12) ◽  
Author(s):  
S. Imbert ◽  
A. C. Normand ◽  
S. Cassaing ◽  
F. Gabriel ◽  
L. Kristensen ◽  
...  
Keyword(s):  
Cryptic Species ◽  
Amphotericin B ◽  
Species Distribution ◽  
Concentration Gradient ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Content Type ◽  
Species Specific ◽  
High Mics ◽  
Aspergillus Section

ABSTRACT The antifungal susceptibility of Aspergillus cryptic species is poorly known. We assessed 51 isolates, belonging to seven Fumigati cryptic species, by the EUCAST reference method and the concentration gradient strip (CGS) method. Species-specific patterns were observed, with high MICs for azole drugs, except for Aspergillus hiratsukae and Aspergillus tsurutae, and high MICs for amphotericin B for Aspergillus lentulus and Aspergillus udagawae. Essential and categorical agreements between EUCAST and CGS results were between 53.3 and 93.3%.

scholarly journals Genetic Diversity and In Vitro Antifungal Susceptibility of 200 Clinical and Environmental Aspergillus flavus Isolates

2017 ◽  
Vol 61 (5) ◽  
Author(s):  
Mojtaba Taghizadeh-Armaki ◽  
Mohammad Taghi Hedayati ◽  
Saham Ansari ◽  
Saeed Mahdavi Omran ◽  
Sasan Saber ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Aspergillus Flavus ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Content Type ◽  
Microdilution Method ◽  
Microsatellite Genotype ◽  
Broth Microdilution Method ◽  
In Vitro Antifungal Susceptibility

ABSTRACT Aspergillus flavus has been frequently reported as the leading cause of invasive aspergillosis in certain tropical and subtropical countries. Two hundred A. flavus strains originating from clinical and environmental sources and collected between 2008 and 2015 were phylogenetically identified at the species level by analyzing partial β-tubulin and calmodulin genes. In vitro antifungal susceptibility testing was performed against antifungals using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) broth microdilution method. In addition, genotyping was performed using a short-tandem-repeat (STR) assay of a panel of six microsatellite markers (A. flavus 2A, 2B, 2C, 3A, 3B, and 3C), in order to determine the genetic variation and the potential relationship between clinical and environmental isolates. The geometric means of the minimum inhibitory concentrations/minimum effective concentrations (MICs/MECs) of the antifungals across all isolates were (in increasing order): posaconazole, 0.13 mg/liter; anidulafungin, 0.16 mg/liter; itraconazole, 0.29 mg/liter; caspofungin, 0.42 mg/liter; voriconazole, 0.64 mg/liter; isavuconazole, 1.10 mg/liter; amphotericin B, 3.35 mg/liter; and flucytosine, 62.97 mg/liter. All of the clinical isolates were genetically different. However, an identical microsatellite genotype was found between a clinical isolate and two environmental strains. In conclusion, posaconazole and anidulafungin showed the greatest in vitro activity among systemic azoles and echinocandins, respectively. However, the majority of the A. flavus isolates showed reduced susceptibility to amphotericin B. Antifungal susceptibility of A. flavus was not linked with the clinical or environmental source of isolation. Microsatellite genotyping may suggest an association between clinical and environmental strains, although this requires further investigation.

scholarly journals In VitroAntifungal Susceptibility Profile and Correlation of Mycelial and Yeast Forms of Molecularly Characterized Histoplasma capsulatum Strains from India

2014 ◽  
Vol 58 (9) ◽  
pp. 5613-5616 ◽  
Author(s):  
Shallu Kathuria ◽  
Pradeep K. Singh ◽  
Jacques F. Meis ◽  
Anuradha Chowdhary
Keyword(s):  
Amphotericin B ◽  
Susceptibility Testing ◽  
Histoplasma Capsulatum ◽  
Antifungal Susceptibility ◽  
Dimorphic Fungus ◽  
Content Type ◽  
Yeast Form ◽  
Disseminated Histoplasmosis ◽  
Susceptibility Profiles ◽  
Good Agreement

ABSTRACTThe antifungal susceptibility profiles of the mycelial and yeast forms of 23Histoplasma capsulatumstrains from pulmonary and disseminated histoplasmosis patients in India are reported here. The MIC data of this dimorphic fungus had good agreement between both forms for azoles, amphotericin B, and caspofungin. Therefore, the use of mycelial inocula forH. capsulatumantifungal susceptibility testing is suggested, which is less time-consuming vis-à-vis the yeast form, which requires 6 to 8 weeks for conversion.

scholarly journals Comparison of MIC Test Strip and Sensititre YeastOne with the CLSI and EUCAST Broth Microdilution Reference Methods for In Vitro Antifungal Susceptibility Testing of Cryptococcus neoformans

