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Bridget M Barker - One of the best experts on this subject based on the ideXlab platform.

  • Lifecycle dominates the volatilome character of the dimorphic fungus Coccidioides spp.
    2021
    Co-Authors: Emily A. Higgins Keppler, Bridget M Barker, Heather L Mead, Heather D. Bean
    Abstract:

    Valley fever (coccidioidomycosis) is an endemic fungal pneumonia of the North and South American deserts. The causative agents of Valley fever are the dimorphic fungi Coccidioides immitis and C. posadasii, which grow as mycelia in the environment and spherules within the lungs of vulnerable hosts. The current diagnostics for Valley fever are severely lacking due to poor sensitivity and invasiveness, contributing to a 23-day median time-to-diagnosis, and therefore new diagnostic tools are needed. We are working toward the development of a breath-based diagnostic for coccidioidomycosis, and in this initial study we characterized the volatile metabolomes (or volatilomes) of in vitro cultures of Coccidioides. Using solid-phase microextraction and comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC–TOFMS), we characterized the VOCs produced by six strains of each species during mycelial or spherule growth. We detected a total of 353 VOCs that were at least two-fold more abundant in a Coccidioides culture versus medium controls and found the volatile metabolome of Coccidioides is more dependent on growth phase (spherule versus mycelia) than on the species. The volatile profiles of C. posadasii and C. immitis have strong similarities, indicating that a single suite of Valley fever breath biomarkers can be developed to detect both species.

  • Structural characterization and evolutionary analyses of the Coccidioides immitis and Coccidioides posadasii mitochondrial genomes
    2020
    Co-Authors: Marcus De Melo Teixeira, Jason E Stajich, B Franz Lang, Daniel R Matute, Bridget M Barker
    Abstract:

    Fungal mitochondrial genomes encode for genes involved in crucial cellular processes, such as oxidative phosphorylation and mitochondrial translation, and these genes have been used as molecular markers for population genetics studies. Coccidioides immitis and C. posadasii are endemic fungal pathogens that cause coccidioidomycosis in arid regions across both American continents. To date, almost one hundred Coccidioides strains have been sequenced. The focus of these studies has been exclusively to infer patterns of variation of nuclear genomes (nucDNA). However, their mitochondrial genomes (mtDNA) have not been studied. In this report, we describe the assembly and annotation of mitochondrial reference genomes for two representative strains of C. posadasii and C. immitis, as well as assess population variation among 77 published genomes. The circular-mapping mtDNA molecules are 68.2 Kb in C. immitis and 75.1 Kb in C. posadasii. We identified the fourteen mitochondrial protein-coding genes common to most fungal mitochondria, including genes encoding the small and large ribosomal RNAs (rns and rnl), the RNA subunit of RNAse P (rnpB), and 26 tRNAs organized in polycistronic transcription units, which are mostly syntenic across different populations and species of Coccidioides. Both Coccidioides species are characterized by a large number of group I and II introns, harboring twice the number of elements as compared to closely related Onygenales. The introns contain complete or truncated ORFs with high similarity to homing endonucleases of the LAGLIDADG and GIY-YIG families. Phylogenetic comparison of the mtDNA and nucDNA genomes shows discordance, possibly due to differences in patterns of inheritance. In summary, this work represents the first complete assessment of mitochondrial genomes among several isolates of both species of Coccidioides, and provides a foundation for future functional work.

  • investigating the role of animal burrows on the ecology and distribution of Coccidioides spp in arizona soils
    Mycopathologia, 2019
    Co-Authors: Daniel R Kollath, Marcus De Melo Teixeira, Aubrey L Funke, Karis J Miller, Bridget M Barker
    Abstract:

    The lack of knowledge regarding the ecology of Coccidioides spp. makes both modeling the potential for disease outbreaks and predicting the distribution of the organism in the environment challenging. No single ecological parameter explains the biogeography of the pathogen. Previous investigations suggest an association with desert mammals, but these results should be confirmed with modern molecular techniques. Therefore, we used molecular tools to analyze soils associated with animal activity (i.e., burrows) to better define the ecology and biogeography of Coccidioides spp. in Arizona. Soils were collected from locations predicted to have favorable habitat outside of the established endemic regions to better understand the ecological niche of the organism in this state. Our central hypothesis is that soils taken from within animal burrows will have a higher abundance of Coccidioides spp. when compared to soils not directly associated with animal burrows. Our results show that there is a positive relationship with Coccidioides spp. and animal burrows. The organism was detected in two locations in northern Arizona at sites not known previously to harbor the fungus. Moreover, this fungus is able to grow on keratinized tissues (i.e., horse hair). These results provide additional evidence that there is a relationship between Coccidioides spp. and desert animals, which sheds new light on Coccidioides' ecological niche. These results also provide evidence that the geographic range of the organism may be larger than previously thought, and the concept of endemicity should be reevaluated for Coccidioides.

