The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Jennifer K Meece - One of the best experts on this subject based on the ideXlab platform.
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persistent and nonprogressive cutaneous blastomycosis in a pregnant adolescent
JAAD case reports, 2020Co-Authors: Jennifer L Anderson, Matthew C Hall, Erik J Stratman, Jennifer K MeeceAbstract:Blastomycosis is a fungal infection endemic to the Great Lakes region and Mississippi River Valley,1 although it is found worldwide. Although asymptomatic infections have been recognized, blastomycosis is usually a respiratory syndrome with rare cases of fulminant respiratory failure from acute respiratory distress syndrome. Dissemination to skin, bone, and other organs without obvious lung disease is not uncommon.2 Six distinct species of Blastomyces have been described,3, 4 with 4 that are pathogenic to humans. Of these, Blastomyces dermatitidis is more likely to cause disseminated disease and Blastomyces gilchristii is more often associated with pulmonary-only disease.2 Blastomyces percursus and Blastomyces helicus are newly described human pathogens, and not much is known about how they present clinically. Gestational blastomycosis is rare and presents a risk for disseminated disease in the mother and fetus because of the relative immunosuppression of pregnancy.5, 6, 7 Systemic blastomycosis in pregnant patients may be fatal to the fetus, especially when left untreated.5 We describe an adolescent patient with untreated cutaneous blastomycosis that remained in situ through 2 pregnancies.
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Molecular detection of Blastomyces in an air sample from an outbreak associated residence.
Medical mycology, 2018Co-Authors: Jennifer L Anderson, Jennifer K MeeceAbstract:Based on epidemiologic data during a blastomycosis outbreak, exposure within the home was suspected for two case patients that resided together. Soil and air samples were collected from the basement of their residence. Samples were tested for Blastomyces by culture and polymerase chain reaction (PCR) to compare with an available clinical isolate. An air sample from the basement of the residence was PCR positive for Blastomyces. Sequence data from the air sample and the outbreak clinical isolate were identified as different Blastomyces spp. Despite this, our findings suggest that the basement was suitable for the growth of Blastomyces and airborne organism was circulating.
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development and validation of a novel single nucleotide polymorphism snp panel for genetic analysis of Blastomyces spp and association analysis
BMC Infectious Diseases, 2016Co-Authors: Holly M Frost, Jennifer L Anderson, John M. Embil, Lynn Ivacic, Brian L Sloss, Jennifer K MeeceAbstract:Single nucleotide polymorphism (SNP) genotyping is increasingly being utilized for molecular typing of pathogens and is cost-effective, especially for large numbers of isolates. The goals of this study were 1) to develop and validate a SNP assay panel for genetic analysis of Blastomyces spp., 2) ascertain whether microsatellite genotyping and the SNP genotyping with the developed panel resolve identical genetic groups, and 3) explore the utility of SNPs for examining phylogenetic and virulence questions in humans. Three hundred sixty unique Blastomyces spp. isolates previously genotyped with microsatellite markers were genotyped with the MassARRAY® SNP genotyping system (Agena Bioscience™, San Diego, CA), for a custom panel of 28 SNPs. Clinical presentation data was analyzed for association with SNP variants. Three hundred twenty-three Blastomyces spp. isolates (90 %) were successfully genotyped by SNP analysis, with results obtained for at least 27 of 28 assays. For 99.7 % of isolates tested by both genotyping methods, microsatellite genetic group assignment correlated with species assignment based on internal transcribed spacer 2 (ITS2) genotyping, with Group 1 (Gr 1) being equivalent to B. gilchristii and Group 2 (Gr 2) being equivalent to B. dermatitidis. Thirteen isolates were genetic hybrids by one or both methods of genotyping and were difficult to assign to a particular genetic group or species. Fifteen SNP loci showed significantly different alleles in cases of pulmonary vs disseminated disease, at a p-value of <0.01 or less. This study is the largest genotyping study of Blastomyces spp. isolates and presents a new method for genetic analysis with which to further explore the relationship between the genetic diversity in Blastomyces spp. and clinical disease presentation. We demonstrated that microsatellite Gr 1 is equivalent to B. gilchristii and Gr 2 is equivalent to B. dermatitidis. We also discovered potential evidence of infrequent recombination between the two Blastomyces spp. Several Blastomyces spp. SNPs were identified as associated with dissemination or pulmonary disease presentation, but additional work is needed to examine virulence SNPs separately within B. dermatitidis and B. gilchristii.
