Nathan P. Wiederhold

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Invasive aspergillosis (IA) is the most important opportunistic mycosis in immunosuppressed patients. The lack of a sufficient number of effective antifungals and our incomplete understanding of the pathogenesis of IA contribute to its overall unfavorable prognosis. Studies of drug efficacy against IA and Aspergillus virulence rely on conventional animal(More)
Invasive aspergillosis is an increasingly common and often fatal opportunistic fungal infection in patients with hematologic malignancies. Prolonged and profound neutropenia remains a key risk factor for the development of invasive aspergillosis. However, qualitative deficiencies in host immune responses resulting from prolonged corticosteroid therapy,(More)
Azole resistance in Aspergillus fumigatus is an increasing problem. The TR34 L98H and TR46 Y121F T289A mutations that can occur in patients without previous azole exposure have been reported in Europe, Asia, the Middle East, Africa, and Australia. Here, we report the detection of both the TR34 L98H and TR46 Y121F T289A mutations in confirmed A. fumigatus(More)
Novel species of fungi described in the present study include the following from Malaysia: Castanediella eucalypti from Eucalyptus pellita, Codinaea acacia from Acacia mangium, Emarcea eucalyptigena from Eucalyptus brassiana, Myrtapenidiella eucalyptorum from Eucalyptus pellita, Pilidiella eucalyptigena from Eucalyptus brassiana and Strelitziana malaysiana(More)
Gliotoxin was measured in the lungs (mean, 3,976 +/- 1,662 ng/g of tissue) and sera (mean, 36.5 +/- 30.28 ng/ml) of mice with experimentally induced invasive aspergillosis (IA), and levels decreased with antifungal therapy. Gliotoxin could also be detected in the sera of cancer patients with documented (proven or probable) IA.
We measured antifungal activity against 128 cryptococcal isolates (86 of C. neoformans and 42 of C. gattii) to determine if differences in serotype susceptibility exist. Contrary to previous results, we found no serotype susceptibility differences. Isavuconazole, posaconazole, and voriconazole demonstrated excellent potency against each isolate and(More)
The 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(More)
Caspofungin had diminished activity in vitro against Candida albicans at concentrations of 8 to 32 microg/ml. This phenomenon was markedly attenuated in a deltamkc1/deltamkc1 deletion mutant and by the addition of cyclosporine to the wild type. Short exposure to these caspofungin concentrations resulted in MKC1 up-regulation, suggesting roles of cell wall(More)
The fungal genus Pithomyces comprises numerous dematiaceous saprobic species commonly found on dead leaves and stems of a great variety of plants. Occasionally, they have been recovered from clinical specimens. We morphologically and molecularly (rDNA sequences) investigated a set of 42 isolates tentatively identified as Pithomyces recovered from clinical(More)
Multilocus DNA sequence data were used to assess the genetic diversity and evolutionary relationships of 67 Fusarium strains from veterinary sources, most of which were from the United States. Molecular phylogenetic analyses revealed that the strains comprised 23 phylogenetically distinct species, all but two of which were previously known to infect humans,(More)