  • the rise of Coccidioides forces against the dust devil unleashed
    Frontiers in Immunology, 2019
    Co-Authors: Marley Caballero C Van Dyke, George Richard Thompson, John N Galgiani, Bridget M Barker
    Abstract:

    Coccidioidomycosis (Valley fever) is a fungal disease caused by the inhalation of Coccidioides posadasii or C. immitis. This neglected disease occurs in the desert areas of the western United States, most notably in California and Arizona, where infections continue to rise. Clinically, coccidioidomycosis ranges from asymptomatic to severe pulmonary disease and can disseminate to the brain, skin, bones, and elsewhere. New estimates suggest as many as 350,000 new cases of coccidioidomycosis occur in the United States each year. Thus, there is an urgent need for the development of a vaccine and new therapeutic drugs against Coccidioides infection. In this review, we discuss the battle against Coccidioides including the development of potential vaccines, the quest for new therapeutic drugs, and our current understanding of the protective host immune response to Coccidioides infection.

  • improved reference genome sequence of Coccidioides immitis strain wa_211 isolated in washington state
    Microbiology resource announcements, 2019
    Co-Authors: Marcus De Melo Teixeira, Bridget M Barker, Jason E Stajich
    Abstract:

    Author(s): Teixeira, Marcus de Melo; Barker, Bridget Marie; Stajich, Jason E | Abstract: Coccidioides fungi are widely distributed in the American continents, with an expanding western range documented by a recently discovered cryptic population of Coccidioides immitis in Washington State. The assembled and annotated reference genome sequence of the soil-derived C. immitis strain WA_211 will support population and functional genomics studies.

Marcus De Melo Teixeira - One of the best experts on this subject based on the ideXlab platform.

  • The mitochondrial genomes of the human pathogens Coccidioides immitis and C. posadasii
    G3 Genes|Genomes|Genetics, 2021
    Co-Authors: Marcus De Melo Teixeira, Jason E Stajich, B Franz Lang, Daniel R Matute, Bridget Barker
    Abstract:

    Abstract Fungal mitochondrial genomes encode genes involved in crucial cellular processes, such as oxidative phosphorylation and mitochondrial translation, and the molecule has been used as a molecular marker for population genetics studies. Coccidioides immitis and C. posadasii are endemic fungal pathogens that cause coccidioidomycosis in arid regions across both American continents. To date, approximately 150 Coccidioides isolates have been sequenced to infer patterns of variation of nuclear genomes. However, less attention has been given to the mitochondrial genomes of Coccidioides. In this report, we describe the assembly and annotation of mitochondrial reference genomes for two representative strains of C. posadasii and C. immitis, as well as assess population variation among 77 selected genomes. The sizes of the circular-mapping molecules are 68.2 Kb in C. immitis and 75.1 Kb in C. posadasii. We identify fourteen mitochondrial protein-coding genes common to most fungal mitochondria, which are largely syntenic across different populations and species of Coccidioides. Both Coccidioides species are characterized by a large number of group I and II introns, harboring twice the number of elements as compared to closely related Onygenales. The introns contain complete or truncated ORFs with high similarity to homing endonucleases of the LAGLIDADG and GIY-YIG families. Phylogenetic comparisons of mitochondrial and nuclear genomes show extensive phylogenetic discordance suggesting that the evolution of the two types of genetic material is not identical. This work represents the first assessment of mitochondrial genomes among isolates of both species of Coccidioides, and provides a foundation for future functional work.