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Development and validation of a novel single nucleotide polymorphism (SNP) panel for genetic analysis of Blastomyces spp. and association analysis
BMC Infectious Diseases, 2016Co-Authors: Holly M Frost, Jennifer L Anderson, Lynn Ivacic, Brian L Sloss, John Embil, Jennifer K MeeceAbstract:Background Single nucleotide polymorphism (SNP) genotyping is increasingly being utilized for molecular typing of pathogens and is cost-effective, especially for large numbers of isolates. The goals of this study were 1) to develop and validate a SNP assay panel for genetic analysis of Blastomyces spp. , 2) ascertain whether microsatellite genotyping and the SNP genotyping with the developed panel resolve identical genetic groups, and 3) explore the utility of SNPs for examining phylogenetic and virulence questions in humans. Methods Three hundred sixty unique Blastomyces spp. isolates previously genotyped with microsatellite markers were genotyped with the MassARRAY® SNP genotyping system (Agena Bioscience™, San Diego, CA), for a custom panel of 28 SNPs. Clinical presentation data was analyzed for association with SNP variants. Results Three hundred twenty-three Blastomyces spp. isolates (90 %) were successfully genotyped by SNP analysis, with results obtained for at least 27 of 28 assays. For 99.7 % of isolates tested by both genotyping methods, microsatellite genetic group assignment correlated with species assignment based on internal transcribed spacer 2 (ITS2) genotyping, with Group 1 (Gr 1) being equivalent to B. gilchristii and Group 2 (Gr 2) being equivalent to B. dermatitidis . Thirteen isolates were genetic hybrids by one or both methods of genotyping and were difficult to assign to a particular genetic group or species. Fifteen SNP loci showed significantly different alleles in cases of pulmonary vs disseminated disease, at a p -value of
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Development and validation of a novel single nucleotide polymorphism (SNP) panel for genetic analysis of Blastomyces spp. and association analysis.
BMC infectious diseases, 2016Co-Authors: Holly M Frost, Jennifer L Anderson, John M. Embil, Lynn Ivacic, Brian L Sloss, Jennifer K MeeceAbstract:Single nucleotide polymorphism (SNP) genotyping is increasingly being utilized for molecular typing of pathogens and is cost-effective, especially for large numbers of isolates. The goals of this study were 1) to develop and validate a SNP assay panel for genetic analysis of Blastomyces spp., 2) ascertain whether microsatellite genotyping and the SNP genotyping with the developed panel resolve identical genetic groups, and 3) explore the utility of SNPs for examining phylogenetic and virulence questions in humans. Three hundred sixty unique Blastomyces spp. isolates previously genotyped with microsatellite markers were genotyped with the MassARRAY® SNP genotyping system (Agena Bioscience™, San Diego, CA), for a custom panel of 28 SNPs. Clinical presentation data was analyzed for association with SNP variants. Three hundred twenty-three Blastomyces spp. isolates (90 %) were successfully genotyped by SNP analysis, with results obtained for at least 27 of 28 assays. For 99.7 % of isolates tested by both genotyping methods, microsatellite genetic group assignment correlated with species assignment based on internal transcribed spacer 2 (ITS2) genotyping, with Group 1 (Gr 1) being equivalent to B. gilchristii and Group 2 (Gr 2) being equivalent to B. dermatitidis. Thirteen isolates were genetic hybrids by one or both methods of genotyping and were difficult to assign to a particular genetic group or species. Fifteen SNP loci showed significantly different alleles in cases of pulmonary vs disseminated disease, at a p-value of
Lynne Sigler - One of the best experts on this subject based on the ideXlab platform.
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Blastomyces helicus a new dimorphic fungus causing fatal pulmonary and systemic disease in humans and animals in western canada and the united states
Clinical Infectious Diseases, 2019Co-Authors: Ilan S. Schwartz, Nathan P. Wiederhold, Kimberly E Hanson, Thomas F Patterson, Lynne SiglerAbstract:Background Blastomyces helicus (formerly Emmonsia helica) is a dimorphic fungus first isolated from a man with fungal encephalitis in Alberta, Canada. The geographic range, epidemiology, and clinical features of disease are unknown. Methods We reviewed human and veterinary isolates of B. helicus identified among Blastomyces and Emmonsia isolates at the University of Alberta Microfungus Collection and Herbarium, University of Texas Health San Antonio's Fungus Testing Laboratory, and Associated Regional and University Pathologists Laboratories. Isolates were selected based on low Blastomyces dermatitidis DNA probe values and/or atypical morphology. Species identification was confirmed for most isolates by DNA sequence analysis of the internal transcribed spacer with or without D1/D2 ribosomal RNA regions. Epidemiological and clinical data were analyzed. Results We identified isolates from 10 human and 5 veterinary cases of B. helicus infection; all were referred from western regions of Canada and the United States. Isolates remained sterile in culture, producing neither conidia nor sexual spores in the mycelial phase, but often producing coiled hyphae. Isolates were most frequently cultured from blood and bronchoalveolar lavage in humans and lungs in animals. Most infected persons were immunocompromised. Histopathological findings included pleomorphic, small or variably sized yeast-like cells, with single or multiple budding, sometimes proliferating to form short, branching, hyphal-like elements. Disease carried a high case-fatality rate. Conclusions Blastomyces helicus causes fatal pulmonary and systemic disease in humans and companion animals. It differs from B. dermatitidis in morphological presentation in culture and in histopathology, by primarily affecting immunocompromised persons, and in a geographic range that includes western regions of North America.