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Fatima Zohra Delma ◽  
Abdullah M. S. Al-Hatmi ◽  
Jochem B. Buil ◽  
Hein van der Lee ◽  
Marlou Tehupeiory-Kooreman ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Test Strip ◽  
Error Rates ◽  
Broth Microdilution ◽  
Content Type ◽  
In Vitro Antifungal Susceptibility

ABSTRACT We compared MIC test strip (MTS) and Sensititre YeastOne (SYO) methods with EUCAST and CLSI methods for amphotericin B, 5-fluocytosine, fluconazole, voriconazole, and isavuconazole against 106 Cryptococcus neoformans isolates. The overall essential agreement between the EUCAST and CLSI methods was >72% and >94% at ±1 and ±2 dilutions, respectively. The essential agreements between SYO and EUCAST/CLSI for amphotericin B, 5-flucytosine, fluconazole, and voriconazole were >89/>93% and between MTS and EUCAST/CLSI were >57/>75%. Very major error rates were low for amphotericin B and fluconazole (<3%) and a bit higher for the other drugs (<8%).

Antifungal susceptibility of bloodstream yeasts isolated at a public children’s hospital in Brazil: comparison of the Etest® and the AFST–EUCAST microdilution method

2007 ◽  
Vol 53 (12) ◽  
pp. 1300-1306 ◽  
Author(s):  
Flávia E. Matsumoto ◽  
Amanda L.T. Dias ◽  
Márcia S.C. Melhem ◽  
Maria W. Szeszs ◽  
Marcos E. Auler ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Candida Spp ◽  
In Vitro Susceptibility ◽  
Microdilution Method ◽  
Susceptibility Tests ◽  
Susceptibility Profiles

This study compared the minimum inhibitory concentration (MIC) results from the proposed standard methods of the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antibiotic Susceptibility Testing (AFST–EUCAST) with the commercial system Etest® in the evaluation of susceptibility to flucytosine, fluconazole, itraconazole, voriconazole, and amphotericin B of 136 Candida spp. isolated from the blood of hospitalized children. The results presented a greater agreement among Etest® MICs ±2 log2 dilutions of AFST–EUCAST for fluconazole (98.1% and 96.3%) and voriconazole (100% and 100%) for Candida albicans and Candida parapsilosis . For Candida glabrata , the agreement was greater only for fluconazole (81.8%) and voriconazole (100%). For amphotericin B, the agreement between the methods was low for all species. The agreement percentage among the Etest® and AFST–EUCAST susceptibility profiles was high according to the MIC breakpoints recommended by the M27-A2 protocol for the majority of the yeasts, except for fluconazole and itraconazole against Candida tropicalis and for itraconazole against C. glabrata and Candida krusei . According to both methodologies, a great number of Candida spp. isolates showed an in vitro susceptibility to all evaluated antifungal agents. Overall, both procedures can be reliable techniques for susceptibility tests of yeasts, but the assessment of interlaboratory agreement and correlation of MICs by different methods with in vivo response are of great importance.

scholarly journals Antifungal Susceptibility of the Aspergillus viridinutans Complex: Comparison of Two In Vitro Methods

2018 ◽  
Vol 62 (4) ◽  
pp. e01927-17 ◽  
Author(s):  
Pavlina Lyskova ◽  
Vit Hubka ◽  
Lucie Svobodova ◽  
Vanessa Barrs ◽  
Navneet K. Dhand ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Species Complex ◽  
Susceptibility Testing ◽  
Geometric Mean ◽  
Antifungal Susceptibility ◽  
Intrinsic Resistance ◽  
Content Type ◽  
In Vitro Methods ◽  
Significant Difference

