MICs measured using CLSI yeast nitrogen base (YNB) medium instead of CLSI RPMI medium for C. neoformans were evaluated. CLSI RPMI medium ECVs for distributions originating from at least three laboratories, which included >95% of the modeled WT population, were as follows: fluconazole, 8 g/ml (VNI, C. gattii nontyped, VGI, VGIIa, and VGIII), 16 g/ml (C. neoformans nontyped, VNIII, and VGIV), and 32 g/ml (VGII); itraconazole, 0.25 g/ml (VNI), 0.5 g/ml (C. neoformans and C. gattii nontyped and VGI to VGIII), and 1 g/ml (VGIV); posaconazole, 0.25 g/ml (C. neoformans nontyped and VNI) and 0.5 g/ml (C. gattii nontyped and VGI); and voriconazole, 0.12 g/ml (VNIV), 0.25 g/ml (C. neoformans and C. gattii nontyped, VNI, VNIII, VGII, and VGIIa,), and 0.5 g/ml (VGI). The number of laboratories contributing data for other molecular types was too low to ascertain that the differences were due to factors other than assay variation. In the absence of clinical breakpoints, our ECVs may aid in the detection of isolates with acquired resistance mechanisms and should be listed in the revised CLSI M27-A3 and CLSI M27-S3 documents.

rThe CLSI epidemiological cutoff values (ECVs) of antifungal agents are available for various Candida spp., Aspergillus spp., and the Mucorales. However, those categorical endpoints have not been established for Fusarium spp., mostly due to the difficulties associated with collecting sufficient CLSI MICs for clinical isolates identified according to the currently recommended molecular DNA-PCR-based identification methodologies. CLSI MIC distributions were established for 53 Fusarium dimerum species complex (SC), 10 F. fujikuroi, 82 F. proliferatum, 20 F. incarnatum-F. equiseti SC, 226 F. oxysporum SC, 608 F. solani SC, and 151 F. verticillioides isolates originating in 17 laboratories (in Argentina, Australia, Brazil, Canada, Europe, Mexico, and the United States). According to the CLSI guidelines for ECV setting, ECVs encompassing >97.5% of pooled statistically modeled MIC distributions were as follows: for amphotericin B, 4 g/ml (F. verticillioides) and 8 g/ml (F. oxysporum SC and F. solani SC); for posaconazole, 2 g/ml (F. verticillioides), 8 g/ml (F. oxysporum SC), and 32 g/ml (F. solani SC); for voriconazole, 4 g/ml (F. verticillioides), 16 g/ml (F. oxysporum SC), and 32 g/ml (F. solani SC); and for itraconazole, 32 g/ml (F. oxysporum SC and F. solani SC). Insufficient data precluded ECV definition for the other species. Although these ECVs could aid in detecting nonwild-type isolates with reduced susceptibility to the agents evaluated, the relationship between molecular mechanisms of resistance (gene mutations) and MICs still needs to be investigated for Fusarium spp.

Clinical and Laboratory Standards Institute (CLSI) conditions for testing the susceptibilities of pathogenic species to antifungal agents are based on a collaborative study that evaluated five clinically relevant isolates of and some antifungal agents. With the advent of molecular identification, there are two basic needs: to confirm the suitability of these testing conditions for all agents and species and to establish species-specific epidemiologic cutoff values (ECVs) or breakpoints (BPs) for the species. We collected available CLSI MICs/minimal effective concentrations (MECs) of amphotericin B, five triazoles, terbinafine, flucytosine, and caspofungin for 301, 486 , 75, and 13 molecularly identified isolates. Data were obtained in 17 independent laboratories (Australia, Europe, India, South Africa, and South and North America) using conidial inoculum suspensions and 48 to 72 h of incubation at 35°C. Sufficient and suitable data (modal MICs within 2-fold concentrations) allowed the proposal of the following ECVs for and , respectively: amphotericin B, 4 and 4 μg/ml; itraconazole, 2 and 2 μg/ml; posaconazole, 2 and 2 μg/ml; and voriconazole, 64 and 32 μg/ml. Ketoconazole and terbinafine ECVs for were 2 and 0.12 μg/ml, respectively. Insufficient or unsuitable data precluded the calculation of ketoconazole and terbinafine (or any other antifungal agent) ECVs for , as well as ECVs for and These ECVs could aid the clinician in identifying potentially resistant isolates (non-wild type) less likely to respond to therapy.

Rhizomucor pusillus, and 36 Syncephalastrum racemosum isolates. CLSI broth microdilution MICs were aggregated for the analyses. ECVs comprising >95% and >97.5% of the modeled populations were as follows: amphotericin B ECVs for L. corymbifera were 1 and 2 g/ml, those for M. circinelloides were 1 and 2 g/ml, those for R. arrhizus were 2 and 4 g/ml, and those for R. microsporus were 2 and 2 g/ml, respectively; posaconazole ECVs for L. corymbifera were 1 and 2, those for M. circinelloides were 4 and 4, those for R. arrhizus were 1 and 2, and those for R. microsporus were 1 and 2, respectively; both itraconazole ECVs for R. arrhizus were 2 g/ ml. ECVs may aid in detecting emerging resistance or isolates with reduced susceptibility (non-WT MICs) to the agents evaluated.