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Phylogeny, ecology and taxonomy of systemic pathogens and their relatives in Ajellomycetaceae (Onygenales): Blastomyces , Emergomyces , Emmonsia , Emmonsiellopsis
Fungal Diversity, 2018Co-Authors: Yanping Jiang, Lynne Sigler, Karolina Dukik, José F. Muñoz, Peiying Feng, Bert Gerrits Van Den Ende, Ilan S. Schwartz, Nelesh P. Govender, Chris Kenyon, J. Benjamin StielowAbstract:The family Ajellomycetaceae (Onygenales) includes mammal-associated pathogens within the genera Blastomyces, Emmonsia, Histoplasma and Paracoccidioides, as well as the recently described genera, Emergomyces that causes disease in immunocompromised hosts, and Emmonsiellopsis, known only from soil. To further assess the phylogenetic relationships among and between members of these genera and several previously undescribed species, we sequenced and analyzed the DNA-directed RNA polymerase II (rPB2), translation elongation factor 3-α (TEF3), β-tubulin (TUB2), 28S large subunit rDNA (LSU) and the internal transcribed spacer regions (ITS) in 68 strains, in addition to morphological and physiological investigations. To better understand the thermal dimorphism among these fungi, the dynamic process of transformation from mycelial to yeast-like or adiaspore-like forms was also assessed over a range of temperatures (6–42 °C). Molecular data resolved the relationships and recognized five major well-supported lineages that correspond largely to the genus level. Emmonsia, typified by Emmonsia parva, is a synonym of Blastomyces that also accommodates Blastomyces helicus (formerly Emmonsia helica). Emmonsia crescens is phylogenetically distinct, and found closely related to a single strain from soil without known etiology. Blastomyces silverae, Emergomyces canadensis, Emergomyces europaeus and Emmonsia sola are newly described. Almost all of the taxa are associated with human and animal disease. Emmonsia crescens, B. dermatitidis and B. parvus are prevalently associated with pulmonary disease in humans or animals. Blastomyces helicus, B. percursus, Emergomyces africanus, Es. canadensis, Es. europaeus, Es. orientalis and Es. pasteurianus (formerly Emmonsia pasteuriana) are predominantly found in human hosts with immune disorders; no animal hosts are known for these species except B. helicus.
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Blastomyces helicus an emerging dimorphic fungal pathogen causing fatal pulmonary and disseminated disease in humans and animals in western canada and united states
Open Forum Infectious Diseases, 2017Co-Authors: Ilan S. Schwartz, Nathan P. Wiederhold, Thomas F Patterson, Lynne SiglerAbstract:Background Blastomyces helicus (formerly Emmonsia helica) is a recently described dimorphic fungus first isolated from a man who died of encephalitis in Alberta, Canada. The geographic range, epidemiology and clinical features are unknown.
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Novel taxa of thermally dimorphic systemic pathogens in the Ajellomycetaceae (Onygenales).
Mycoses, 2017Co-Authors: Karolina Dukik, Lynne Sigler, Yanping Jiang, José F. Muñoz, Peiying Feng, J. Benjamin Stielow, Joanna Freeke, Azadeh Jamalian, Bert Gerrits Van Den Ende, Juan G. McewenAbstract:Recent discoveries of novel systemic fungal pathogens with thermally dimorphic yeast-like phases have challenged the current taxonomy of the Ajellomycetaceae, a family currently comprising the genera Blastomyces, Emmonsia, Emmonsiellopsis, Helicocarpus, Histoplasma, Lacazia and Paracoccidioides. Our morphological, phylogenetic and phylogenomic analyses demonstrated species relationships and their specific phenotypes, clarified generic boundaries and provided the first annotated genome assemblies to support the description of two new species. A new genus, Emergomyces, accommodates Emmonsia pasteuriana as type species, and the new species Emergomyces africanus, the aetiological agent of case series of disseminated infections in South Africa. Both species produce small yeast cells that bud at a narrow base at 37°C and lack adiaspores, classically associated with the genus Emmonsia. Another novel dimorphic pathogen, producing broad-based budding cells at 37°C and occurring outside North America, proved to belong to the genus Blastomyces, and is described as Blastomyces percursus.
José F. Muñoz - One of the best experts on this subject based on the ideXlab platform.
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Human Blastomycosis in South Africa Caused by Blastomyces percursus and Blastomyces emzantsi sp. nov., 1967 to 2014.