  • Structural characterization and evolutionary analyses of the Coccidioides immitis and Coccidioides posadasii mitochondrial genomes
    2020
    Co-Authors: Marcus De Melo Teixeira, Jason E Stajich, B Franz Lang, Daniel R Matute, Bridget M Barker
    Abstract:

    Fungal mitochondrial genomes encode for genes involved in crucial cellular processes, such as oxidative phosphorylation and mitochondrial translation, and these genes have been used as molecular markers for population genetics studies. Coccidioides immitis and C. posadasii are endemic fungal pathogens that cause coccidioidomycosis in arid regions across both American continents. To date, almost one hundred Coccidioides strains have been sequenced. The focus of these studies has been exclusively to infer patterns of variation of nuclear genomes (nucDNA). However, their mitochondrial genomes (mtDNA) have not been studied. In this report, we describe the assembly and annotation of mitochondrial reference genomes for two representative strains of C. posadasii and C. immitis, as well as assess population variation among 77 published genomes. The circular-mapping mtDNA molecules are 68.2 Kb in C. immitis and 75.1 Kb in C. posadasii. We identified the fourteen mitochondrial protein-coding genes common to most fungal mitochondria, including genes encoding the small and large ribosomal RNAs (rns and rnl), the RNA subunit of RNAse P (rnpB), and 26 tRNAs organized in polycistronic transcription units, which are mostly syntenic across different populations and species of Coccidioides. Both Coccidioides species are characterized by a large number of group I and II introns, harboring twice the number of elements as compared to closely related Onygenales. The introns contain complete or truncated ORFs with high similarity to homing endonucleases of the LAGLIDADG and GIY-YIG families. Phylogenetic comparison of the mtDNA and nucDNA genomes shows discordance, possibly due to differences in patterns of inheritance. In summary, this work represents the first complete assessment of mitochondrial genomes among several isolates of both species of Coccidioides, and provides a foundation for future functional work.

  • investigating the role of animal burrows on the ecology and distribution of Coccidioides spp in arizona soils
    Mycopathologia, 2019
    Co-Authors: Daniel R Kollath, Marcus De Melo Teixeira, Aubrey L Funke, Karis J Miller, Bridget M Barker
    Abstract:

    The lack of knowledge regarding the ecology of Coccidioides spp. makes both modeling the potential for disease outbreaks and predicting the distribution of the organism in the environment challenging. No single ecological parameter explains the biogeography of the pathogen. Previous investigations suggest an association with desert mammals, but these results should be confirmed with modern molecular techniques. Therefore, we used molecular tools to analyze soils associated with animal activity (i.e., burrows) to better define the ecology and biogeography of Coccidioides spp. in Arizona. Soils were collected from locations predicted to have favorable habitat outside of the established endemic regions to better understand the ecological niche of the organism in this state. Our central hypothesis is that soils taken from within animal burrows will have a higher abundance of Coccidioides spp. when compared to soils not directly associated with animal burrows. Our results show that there is a positive relationship with Coccidioides spp. and animal burrows. The organism was detected in two locations in northern Arizona at sites not known previously to harbor the fungus. Moreover, this fungus is able to grow on keratinized tissues (i.e., horse hair). These results provide additional evidence that there is a relationship between Coccidioides spp. and desert animals, which sheds new light on Coccidioides' ecological niche. These results also provide evidence that the geographic range of the organism may be larger than previously thought, and the concept of endemicity should be reevaluated for Coccidioides.

  • improved reference genome sequence of Coccidioides immitis strain wa_211 isolated in washington state
    Microbiology resource announcements, 2019
    Co-Authors: Marcus De Melo Teixeira, Bridget M Barker, Jason E Stajich
    Abstract:

    Author(s): Teixeira, Marcus de Melo; Barker, Bridget Marie; Stajich, Jason E | Abstract: Coccidioides fungi are widely distributed in the American continents, with an expanding western range documented by a recently discovered cryptic population of Coccidioides immitis in Washington State. The assembled and annotated reference genome sequence of the soil-derived C. immitis strain WA_211 will support population and functional genomics studies.

  • Improved Reference Genome Sequence of Coccidioides immitis Strain WA_211, Isolated in Washington State.
    Microbiology resource announcements, 2019
    Co-Authors: Marcus De Melo Teixeira, Bridget M Barker, Jason E Stajich
    Abstract:

    Coccidioides fungi are widely distributed in the American continents, with an expanding western range documented by a recently discovered cryptic population of Coccidioides immitis in Washington State. The assembled and annotated reference genome sequence of the soil-derived C. immitis strain WA_211 will support population and functional genomics studies.

Harry R. Hill - One of the best experts on this subject based on the ideXlab platform.

Nancy L. Wengenack - One of the best experts on this subject based on the ideXlab platform.