A bloodstream infection due to Candida haemulonii afflicting a patient with fever and a medical history of megaloblastic anemia is reported. The clinical isolate was misidentified by the API 20C and VITEK identification systems. The results of susceptibility tests showed that the MIC of amphotericin B for C. haemulonii was 4 g/ml. Additional susceptibility testing procedures based on the use of antibiotic medium 3 and Iso-Sensitest broth were performed, and killing curves were determined. Two collection strains of C. haemulonii were employed as controls. The three isolates exhibited resistance to amphotericin B in vitro regardless of the antifungal susceptibility testing method employed. In addition, the MICs of fluconazole for the three isolates were high. Further studies are needed in order to ascertain whether this species exhibits innate or acquired resistance to amphotericin B and other antifungal agents.

Method-dependent Etest epidemiological cutoff values (ECVs) are not available for susceptibility testing of either Candida or Aspergillus species with amphotericin B or echinocandins. In addition, reference caspofungin MICs for Candida spp. are unreliable. Candida and Aspergillus species wild-type (WT) Etest MIC distributions (microorganisms in a species-drug combination with no detectable phenotypic resistance) were established for 4,341 Candida albicans, 113 C. dubliniensis, 1,683 C. glabrata species complex (SC), 709 C. krusei, 767 C. parapsilosis SC, 796 C. tropicalis, 1,637 Aspergillus fumigatus SC, 238 A. flavus SC, 321 A. niger SC, and 247 A. terreus SC isolates. Etest MICs from 15 laboratories (in Argentina, Europe, Mexico, South Africa, and the United States) were pooled to establish Etest ECVs. Anidulafungin, caspofungin, micafungin, and amphotericin B ECVs (in micrograms per milliliter) encompassing Ն97.5% of the statistically modeled population were 0.016, 0.5, 0.03, and 1 for C. albicans; 0.03, 1, 0.03, and 2 for C. glabrata SC; 0.06, 1, 0.25, and 4 for C. krusei; 8, 4, 2, and 2 for C. parapsilosis SC; and 0.03, 1, 0.12, and 2 for C. tropicalis. The amphotericin B ECV was 0.25 g/ml for C. dubliniensis and 2, 8, 2, and 16 g/ml for the complexes of A. fumigatus, A. flavus, A. niger, and A. terreus, respectively. While anidulafungin Etest ECVs classified 92% of the Candida fks mutants evaluated as non-WT, the performance was lower for caspofungin (75%) and micafungin (84%) cutoffs. Finally, although anidulafungin (as an echinocandin surrogate susceptibility

We studied the in vitro activity of fluconazole (FCZ), ketoconazole (KTZ), miconazole (MCZ), voriconazole (VCZ), itraconazole (ITZ) and amphotericin B (AMB) against the three major pathogenic Malassezia species, M. globosa, M. sympodialis, and M. furfur. Antifungal susceptibilities were determined using the broth microdilution method in accordance with Clinical and Laboratory Standards Institute reference document M27-A3. To support lipid-dependent yeast development, glucose, peptone, ox bile, malt extract, glycerol, and Tween supplements were added to Roswell Park Memorial Institute RPMI 1640 medium. The supplemented medium allowed good growth of all three species studied. The minimal inhibitory concentrations (MICs) were recorded after 72 h of incubation at 32ºC. The three species showed different susceptibility profiles for the drugs tested. Malassezia sympodialis was the most susceptible and M. furfur the least susceptible species. KTZ, ITZ, and VCZ were the most active drugs, showing low variability among isolates of the same species. FCZ, MCZ, and AMB showed high MICs and wide MIC ranges. Differences observed emphasize the need to accurately identify and evaluate antifungal susceptibility of Malassezia species. Further investigations and collaborative studies are essential for correlating in vitro results with clinical outcomes since the existing limited data do not allow definitive conclusions.

We studied 23 clinical and environmental strains of Sporothrix schenckii sensu lato collected from 1984 to 2017 in Argentina. The molecular identification (partial sequencing of a fragment of the calmodulin gene) of the strains was performed. For the yeast and mycelial phases, the in vitro susceptibility testing by a microdilution reference method was determined against eight antifungal drugs. Strains studied were identified as S. schenckii sensu stricto 13 (56.5%), S. brasiliensis 8 (34.7%) and S. globosa 2 (8.7%). The most active antifungal drugs tested for the yeast and mycelial phases expressed as geometric mean (GM) value of the minimal inhibitory concentration (MIC) (μg mL ) were terbinafine (0.07 and 0.24), posaconazole (0.13 and 0.58), itraconazole (0.38 and 1.10) and ketoconazole (0.22 and 0.89), while fluconazole (110.10 and 131.92) and flucytosine (2.96 and 79.03) were the less active. For voriconazole and amphotericin B the GM-MIC values were acceptably low for the yeast phase (0.39 and 0.72 μg mL ), while the mycelial phase showed values ≥2-fold higher (8.76 and 1.88 μg mL ), P < .05. Here, we described S. schenckii sensu stricto, S. brasiliensis and S. globosa, these species were isolated from humans, animals and soil and are circulating in Argentina since at least 1984.