Coccidioides Immitis Research Articles

Evolution of the mating type locus: insights gained from the dimorphic primary fungal pathogens Histoplasma capsulatum, Coccidioides immitis, and Coccidioides posadasii.

Sexual reproduction of fungi is governed by the mating type (MAT) locus, a specialized region of the genome encoding key transcriptional regulators that direct regulatory networks to specify cell identity and fate. Knowledge of MAT locus structure and evolution has been considerably advanced in recent years as a result of genomic analyses that enable the definition of MAT locus sequences in many species as well as provide an understanding of the evolutionary plasticity of this unique region of the genome. Here, we extend this analysis to define the mating type locus of three dimorphic primary human fungal pathogens, Histoplasma capsulatum, Coccidioides immitis, and Coccidioides posadasii, using genomic analysis, direct sequencing, and bioinformatics. These studies provide evidence that all three species possess heterothallic bipolar mating type systems, with isolates encoding either a high-mobility-group (HMG) domain or an alpha-box transcriptional regulator. These genes are intact in all loci examined and have not been subject to loss or decay, providing evidence that the loss of fertility upon passage in H. capsulatum is not attributable to mutations at the MAT locus. These findings also suggest that an extant sexual cycle remains to be defined in both Coccidioides species, in accord with population genetic evidence. Based on these MAT sequences, a facile PCR test was developed that allows the mating type to be rapidly ascertained. Finally, these studies highlight the evolutionary forces shaping the MAT locus, revealing examples in which flanking genes have been inverted or subsumed and incorporated into an expanding MAT locus, allowing us to propose an expanded model for the evolution of the MAT locus in the phylum Ascomycota.

Epidemiology of central nervous system mycoses

Fungal infections of the central nervous system (CNS) were considered rare until the 1970s. This is no longer true in recent years due to widespread use of corticosteroids, cytotoxic drugs and antibiotics. Immunocompromised patients with underlying malignancy organ transplantations and acquired immune deficiency syndrome are all candidates for acquiring fungal infections either in meninges or brain. A considerable number of cases of CNS fungal infections even in immunocompetent hosts have been reported. A vast array of fungi may cause infection in the CNS, but barring a few, most of them are anecdotal case reports. Cryptococcus neoformans, Candida albicans, Coccidioides immitis. Histoplasma capsulatum are common causes of fungal meningitis; Aspergillus spp, Candida spp, Zygomycetes and some of the melanized fungi are known to cause mass lesions in brain. Few fungi like C. neoformans, Cladophialophora bantiana, Exophiala dermatitidis, Ramichloridium mackenzie, Ochroconis gallopava are considered as true neurotropic fungi. Most of the fungi causing CNS infection are saprobes with worldwide distribution; a few are geographically restricted like Coccidioides immitis. The infections reach the CNS either by the hematogenous route or by direct extension from colonized sinuses or ear canal or by direct inoculation during neurosurgical procedures.

Endobronchial Pseudallescheria boydii in Lung Transplant Patient With Cystic Fibrosis

Emerging fungal pathogens in immunocompromised patients have recently challenged physicians. Aspergillus spp., Coccidioides immitis, Zygomycetes, Candida spp., and Cryptococcus neoformans are the most common fungal pathogens causing endobronchial involvement, with Aspergillus being by far the most c

Coccidioides immitis fungemia: Clinical features and survival in 33 adult patients

Coccidioides immitis is a fungus endemic to the southwestern United States. Susceptible hosts, including blacks, Hispanics, Filipinos, Native Americans, and those with compromised immunity, may develop disseminated disease, including fungemia. We retrospectively reviewed the records of all patients (n = 33) with Coccidioides immitis fungemia (CIF) at a 550-bed public hospital in Phoenix, Arizona, from 1990 to 2002. This is the largest reported series of CIF. The purpose of the study was to review the incidence, signs, symptoms, and outcomes of CIF. Twenty-nine patients had human immunodeficiency virus infection. CIF was associated with sepsis, end-stage alcoholic liver disease, and diabetes in four patients. Survival was poor; 24 of the 33 patients died within 28 days. CIF manifested as a systemic inflammatory response syndrome with progressive cardiorespiratory failure. Despite fluid loading, infusion of vasoactive agents, and mechanical ventilation with positive end-expiratory pressure, patients typically experienced a rapidly progressive course and death. CIF portends an ominous prognosis and typically occurs in the setting of advanced human immunodeficiency virus or medical or surgical crises.