Journal of clinical microbiology, 2020Co-Authors: Tsidiso G. Maphanga, José F. Muñoz, Ilan S. Schwartz, Monica Birkhead, Mushal Allam, Thokozile G. Zulu, Christina A. Cuomo, Arshad Ismail, Serisha D. Naicker, Ruth S. MpembeAbstract:ABSTRACT We reevaluated 20 cases of blastomycosis diagnosed in South Africa between 1967 and 2014, with Blastomyces dermatitidis considered to be the etiological agent, in light of newly described species and the use of more advanced technologies. In addition to histopathological and/or culture-based methods, all 20 isolates were phenotypically and genotypically characterized, including multilocus typing of five genes and whole-genome sequencing. Antifungal susceptibility testing was performed as outlined by Clinical and Laboratory Standards Institute documents M27-A3 and M38-A2. We merged laboratory and corresponding clinical case data, where available. Morphological characteristics and phylogenetic analyses of five-gene and whole-genome sequences revealed two groups, both of which were closely related to but distinct from B. dermatitidis, Blastomyces gilchristii, and Blastomyces parvus. The first group (n = 12) corresponded to the recently described species Blastomyces percursus, and the other (n = 8) is described here as Blastomyces emzantsi sp. nov. Both species exhibited incomplete conversion to the yeast phase at 37°C and were heterothallic for mating types. All eight B. emzantsi isolates belonged to the α mating type. Whole-genome sequencing confirmed distinct species identities as well as the absence of a full orthologue of the BAD-1 gene. Extrapulmonary (skin or bone) disease, probably resulting from hematogenous spread from a primary lung infection, was more common than pulmonary disease alone. Voriconazole, posaconazole, itraconazole, amphotericin B, and micafungin had the most potent in vitro activity. Over the 5 decades, South African cases of blastomycosis were caused by species that are distinct from B. dermatitidis. Increasing clinical awareness and access to simple rapid diagnostics may improve the diagnosis of blastomycosis in resource-limited countries.
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Phylogeny, ecology and taxonomy of systemic pathogens and their relatives in Ajellomycetaceae (Onygenales): Blastomyces , Emergomyces , Emmonsia , Emmonsiellopsis
Fungal Diversity, 2018Co-Authors: Yanping Jiang, Lynne Sigler, Karolina Dukik, José F. Muñoz, Peiying Feng, Bert Gerrits Van Den Ende, Ilan S. Schwartz, Nelesh P. Govender, Chris Kenyon, J. Benjamin StielowAbstract:The family Ajellomycetaceae (Onygenales) includes mammal-associated pathogens within the genera Blastomyces, Emmonsia, Histoplasma and Paracoccidioides, as well as the recently described genera, Emergomyces that causes disease in immunocompromised hosts, and Emmonsiellopsis, known only from soil. To further assess the phylogenetic relationships among and between members of these genera and several previously undescribed species, we sequenced and analyzed the DNA-directed RNA polymerase II (rPB2), translation elongation factor 3-α (TEF3), β-tubulin (TUB2), 28S large subunit rDNA (LSU) and the internal transcribed spacer regions (ITS) in 68 strains, in addition to morphological and physiological investigations. To better understand the thermal dimorphism among these fungi, the dynamic process of transformation from mycelial to yeast-like or adiaspore-like forms was also assessed over a range of temperatures (6–42 °C). Molecular data resolved the relationships and recognized five major well-supported lineages that correspond largely to the genus level. Emmonsia, typified by Emmonsia parva, is a synonym of Blastomyces that also accommodates Blastomyces helicus (formerly Emmonsia helica). Emmonsia crescens is phylogenetically distinct, and found closely related to a single strain from soil without known etiology. Blastomyces silverae, Emergomyces canadensis, Emergomyces europaeus and Emmonsia sola are newly described. Almost all of the taxa are associated with human and animal disease. Emmonsia crescens, B. dermatitidis and B. parvus are prevalently associated with pulmonary disease in humans or animals. Blastomyces helicus, B. percursus, Emergomyces africanus, Es. canadensis, Es. europaeus, Es. orientalis and Es. pasteurianus (formerly Emmonsia pasteuriana) are predominantly found in human hosts with immune disorders; no animal hosts are known for these species except B. helicus.
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Novel taxa of thermally dimorphic systemic pathogens in the Ajellomycetaceae (Onygenales).
Mycoses, 2017Co-Authors: Karolina Dukik, Lynne Sigler, Yanping Jiang, José F. Muñoz, Peiying Feng, J. Benjamin Stielow, Joanna Freeke, Azadeh Jamalian, Bert Gerrits Van Den Ende, Juan G. McewenAbstract:Recent discoveries of novel systemic fungal pathogens with thermally dimorphic yeast-like phases have challenged the current taxonomy of the Ajellomycetaceae, a family currently comprising the genera Blastomyces, Emmonsia, Emmonsiellopsis, Helicocarpus, Histoplasma, Lacazia and Paracoccidioides. Our morphological, phylogenetic and phylogenomic analyses demonstrated species relationships and their specific phenotypes, clarified generic boundaries and provided the first annotated genome assemblies to support the description of two new species. A new genus, Emergomyces, accommodates Emmonsia pasteuriana as type species, and the new species Emergomyces africanus, the aetiological agent of case series of disseminated infections in South Africa. Both species produce small yeast cells that bud at a narrow base at 37°C and lack adiaspores, classically associated with the genus Emmonsia. Another novel dimorphic pathogen, producing broad-based budding cells at 37°C and occurring outside North America, proved to belong to the genus Blastomyces, and is described as Blastomyces percursus.