  • the utility of Coccidioides polymerase chain reaction testing in the clinical setting
    Mycopathologia, 2010
    Co-Authors: D Vucicevic, Janis E. Blair, Holenarasipur R. Vikram, Matthew J. Binnicker, Ann E. Mccullough, Shimon Kusne, James M Parish, Nancy L. Wengenack
    Abstract:

    Coccidioidomycosis, the fungal infection caused by dimorphic Coccidioides sp., is typically diagnosed by histopathologic identification of spherules in affected secretions and tissues or by culture. These tests are reliable but time-intensive, delaying diagnosis and treatment. To evaluate a polymerase chain reaction (PCR) test developed to detect Coccidioides sp. in clinical specimens, we conducted a retrospective chart review of all patients (N = 145) who underwent Coccidioides PCR at our institution between April 27, 2007, and May 6, 2008, abstracting clinical, microbiologic, serologic, radiographic, treatment, and follow-up data. One hundred fifty-eight PCR tests (153 respiratory; 5 cerebrospinal fluid) produced 5 positive and 153 negative findings. Five of nine patients (56%) with confirmed or highly probable pulmonary coccidioidomycosis had a positive PCR on respiratory specimens, and four of nine (44%) had a positive culture. Among two patients with coccidioidal meningitis, none had a positive PCR, whereas Coccidioides sp. in fungal culture grew for one of two. Among six asymptomatic patients with probable coccidioidomycosis, none had a positive culture or PCR. Compared with culture of respiratory specimens, PCR demonstrated a sensitivity, specificity, positive predictive value, and negative predictive value of 75, 99, 60, and 99%, respectively. Coccidioides PCR appears accurate in identifying negative results, and its sensitivity is similar to that of fungal culture.

  • Detection of Coccidioides Species in Clinical Specimens by Real-Time PCR
    Journal of clinical microbiology, 2006
    Co-Authors: Matthew J. Binnicker, Seanne P. Buckwalter, Justin J. Eisberner, R. A. Stewart, Ann E. Mccullough, Sherri L. Wohlfiel, Nancy L. Wengenack
    Abstract:

    Coccidioides spp. are dimorphic fungal pathogens endemic to the semiarid regions of North, Central, and South America. Currently, direct smear and culture are the most common means of identifying Coccidioides spp. While these methods offer relatively sensitive and specific means of detecting Coccidioides spp., growth in culture may take up to 3 weeks, potentially delaying the diagnosis and initiation of appropriate antifungal therapy. In addition, growth of the organism represents a significant safety risk to laboratory personnel. The need for a rapid and safe means of diagnosing coccidioidomycosis prompted us to develop a real-time PCR assay to detect Coccidioides spp. directly from clinical specimens. Primers and fluorescent resonance energy transfer (FRET) probes were designed to target the internal transcribed spacer 2 region of Coccidioides. The assay's limit of detection is below 50 targets per reaction. An analysis of 40 Coccidioides sp. clinical isolates grown in culture demonstrated 100% sensitivity of the assay. A cross-reactivity panel containing fungi, bacteria, mycobacteria, and viruses was tested and demonstrated 100% specificity for Coccidioides spp. An analysis of 266 respiratory specimens by LightCycler PCR demonstrated 100% sensitivity and 98.4% specificity for Coccidioides spp. compared with culture. Analysis of 66 fresh tissue specimens yielded 92.9% sensitivity and 98.1% specificity versus those of the culture method. The sensitivity of the assay testing 148 paraffin-embedded tissue samples is 73.4%. A rapid method for the detection of Coccidioides spp. directly from clinical material will greatly assist in the timely diagnosis and treatment of patients, while at the same time decreasing the risk of accidental exposure to laboratory personnel.

Esperanza Duarte-escalante - One of the best experts on this subject based on the ideXlab platform.

  • Design and evaluation of an AFLP molecular marker for the detection of Coccidioides spp. in biological samples.
    The Brazilian journal of infectious diseases : an official publication of the Brazilian Society of Infectious Diseases, 2019
    Co-Authors: María Del Rocío Reyes-montes, María Guadalupe Frías-de-león, Isai Victoriano-pastelín, Gustavo Acosta-altamirano, Esperanza Duarte-escalante
    Abstract:

    Abstract At present, there is no standardized marker that is routinely used in clinical laboratories to diagnose coccidioidomycosis. Thus, the goals of this study were to obtain a sequence characterized amplified region (SCAR) marker for the identification of Coccidioides spp., evaluate its specificity and sensitivity in fungal DNA-spiked blood and sputum samples, and compare it with previously described molecular markers. Specific amplified fragment length polymorphism (AFLP) amplicons for Coccidioides immitis and Coccidioides posadasii were cloned into the vector pGEM® -T Easy vector and sequenced to develop a SCAR marker. Oligonucleotides were designed to identify Coccidioides spp. by polymerase chain reaction (PCR), and the specificity and sensitivity of these oligonucleotides were tested with the DNA from related pathogens. The specificity and sensitivity of the SCAR marker was evaluated with blood and sputum samples spiked with Coccidioides DNA and compared with other previously described markers (621, GAC2, and Ag2/PRA). In addition, the conditions for its use were established using biological samples. A specific marker named SCAR300 was obtained to identify Coccidioides spp. that exhibited good sensitivity and specificity. The results showed that all of the markers tested in this study can identify Coccidioides spp. However, the SCAR300 and 621 markers were the most sensitive, whereas the SCAR300 marker was the most specific. Thus, the SCAR300 marker is a useful tool to identify Coccidioides spp.

  • The habitat of Coccidioides spp. and the role of animals as reservoirs and disseminators in nature.
    BMC infectious diseases, 2016
    Co-Authors: María Del Rocío Reyes-montes, María Guadalupe Frías-de-león, María Ameyali Pérez-huitrón, Jorge Luis Ocaña-monroy, Erick Martínez-herrera, Roberto Arenas, Esperanza Duarte-escalante
    Abstract:

    Coccidioidomycosis, a potentially fatal fungal infection, is considered an emergent mycotic disease because of the increased incidence of fungal infections registered over recent years. Infection occurs through the inhalation of arthroconidia from two main species of Coccidioides: Coccidioides immitis and C. posadasii, which are both endemic to arid and semi-arid regions of North America. Coccidioides species not only infect humans but can also infect other mammals (land, aquatic, wild or domestic), reptiles and birds. To obtain information regarding the habitat of Coccidioides spp. and the animals infected by this fungus and to identify the role that infected animals play as reservoirs and disseminators of this fungus in nature. A literature review was conducted to identify the habitat of Coccidioides spp. and the infected non-human animal species targeted by this fungus. This review allows us to suggest that Coccidioides spp. may be classified as halotolerant organisms; nevertheless, to perpetuate their life cycle, these organisms depend on different animal species (reservoirs) that serve as a link with the environment, by acting as disseminators of the fungi in nature.

  • The habitat of Coccidioides spp. and the role of animals as reservoirs and disseminators in nature
    BMC Infectious Diseases, 2016
    Co-Authors: María Del Rocío Reyes-montes, María Guadalupe Frías-de-león, María Ameyali Pérez-huitrón, Jorge Luis Ocaña-monroy, Erick Martínez-herrera, Roberto Arenas, Esperanza Duarte-escalante
    Abstract:

    Background Coccidioidomycosis, a potentially fatal fungal infection, is considered an emergent mycotic disease because of the increased incidence of fungal infections registered over recent years. Infection occurs through the inhalation of arthroconidia from two main species of Coccidioides : Coccidioides immitis and C. posadasii , which are both endemic to arid and semi-arid regions of North America. Coccidioides species not only infect humans but can also infect other mammals (land, aquatic, wild or domestic), reptiles and birds. Objective To obtain information regarding the habitat of Coccidioides spp. and the animals infected by this fungus and to identify the role that infected animals play as reservoirs and disseminators of this fungus in nature. Materials A literature review was conducted to identify the habitat of Coccidioides spp. and the infected non-human animal species targeted by this fungus. Results and conclusions This review allows us to suggest that Coccidioides spp. may be classified as halotolerant organisms; nevertheless, to perpetuate their life cycle, these organisms depend on different animal species (reservoirs) that serve as a link with the environment, by acting as disseminators of the fungi in nature.

  • AFLP analysis reveals high genetic diversity but low population structure in Coccidioides posadasii isolates from Mexico and Argentina
    BMC infectious diseases, 2013
    Co-Authors: Esperanza Duarte-escalante, Gerardo Zúñiga, María Guadalupe Frías-de-león, Cristina Elena Canteros, Laura Rosio Castañón-olivares, María Rocío Del Reyes-montes
    Abstract:

    Background Coccidioides immitis and C. posadasii cause coccidioidomycosis, a disease that is endemic to North and South America, but for Central America, the incidence of coccidioidomycosis has not been clearly established. Several studies suggest genetic variability in these fungi; however, little definitive information has been discovered about the variability of Coccidioides fungi in Mexico (MX) and Argentina (AR). Thus, the goals for this work were to study 32 Coccidioides spp. isolates from MX and AR, identify the species of these Coccidioides spp. isolates, analyse their phenotypic variability, examine their genetic variability and investigate the Coccidioides reproductive system and its level of genetic differentiation.