Taxonomic and diagnostic markers for identification ofCoccidioides immitisandCoccidioides posadasii

The ribosomal Internal Transcribed Spacer (ITS) regions of the two recognized species of Coccidioides were studied using a reference set of strains that had been previously identified with species defining microsatellite polymorphisms. Unambiguous identification of the two species proved to be possible by amplifying and sequencing the ITS region. PCR-reactions are sensitive to amplification conditions requiring their careful optimization. Stable amplification and sequencing was achieved with primers ITS3 and 4, enabling species diagnosis. Alternatively, Restriction Fragment Length Polymorphism (RFLP) of the entire ITS region using an annealing temperature of 52 degrees C with the restriction enzymes BsrI and XcmI can also distinguish the species. Three strains typifying the species, Glenospora meteuropaea, G. metamericana and Geotrichum louisianoideum, were analyzed and found to be conspecific with C. posadasii. Although these species have nomenclatural priority over C. posadasii, the latter will be proposed for conservation as it has been included in the US select agent list. In addition, Coccidioides immitis is neotypified in this report. Results of antifungal susceptibility testing did not reveal differences between the two species.

DISSEMINATED COCCIDIOIDOMYCOSIS IN A CAPTIVE INDOCHINESE TIGER (PANTHERA TIGRIS CORBETTI) WITH CHRONIC RENAL DISEASE

A 19-yr-old, 78.2-kg captive female Indochinese tiger (Panthera tigris corbetti) from the El Paso Zoo (El Paso, Texas, USA) with chronic renal disease was euthanized after a 10-day course of anorexia, depression, progressive rear limb weakness, muscle fasciculations, and head tremors. Postmortem findings included pericardial effusion, generalized lymphadenopathy, glomerulosclerosis, glomerular atrophy with membranous glomerulonephropathy, and pancreatic adenocarcinoma. Pyogranulomatous pneumonia, pericarditis, and lymphadenitis were associated with fungal spherules histomorphologically consistent with Coccidioides immitis. Rising antibodies to C. immitis were detected on samples obtained perimortem and 2 mo before euthanasia. Retrospective serology was negative for two additional Indochinese tigers, two Iranian leopards (Panthera pardus saxicolor), two jaguars (Panthera onca), two bobcats (Lynx rufus texensis), two ocelots (Leopardus pardalis), and three Amur leopards (Panthera pardus orientalis) housed at the zoo over an 8-yr period. Despite being located within the endemic region for C. immitis, this is only the second case of coccidioidomycosis reported from this institution.

Statistical modeling of valley fever data in Kern County, California

Coccidioidomycosis (valley fever) is a fungal infection found in the southwestern US, northern Mexico, and some places in Central and South America. The fungus that causes it (Coccidioides immitis) is normally soil-dwelling but, if disturbed, becomes air-borne and infects the host when its spores are inhaled. It is thus natural to surmise that weather conditions that foster the growth and dispersal of the fungus must have an effect on the number of cases in the endemic areas. We present here an attempt at the modeling of valley fever incidence in Kern County, California, by the implementation of a generalized auto regressive moving average (GARMA) model. We show that the number of valley fever cases can be predicted mainly by considering only the previous history of incidence rates in the county. The inclusion of weather-related time sequences improves the model only to a relatively minor extent. This suggests that fluctuations of incidence rates (about a seasonally varying background value) are related to biological and/or anthropogenic reasons, and not so much to weather anomalies.