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the dynamic genome and transcriptome of the human fungal pathogen Blastomyces and close relative emmonsia
PLOS Genetics, 2015Co-Authors: José F. Muñoz, Thomas D Sullivan, Gregory M. Gauthier, Christopher A Desjardins, Juan E Gallo, Jason W Holder, Amber J Marty, John C Carmen, Zehua Chen, Li DingAbstract:Three closely related thermally dimorphic pathogens are causal agents of major fungal diseases affecting humans in the Americas: blastomycosis, histoplasmosis and paracoccidioidomycosis. Here we report the genome sequence and analysis of four strains of the etiological agent of blastomycosis, Blastomyces, and two species of the related genus Emmonsia, typically pathogens of small mammals. Compared to related species, Blastomyces genomes are highly expanded, with long, often sharply demarcated tracts of low GC-content sequence. These GC-poor isochore-like regions are enriched for gypsy elements, are variable in total size between isolates, and are least expanded in the avirulent B. dermatitidis strain ER-3 as compared with the virulent B. gilchristii strain SLH14081. The lack of similar regions in related species suggests these isochore-like regions originated recently in the ancestor of the Blastomyces lineage. While gene content is highly conserved between Blastomyces and related fungi, we identified changes in copy number of genes potentially involved in host interaction, including proteases and characterized antigens. In addition, we studied gene expression changes of B. dermatitidis during the interaction of the infectious yeast form with macrophages and in a mouse model. Both experiments highlight a strong antioxidant defense response in Blastomyces, and upregulation of dioxygenases in vivo suggests that dioxide produced by antioxidants may be further utilized for amino acid metabolism. We identify a number of functional categories upregulated exclusively in vivo, such as secreted proteins, zinc acquisition proteins, and cysteine and tryptophan metabolism, which may include critical virulence factors missed before in in vitro studies. Across the dimorphic fungi, loss of certain zinc acquisition genes and differences in amino acid metabolism suggest unique adaptations of Blastomyces to its host environment. These results reveal the dynamics of genome evolution and of factors contributing to virulence in Blastomyces.
Ilan S. Schwartz - One of the best experts on this subject based on the ideXlab platform.
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Human Blastomycosis in South Africa Caused by Blastomyces percursus and Blastomyces emzantsi sp. nov., 1967 to 2014.
Journal of clinical microbiology, 2020Co-Authors: Tsidiso G. Maphanga, José F. Muñoz, Ilan S. Schwartz, Monica Birkhead, Mushal Allam, Thokozile G. Zulu, Christina A. Cuomo, Arshad Ismail, Serisha D. Naicker, Ruth S. MpembeAbstract:ABSTRACT We reevaluated 20 cases of blastomycosis diagnosed in South Africa between 1967 and 2014, with Blastomyces dermatitidis considered to be the etiological agent, in light of newly described species and the use of more advanced technologies. In addition to histopathological and/or culture-based methods, all 20 isolates were phenotypically and genotypically characterized, including multilocus typing of five genes and whole-genome sequencing. Antifungal susceptibility testing was performed as outlined by Clinical and Laboratory Standards Institute documents M27-A3 and M38-A2. We merged laboratory and corresponding clinical case data, where available. Morphological characteristics and phylogenetic analyses of five-gene and whole-genome sequences revealed two groups, both of which were closely related to but distinct from B. dermatitidis, Blastomyces gilchristii, and Blastomyces parvus. The first group (n = 12) corresponded to the recently described species Blastomyces percursus, and the other (n = 8) is described here as Blastomyces emzantsi sp. nov. Both species exhibited incomplete conversion to the yeast phase at 37°C and were heterothallic for mating types. All eight B. emzantsi isolates belonged to the α mating type. Whole-genome sequencing confirmed distinct species identities as well as the absence of a full orthologue of the BAD-1 gene. Extrapulmonary (skin or bone) disease, probably resulting from hematogenous spread from a primary lung infection, was more common than pulmonary disease alone. Voriconazole, posaconazole, itraconazole, amphotericin B, and micafungin had the most potent in vitro activity. Over the 5 decades, South African cases of blastomycosis were caused by species that are distinct from B. dermatitidis. Increasing clinical awareness and access to simple rapid diagnostics may improve the diagnosis of blastomycosis in resource-limited countries.
