A significant number of reported Absidia corymbifera (Lichtheimia corymbifera) infections are caused by Lictheimia ramosa (syn. Lichtheimia hongkongensis): an emerging cause of mucormycosis

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Subcutaneous Phaeohyphomycotic Nodule Due to Phialemoniopsis hongkongensis sp. nov.

Phialemoniopsis species are ubiquitous dematiaceous molds associated with a wide variety of superficial and systemic infections in human. In this study, we isolated a mold from the forearm nodule biopsy specimen from a patient with underlying liver cirrhosis, ankylosing spondylosis, and tuberculosis. He was treated with itraconazole, but unfortunately, he succumbed as a result of disseminated tuberculosis with multiorgan failure. The histology results of the skin biopsy showed necrotizing granulomas in which numerous fungal elements were found. On Sabouraud dextrose agar, the fungal isolate grew as white-to-cream and smooth-to-velvety colonies. Microscopically, oval-to-cylindrical conidia were observed from abundant adelophialides, which possessed barely visible parallel collarettes but no basal septa. The azole drugs voriconazole, itraconazole, and posaconazole, as well as amphotericin B, showed high activities against this fungus. Internal transcribed spacer, 28S nuclear ribosomal DNA (nrDNA), and β-actin and β-tubulin gene sequencing showed that this fungus is most closely related to but distinct from Phialemonium curvata. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and hierarchical cluster analysis showed that the MALDI-TOF MS spectrum of this fungus is most closely related to that of Phialemonium pluriloculosa. We propose a new species, Phialemoniopsis hongkongensis sp. nov., to describe this fungus

Biotyping of Penicillium marneffei reveals concentration- dependent growth inhibition by galactose

Thirty-two isolates of the dimorphic fungus Penicillium marneffei were studied for their biochemical properties. All isolates possessed the enzyme urease and were inhibited by 500 mg of cycloheximide per liter. No strain fermented glucose, and thus no strain fermented any of the other five sugars tested. All assimilated glucose, maltose, and cellobiose; only one of the isolates did not assimilate salicin. Totals of 65.6, 84.4, and 71.9% of the isolates assimilated trehalose, xylose, and nitrate, respectively. Twelve strains possessed the enzyme β-galactosidase. Overall, 17 different biotypes were recognized, but no association was found between the human immunodeficiency virus status of the patients and the biotype. A novel finding of concentrationdependent growth inhibition of P. marneffei by galactose is described. Inhibition of growth occurred at a low concentration of galactose (0.015 to 0.25%) when galactose was the sole carbon source in the medium. Morphological changes of the fungal cells were observed in the presence of galactose.published_or_final_versio

First report of Tsukamurella keratitis: Association between T. tyrosinosolvens and T. pulmonis and ophthalmologic infections

We describe the first two cases of Tsukamurella keratitis, presented as eye pain with or without blurring of vision. One case was associated with trichiasis and the other with contact lens wear. The two isolates were identified as T. tyrosinosolvens and T. pulmonis, respectively, by phenotypic characterization and 16S rRNA sequencing. Copyright © 2009, American Society for Microbiology. All Rights Reserved.link_to_OA_fulltex

High diversity of polyketide synthase genes and the melanin biosynthesis gene cluster in Penicillium marneffei

Despite the unique phenotypic properties and clinical importance of Penicillium marneffei, the polyketide synthase genes in its genome have never been characterized. Twenty-three putative polyketide synthase genes and two putative polyketide synthase nonribosomal peptide-synthase hybrid genes were identified in the P. marneffei genome, a diversity much higher than found in other pathogenic thermal dimorphic fungi, such as Histoplasma capsulatum (one polyketide synthase gene) and Coccidioides immitis (10 polyketide synthase genes). These genes were evenly distributed on the phylogenetic tree with polyketide synthase genes of Aspergillus and other fungi, indicating that the high diversity was not a result of lineage-specific gene expansion through recent gene duplication. The melanin-biosynthesis gene cluster had gene order and orientations identical to those in the Talaromyces stipitatus (a teleomorph of Penicillium emmonsii) genome. Phylogenetically, all six genes of the melanin-biosynthesis gene cluster in P. marneffei were also most closely related to those in T. stipitatus, with high bootstrap supports. The polyketide synthase gene of the melanin-biosynthesis gene cluster (alb1) in P. marneffei was knocked down, which was accompanied by loss of melanin pigment production and reduced ornamentation in conidia. The survival of mice challenged with the alb1 knockdown mutant was significantly better than those challenged with wild-type P. marneffei (P < 0.005). The sterilizing doses of hydrogen peroxide, leading to a 50% reduction in survival of conidia, were 11 min for wild-type P. marneffei and 6 min for the alb1 knockdown mutant of P. marneffei, implying that the melanin-biosynthesis gene cluster contributed to virulence through decreased susceptibility to killing by hydrogen peroxide. © 2010 FEBS.link_to_subscribed_fulltex

Lichtheimia hongkongensis sp. nov., a novel Lichtheimia spp. associated with rhinocerebral, gastrointestinal, and cutaneous mucormycosis

Three thermotolerant "Absidia-like" isolates with unique morphologic characteristics, recovered from nasopharyngeal swab of a liver transplant recipient, gastric biopsy of a renal transplant recipient, and skin biopsy of a man with burn, respectively, were characterized. Microscopic examination showed nonseptate hyphae with highly branched sporangiophores. Uniquely, most side branches were circinate, and abundant pleomorphic giant cells with fingerlike projections were observed, characteristics absent from other Absidia/. Lichtheimia spp. ITS1-5.8S-ITS2 rRNA gene cluster, partial EF1α gene, and partial β-actin gene sequencing showed that the 3 strains formed a distinct cluster, most closely related to, but distinct from, Lichtheimia corymbifera, Lichtheimia blakesleeana, and Lichtheimia hyalospora. Based on the morphologic and genotypic characteristics, we propose a new species, Lichtheimia hongkongensis sp. nov., to describe this fungus, which caused rhinocerebral, gastrointestinal, and cutaneous mucormycosis, respectively, in 3 patients. A significant proportion of L. corymbifera associated with mucormycosis reported may be L. hongkongensis. © 2010 Elsevier Inc.link_to_subscribed_fulltex

Heterogeneity of internal transcribed spacer region sequence in Rhizopus microsporus: implications for moelecular diagnosis

Session - Patients with CancerThis journal suppl. entitled: Special Issue: Abstracts of the 16th ICHS ... 2010BACKGROUND: In fungi, the 18S rDNA gene and internal transcribed spacer region (ITS) the most widely used targets for molecular identi¬fication. Although ITS sequence heterogeneity has been reported in a few fungal species, it has never been described in members of the order Mucorales, the etiological agents of the highly fatal mucormycosis. Recently, during the outbreak investigation of intestinal mucormycosis due to Rhizopus microsporus in patients with hematological malignan¬cies, 28 strains of R. microsporus were subjected to ITS sequencing. In four out of 28 strains, double peaks were frequently observed in …link_to_OA_fulltex