ABSTRACT Cryptic species of Aspergillus fumigatus, including the Aspergillus viridinutans species complex, are increasingly reported to be causes of invasive aspergillosis. Their identification is clinically relevant, as these species frequently have intrinsic resistance to common antifungals. We evaluated the susceptibilities of 90 environmental and clinical isolates from the A. viridinutans species complex, identified by DNA sequencing of the calmodulin gene, to seven antifungals (voriconazole, posaconazole, itraconazole, amphotericin B, anidulafungin, micafungin, and caspofungin) using the reference European Committee on Antimicrobial Susceptibility Testing (EUCAST) method. The majority of species demonstrated elevated MICs of voriconazole (geometric mean [GM] MIC, 4.46 mg/liter) and itraconazole (GM MIC, 9.85 mg/liter) and had variable susceptibility to amphotericin B (GM MIC, 2.5 mg/liter). Overall, the MICs of posaconazole and the minimum effective concentrations of echinocandins were low. The results obtained by the EUCAST method were compared with the results obtained with Sensititre YeastOne (YO) panels. Overall, there was 67% agreement (95% confidence interval [CI], 62 to 72%) between the results obtained by the EUCAST method and those obtained with YO panels when the results were read at 48 h and 82% agreement (95% CI, 78 to 86%) when the results were read at 72 h. There was a significant difference in agreement between antifungals; agreement was high for amphotericin B, voriconazole, and posaconazole (70 to 86% at 48 h and 88 to 93% at 72 h) but was very low for itraconazole (37% at 48 h and 57% at 72 h). The agreement was also variable between species, with the maximum agreement being observed for A. felis isolates (85 and 93% at 48 and 72 h, respectively). Elevated MICs of voriconazole and itraconazole were cross-correlated, but there was no correlation between the other azoles tested.

scholarly journals Large-Scale Evaluation of In Vitro Amphotericin B, Triazole, and Echinocandin Activity against Coccidioides Species from U.S. Institutions

2017 ◽  
Vol 61 (4) ◽  
Author(s):  
George R. Thompson ◽  
Bridget M. Barker ◽  
Nathan P. Wiederhold
Keyword(s):  
Amphotericin B ◽  
Patient Outcomes ◽  
Large Scale ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Clinical Isolates ◽  
Content Type ◽  
Scale Evaluation ◽  
Large Scale Testing

ABSTRACT Large-scale testing of Coccidioides isolates has not been performed, and the frequency of clinical isolates with elevated amphotericin B or triazole MICs has not been evaluated. Coccidioides isolates (n = 581) underwent antifungal susceptibility testing. Elevated MIC values were observed for fluconazole (≥16 μg/ml, 37.3% of isolates; ≥32 μg/ml, 7.9% of isolates), itraconazole (≥2 μg/ml, 1.0% of isolates), posaconazole (≥1 μg/ml, 1.0% of isolates), and voriconazole (≥2 μg/ml, 1.2% of isolates). However, mold-active triazoles exhibited low MICs for the majority of isolates tested. Additional correlation with patient outcomes to determine the relevance of elevated MICs in Coccidioides isolates is needed.

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.

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 Molecular Identification and Antifungal Susceptibility of Yeast Isolates Causing Fungemia Collected in a Population-Based Study in Spain in 2010 and 2011

2013 ◽  
Vol 58 (3) ◽  
pp. 1529-1537 ◽  
Author(s):  
Jesús Guinea ◽  
Óscar Zaragoza ◽  
Pilar Escribano ◽  
Estrella Martín-Mazuelos ◽  
Javier Pemán ◽  
...  
Keyword(s):  
Hot Spot ◽  
Antifungal Susceptibility ◽  
Point Mutations ◽  
Population Based ◽  
Candida Guilliermondii ◽  
Population Based Study ◽  
Content Type ◽  
Candida Lusitaniae ◽  
Species Specific

ABSTRACTWe report the molecular identifications and antifungal susceptibilities of the isolates causing fungemia collected in the CANDIPOP population-based study conducted in 29 Spanish hospitals. A total of 781 isolates (from 767 patients, 14 of them having mixed fungemia) were collected. The species found most frequently wereCandida albicans(44.6%),Candida parapsilosis(24.5%),Candida glabrata(13.2%),Candida tropicalis(7.6%),Candida krusei(1.9%),Candida guilliermondii(1.7%), andCandida lusitaniae(1.3%). OtherCandidaand non-Candidaspecies accounted for approximately 5% of the isolates. The presence of cryptic species was low. Compared to findings of previous studies conducted in Spain, the frequency ofC. glabratahas increased. Antifungal susceptibility testing was performed by using EUCAST and CLSI M27-A3 reference procedures; the two methods were comparable. The rate of fluconazole-susceptible isolates was 80%, which appears to be a decrease compared to findings of previous studies, explained mainly by the higher frequency ofC. glabrata. Using the species-specific breakpoints and epidemiological cutoff values, the rate of voriconazole and posaconazolein vitroresistance was low (<2%). In the case ofC. tropicalis, using the EUCAST procedure, the rate of azole resistance was around 20%. There was a correlation between the previous use of azoles and the presence of fluconazole-resistant isolates. Resistance to echinocandins was very rare (2%), and resistance to amphotericin B also was very uncommon. The sequencing of the hot spot (HS) regions fromFKS1orFKS2genes in echinocandin-resistant isolates revealed previously described point mutations. The decrease in the susceptibility to fluconazole in Spanish isolates should be closely monitored in future studies.

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