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Blastomyces helicus a new dimorphic fungus causing fatal pulmonary and systemic disease in humans and animals in western canada and the united states
Clinical Infectious Diseases, 2019Co-Authors: Ilan S. Schwartz, Nathan P. Wiederhold, Kimberly E Hanson, Thomas F Patterson, Lynne SiglerAbstract:Background Blastomyces helicus (formerly Emmonsia helica) is a dimorphic fungus first isolated from a man with fungal encephalitis in Alberta, Canada. The geographic range, epidemiology, and clinical features of disease are unknown. Methods We reviewed human and veterinary isolates of B. helicus identified among Blastomyces and Emmonsia isolates at the University of Alberta Microfungus Collection and Herbarium, University of Texas Health San Antonio's Fungus Testing Laboratory, and Associated Regional and University Pathologists Laboratories. Isolates were selected based on low Blastomyces dermatitidis DNA probe values and/or atypical morphology. Species identification was confirmed for most isolates by DNA sequence analysis of the internal transcribed spacer with or without D1/D2 ribosomal RNA regions. Epidemiological and clinical data were analyzed. Results We identified isolates from 10 human and 5 veterinary cases of B. helicus infection; all were referred from western regions of Canada and the United States. Isolates remained sterile in culture, producing neither conidia nor sexual spores in the mycelial phase, but often producing coiled hyphae. Isolates were most frequently cultured from blood and bronchoalveolar lavage in humans and lungs in animals. Most infected persons were immunocompromised. Histopathological findings included pleomorphic, small or variably sized yeast-like cells, with single or multiple budding, sometimes proliferating to form short, branching, hyphal-like elements. Disease carried a high case-fatality rate. Conclusions Blastomyces helicus causes fatal pulmonary and systemic disease in humans and companion animals. It differs from B. dermatitidis in morphological presentation in culture and in histopathology, by primarily affecting immunocompromised persons, and in a geographic range that includes western regions of North America.
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Phylogeny, ecology and taxonomy of systemic pathogens and their relatives in Ajellomycetaceae (Onygenales): Blastomyces , Emergomyces , Emmonsia , Emmonsiellopsis
Fungal Diversity, 2018Co-Authors: Yanping Jiang, Lynne Sigler, Karolina Dukik, José F. Muñoz, Peiying Feng, Bert Gerrits Van Den Ende, Ilan S. Schwartz, Nelesh P. Govender, Chris Kenyon, J. Benjamin StielowAbstract:The family Ajellomycetaceae (Onygenales) includes mammal-associated pathogens within the genera Blastomyces, Emmonsia, Histoplasma and Paracoccidioides, as well as the recently described genera, Emergomyces that causes disease in immunocompromised hosts, and Emmonsiellopsis, known only from soil. To further assess the phylogenetic relationships among and between members of these genera and several previously undescribed species, we sequenced and analyzed the DNA-directed RNA polymerase II (rPB2), translation elongation factor 3-α (TEF3), β-tubulin (TUB2), 28S large subunit rDNA (LSU) and the internal transcribed spacer regions (ITS) in 68 strains, in addition to morphological and physiological investigations. To better understand the thermal dimorphism among these fungi, the dynamic process of transformation from mycelial to yeast-like or adiaspore-like forms was also assessed over a range of temperatures (6–42 °C). Molecular data resolved the relationships and recognized five major well-supported lineages that correspond largely to the genus level. Emmonsia, typified by Emmonsia parva, is a synonym of Blastomyces that also accommodates Blastomyces helicus (formerly Emmonsia helica). Emmonsia crescens is phylogenetically distinct, and found closely related to a single strain from soil without known etiology. Blastomyces silverae, Emergomyces canadensis, Emergomyces europaeus and Emmonsia sola are newly described. Almost all of the taxa are associated with human and animal disease. Emmonsia crescens, B. dermatitidis and B. parvus are prevalently associated with pulmonary disease in humans or animals. Blastomyces helicus, B. percursus, Emergomyces africanus, Es. canadensis, Es. europaeus, Es. orientalis and Es. pasteurianus (formerly Emmonsia pasteuriana) are predominantly found in human hosts with immune disorders; no animal hosts are known for these species except B. helicus.
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Blastomyces helicus an emerging dimorphic fungal pathogen causing fatal pulmonary and disseminated disease in humans and animals in western canada and united states
Open Forum Infectious Diseases, 2017Co-Authors: Ilan S. Schwartz, Nathan P. Wiederhold, Thomas F Patterson, Lynne SiglerAbstract:Background Blastomyces helicus (formerly Emmonsia helica) is a recently described dimorphic fungus first isolated from a man who died of encephalitis in Alberta, Canada. The geographic range, epidemiology and clinical features are unknown.
Bruce S Klein - One of the best experts on this subject based on the ideXlab platform.
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Turning on virulence: Mechanisms that underpin the morphologic transition and pathogenicity of Blastomyces.
