RESUMEN
The region encompassing the Pacific Northwest (PNW), Vancouver Island, Oregon, and Washington has been the location of an ongoing Cryptococcus gattii outbreak since the 1990s, and there is evidence that the outbreak is expanding along the West Coast into California. Here we report a clinical case of a 69-year-old, HIV-negative man from North Carolina who was diagnosed with a fungal brain mass by magnetic resonance imaging (MRI) and pathology. He had traveled to Seattle and Vancouver 3 years earlier and to Costa Rica 4 months prior to presentation. Phenotypic evidence showed that the fungal mass isolated from the patient's brain represented C. gattii In agreement with the phenotypic results, multilocus sequence typing (MLST) provided genotypic evidence that assigned the infecting organism within the C. gattii species complex and to the C. deuterogattii VGIIa clade. Whole-genome sequencing revealed >99.99% identity with the C. deuterogattii reference strain R265, indicating that the infecting strain is derived from the highly clonal outbreak strains in the PNW. We conclude that the patient acquired the C. gattii infection during his travel to the region 3 years prior and that the infection was dormant for an extended period of time before causing disease. The patient tested positive for anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibodies, supporting earlier reports that implicate these autoantibodies as a risk factor associated with C. gattii infection.IMPORTANCE Mortality rates associated with C. gattii infections are estimated to be between 13% and 33%, depending on an individual's predisposition, and C. gattii has caused at least 39 deaths in the PNW region. There have been four other international travel cases reported in patients from Europe and Asia with travel history to the PNW, but this report describes the first North American traveler who acquired C. deuterogattii infection presenting within the United States and the first case of a C. deuterogattii outbreak infection associated with anti-GM-CSF autoantibodies. Early and accurate diagnoses are important for disease prevention and treatment and for control of infectious diseases. Continual reporting of C. deuterogattii infections is necessary to raise awareness of the ongoing outbreak in the PNW and to alert travelers and physicians to the areas of endemicity with potential risks.
Asunto(s)
Autoanticuerpos/sangre , Enfermedades Autoinmunes/complicaciones , Cryptococcus/aislamiento & purificación , Factor Estimulante de Colonias de Granulocitos y Macrófagos/antagonistas & inhibidores , Meningitis Criptocócica/diagnóstico , Meningitis Criptocócica/patología , Enfermedad Relacionada con los Viajes , Anciano , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Costa Rica , Cryptococcus/clasificación , Cryptococcus/genética , Genotipo , Humanos , Huésped Inmunocomprometido , Imagen por Resonancia Magnética , Masculino , Técnicas Microbiológicas , Tipificación de Secuencias Multilocus , North Carolina , Noroeste de Estados Unidos , Secuenciación Completa del GenomaRESUMEN
BACKGROUND: The class Tremellomycete (Agaricomycotina) encompasses more than 380 fungi. Although there are a few edible Tremella spp., the only species with current biotechnological use is the astaxanthin-producing yeast Phaffia rhodozyma (Cystofilobasidiales). Besides astaxanthin, a carotenoid pigment with potent antioxidant activity and great value for aquaculture and pharmaceutical industries, P. rhodozyma possesses multiple exceptional traits of fundamental and applied interest. The aim of this study was to obtain, and analyze two new genome sequences of representative strains from the northern (CBS 7918T, the type strain) and southern hemispheres (CRUB 1149) and compre them to a previously published genome sequence (strain CBS 6938). Photoprotection and antioxidant related genes, as well as genes involved in sexual reproduction were analyzed. RESULTS: Both genomes had ca. 19 Mb and 6000 protein coding genes, similar to CBS 6938. Compared to other fungal genomes P. rhodozyma strains and other Cystofilobasidiales have the highest number of intron-containing genes and highest number of introns per gene. The Patagonian strain showed 4.4 % of nucleotide sequence divergence compared to the European strains which differed from each other by only 0.073 %. All known genes related to the synthesis of astaxanthin were annotated. A hitherto unknown gene cluster potentially responsible for photoprotection (mycosporines) was found in the newly sequenced P. rhodozyma strains but was absent in the non-mycosporinogenic strain CBS 6938. A broad battery of enzymes that act as scavengers of free radical oxygen species were detected, including catalases and superoxide dismutases (SODs). Additionally, genes involved in sexual reproduction were found and annotated. CONCLUSIONS: A draft genome sequence of the type strain of P. rhodozyma is now available, and comparison with that of the Patagonian population suggests the latter deserves to be assigned to a distinct variety. An unexpected genetic trait regarding high occurrence of introns in P. rhodozyma and other Cystofilobasidiales was revealed. New genomic insights into fungal homothallism were also provided. The genetic basis of several additional photoprotective and antioxidant strategies were described, indicating that P. rhodozyma is one of the fungi most well-equipped to cope with environmental oxidative stress, a factor that has probably contributed to shaping its genome.
Asunto(s)
Basidiomycota/genética , Variación Genética , Genoma Fúngico , Genómica , Antioxidantes/metabolismo , Basidiomycota/metabolismo , Basidiomycota/efectos de la radiación , Catalasa/metabolismo , Biología Computacional/métodos , Orden Génico , Genómica/métodos , Secuenciación de Nucleótidos de Alto Rendimiento , Reproducción Asexuada/genética , Rayos UltravioletaRESUMEN
Species of Leucosporidiales are a group of psychrotolerant yeasts with biotechnological potential. In the present work, we studied the phenotypic, genetic and sexual characteristics of three species of this genus (Leucosporidium scottii, Leucosporidiella creatinivora and Le. yakutica) to clarify the evolutionary relationship among these closely related taxa. From the results obtained, it becomes clear that these yeasts can interbreed. Although genetic delimitation is possible for the three species, the extent of nucleotide substitutions and phenotypic differences observed between them are lower than that expected for species that have ended the speciation process. Our taxonomic conclusion is to maintain the three taxa until further genomic data are gathered. However, the concept of L. scottii species complex is proposed for this group of species. Finally, we transfer all Leucosporidiella and Mastigobasidium species to Leucosporidium (Leucosporidiales), and, in order to end the polyphyly condition of these taxa, we propose the new genus Pseudoleucosporidium gen. nov. and the new combination Peudoleucosporidium fasciculatum comb. nov.