Virulence, 2018Co-Authors: Joseph A Mcbride, Gregory M. Gauthier, Bruce S KleinAbstract:This review article focuses on the mechanisms underlying temperature adaptation and virulence of the etiologic agents of blastomycosis, Blastomyces dermatitidis, Blastomyces gilchristii, and Blastomyces percursus. In response to temperature, Blastomyces undergoes a reversible morphologic switch between hyphae and yeast known as the phase transition. The conversion to yeast for Blastomyces and related thermally dimorphic fungi is essential for virulence. In the yeast phase, Blastomyces upregulates the essential virulence factor, BAD1, which promotes attachment to host cells, impairs activation of immune cells, and blunts cytokine release. Blastomyces yeast also secrete dipeptidyl-peptidase IVA (DPPIVA), a serine protease that blunts the action of cytokines released from host immune cells. In vivo transcriptional profiling of Blastomyces yeast has uncovered genes such as PRA1 and ZRT1 involved in zinc scavenging that contribute to virulence during murine pulmonary infection. The discovery and characterization of genes important for virulence has led to advances at the bedside regarding novel diagnostics, vaccine development, and new targets for drug discovery.
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crispr cas9 mediated gene disruption reveals the importance of zinc metabolism for fitness of the dimorphic fungal pathogen Blastomyces dermatitidis
Mbio, 2018Co-Authors: Gregory C Kujoth, Thomas D Sullivan, Richard M Merkhofer, Taekjin Lee, Huafeng Wang, Tristan T Brandhorst, Marcel Wuthrich, Bruce S KleinAbstract:Blastomyces dermatitidis is a human fungal pathogen of the lung that can lead to disseminated disease in healthy and immunocompromised individuals. Genetic analysis of this fungus is hampered by the relative inefficiency of traditional recombination-based gene-targeting approaches. Here, we demonstrate the feasibility of applying CRISPR/Cas9-mediated gene editing to Blastomyces, including to simultaneously target multiple genes. We created targeting plasmid vectors expressing Cas9 and either one or two single guide RNAs and introduced these plasmids into Blastomyces via Agrobacterium gene transfer. We succeeded in disrupting several fungal genes, including PRA1 and ZRT1, which are involved in scavenging and uptake of zinc from the extracellular environment. Single-gene-targeting efficiencies varied by locus (median, 60% across four loci) but were approximately 100-fold greater than traditional methods of Blastomyces gene disruption. Simultaneous dual-gene targeting proceeded with efficiencies similar to those of single-gene-targeting frequencies for the respective targets. CRISPR/Cas9 disruption of PRA1 or ZRT1 had a variable impact on growth under zinc-limiting conditions, showing reduced growth at early time points in low-passage-number cultures and growth similar to wild-type levels by later passage. Individual impairment of PRA1 or ZRT1 resulted in a reduction of the fungal burden in a mouse model of Blastomyces infection by a factor of ~1 log (range, up to 3 logs), and combined disruption of both genes had no additional impact on the fungal burden. These results underscore the utility of CRISPR/Cas9 for efficient gene disruption in dimorphic fungi and reveal a role for zinc metabolism in Blastomyces fitness in vivoIMPORTANCEBlastomyces is a human fungal pathogen that can cause serious, even fatal, lung infections. Genetic analysis of this fungus is possible but inefficient. We applied a recently developed gene editing technology, CRISPR/Cas9, to dramatically improve the efficiency with which gene disruptions are introduced into Blastomyces We used this system to disrupt genes involved in zinc uptake and found that this reduced the fitness of the fungus upon infection.
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CRISPR/Cas9-Mediated Gene Disruption Reveals the Importance of Zinc Metabolism for Fitness of the Dimorphic Fungal Pathogen Blastomyces dermatitidis.
mBio, 2018Co-Authors: Gregory C Kujoth, Thomas D Sullivan, Richard M Merkhofer, Taekjin Lee, Huafeng Wang, Tristan T Brandhorst, Marcel Wuthrich, Bruce S KleinAbstract:Blastomyces dermatitidis is a human fungal pathogen of the lung that can lead to disseminated disease in healthy and immunocompromised individuals. Genetic analysis of this fungus is hampered by the relative inefficiency of traditional recombination-based gene-targeting approaches. Here, we demonstrate the feasibility of applying CRISPR/Cas9-mediated gene editing to Blastomyces, including to simultaneously target multiple genes. We created targeting plasmid vectors expressing Cas9 and either one or two single guide RNAs and introduced these plasmids into Blastomyces via Agrobacterium gene transfer. We succeeded in disrupting several fungal genes, including PRA1 and ZRT1, which are involved in scavenging and uptake of zinc from the extracellular environment. Single-gene-targeting efficiencies varied by locus (median, 60% across four loci) but were approximately 100-fold greater than traditional methods of Blastomyces gene disruption. Simultaneous dual-gene targeting proceeded with efficiencies similar to those of single-gene-targeting frequencies for the respective targets. CRISPR/Cas9 disruption of PRA1 or ZRT1 had a variable impact on growth under zinc-limiting conditions, showing reduced growth at early time points in low-passage-number cultures and growth similar to wild-type levels by later passage. Individual impairment of PRA1 or ZRT1 resulted in a reduction of the fungal burden in a mouse model of Blastomyces infection by a factor of ~1 log (range, up to 3 logs), and combined disruption of both genes had no additional impact on the fungal burden. These results underscore the utility of CRISPR/Cas9 for efficient gene disruption in dimorphic fungi and reveal a role for zinc metabolism in Blastomyces fitness in vivoIMPORTANCEBlastomyces is a human fungal pathogen that can cause serious, even fatal, lung infections. Genetic analysis of this fungus is possible but inefficient. We applied a recently developed gene editing technology, CRISPR/Cas9, to dramatically improve the efficiency with which gene disruptions are introduced into Blastomyces We used this system to disrupt genes involved in zinc uptake and found that this reduced the fitness of the fungus upon infection.
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CRISPR/Cas9-Mediated Gene Disruption Reveals the Importance of Zinc Metabolism for Fitness of the Dimorphic Fungal Pathogen Blastomyces dermatitidis
American Society for Microbiology, 2018Co-Authors: Gregory C Kujoth, Thomas D Sullivan, Richard M Merkhofer, Taekjin Lee, Huafeng Wang, Marcel Wuthrich, Bruce S Klein, Tristan Brandhorst, Joseph HeitmanAbstract:Blastomyces dermatitidis is a human fungal pathogen of the lung that can lead to disseminated disease in healthy and immunocompromised individuals. Genetic analysis of this fungus is hampered by the relative inefficiency of traditional recombination-based gene-targeting approaches. Here, we demonstrate the feasibility of applying CRISPR/Cas9-mediated gene editing to Blastomyces, including to simultaneously target multiple genes. We created targeting plasmid vectors expressing Cas9 and either one or two single guide RNAs and introduced these plasmids into Blastomyces via Agrobacterium gene transfer. We succeeded in disrupting several fungal genes, including PRA1 and ZRT1, which are involved in scavenging and uptake of zinc from the extracellular environment. Single-gene-targeting efficiencies varied by locus (median, 60% across four loci) but were approximately 100-fold greater than traditional methods of Blastomyces gene disruption. Simultaneous dual-gene targeting proceeded with efficiencies similar to those of single-gene-targeting frequencies for the respective targets. CRISPR/Cas9 disruption of PRA1 or ZRT1 had a variable impact on growth under zinc-limiting conditions, showing reduced growth at early time points in low-passage-number cultures and growth similar to wild-type levels by later passage. Individual impairment of PRA1 or ZRT1 resulted in a reduction of the fungal burden in a mouse model of Blastomyces infection by a factor of ~1 log (range, up to 3 logs), and combined disruption of both genes had no additional impact on the fungal burden. These results underscore the utility of CRISPR/Cas9 for efficient gene disruption in dimorphic fungi and reveal a role for zinc metabolism in Blastomyces fitness in vivo
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Neutrophils with DC characteristics (PMN-DCs) emerge during pulmonary blastomycosis.
2018Co-Authors: Scott J. Fites, Michael Gui, John F. Kernien, Paige Negoro, Zeina Dagher, David B. Sykes, Jeniel E. Nett, Michael K. Mansour, Bruce S KleinAbstract:(A) Neutrophil gating strategy showing representative lung sample 7 dpi with Blastomyces. (B) Canonical neutrophils (CD11b+, Ly6G+, Ly6Cint, CD11c-), PMN-DCs (CD11b+, Ly6G+, Ly6Cint, CD11c+), and MoDCs (CD11b+, Ly6G-, Ly6C+, CD11c+) were FACS sorted from Blastomyces-infected lungs at day 7 then stained with a Hema3 kit for microscopy. (C-D) Kinetic analysis of neutrophil differentiation after intratracheal challenge with Blastomyces showing relative proportion (C) and absolute numbers (D) of differentiated neutrophils (parent CD11b+, Ly6G+, Ly6Cint); the combined population is the sum of all neutrophils expressing either CD11c or MHC class II. (E-F) Surface expression of neutrophil marker (CXCR2) and antigen-presenting cell markers (MHC class I, CD80, CD86) on neutrophil populations and moDCs (S1C Fig) indicated by histograms (E) and relative expression (F) as indicated by mean fluorescence over fluorescence minus one (FMO) control (gray histogram). (G) Expression of CD64 on neutrophil and MoDC populations. Representative experiments shown; mean±SEM indicated; N = 3–5 mice/group; C-D show representative experiment from 3 kinetic experiments; E-G show representative results from at least two independent experiments at 7 dpi with Blastomyces.