Molecular Principles of Fungal Pathogenesis

This book offers advanced treatment of a broad selection of topics in molecular medical mycology authored by leading investigators. It assumes a foundation of knowledge of mycotic pathogens and is suitable for the reader who is well-grounded in molecular microbiology. It is highly recommended for investigators planning to conduct medical mycology research. The book is divided into 5 sections: General Principles, Model Systems, Specific Pathogens, The Host, and Future Directions. Only selected highlights are described here because of space limitations. The book reviews the development of transforming and gene-silencing methods for identifying virulence determinants. An overview of Candida albicans virulence underlines that molecular subtyping has elucidated 3 major clades, which differ in their potential for producing superficial versus deep-seated infection. The first step in pathogenesis is adherence to host tissues. The endothelial and epithelial specificity of members of the C. albicans Als family of adherence molecules is defined by the adherence profile of null mutants. The discovery through the genome sequence of C. albicans mating type locus and the delineation of the unique pathway of a parasexual cycle are discussed. Although the population is largely clonal and seems locked in a diploid state, the species has a demonstrated ability to undergo recombination. The phylogenetic species concept has led to a better understanding of the lineage of pathogenic fungi, especially for the mitosporic fungi, which have no known sexual stage. The evolution of fungal species, shown by multilocus sequence typing, enabled construction of a phylogenetic tree of all known fungal pathogens with assignments to well-described families and orders. Mechanisms of resistance to antifungal agents are discussed, including insights from genome sequence analysis and recent clinical observations such as the role of transcription factors in upregulating efflux pumps in the presence of antifungal agents or steroids. How environmental fungi have acquired their pathogenic potential for humans, even those whose immune function is intact, is a puzzle, but clues come from the interaction of fungi with soil-dwelling amebae. Fungi escape endocytosis by converting from yeast to hyphal forms; this not only conditions them for intracellular survival but also suggests how dimorphism may have originated. Transcriptional profiling using microarrays is a powerful tool for identifying genes expressed during mold-to-yeast morphogenesis and host-fungus interactions in infected tissue cultures and biofilms. Interspersed in the book are examples of exploiting this technology to discover key regulatory pathways. No subject attracts more interest, yet is strewn with more pitfalls, than fungal vaccine development. Two major types of vaccine development are preventive vaccines and monoclonal antibody immunotherapy. Individual recombinant antigens have evoked mild to moderate protection. Interest in a potential attenuated live vaccine has been stimulated by the finding that targeted disruption of the Blastomyces dermatitidis gene, which encodes the surface adhesin BAD-1, renders the mutant avirulent. Of the chapters on specific pathogens, the one covering virulence mechanisms in Coccidioides immitis is notable. It discusses application of molecular approaches to identify key proteins expressed during arthroconidial and spherule morphogenesis at each stage of the disease process and to dissect the corresponding interactions with the immune system.

Mycosis Fungoides with Coccidioidomycosis

Mycosis fungoides is an indolent, epidermotropic, cutaneous T-cell lymphoma of helper/memory T cells that presents as heterogeneous, papulosquamous patches, plaques, and tumors. We present a patient with mycosis fungoides and infection with Coccidioides immitis of the skin, which has not been previously reported.

How to diagnose and treat fungal infections in chronic prostatitis

Epidemiologic changes that include immune-compromised patients and drug-resistant fungi have caused an increase in nosocomial infections by Candida albicans and non-albicans Candida species. Other fungi, aspergilla and Cryptococcus (environmental contaminants), are opportunistic invaders of the immune-compromised (transplant, HIV) patients. The environmental fungi Coccidioides immitis (dry arid areas), Histoplasma capsulatum (Avian-infested areas), and Blastomyces dermatitidis (aquatic areas) can cause infections in immune-competent and immune-deficient patients. Each fungus can cause changes in the prostate that mimic bacterial infection, benign prostatic hypertrophy, or neoplasm. Diagnosis can be established by urine cultures or needle biopsy of the prostate. Prostate surgery for carcinoma or benign enlargement may detect latent fungal infection. Different fungal species can have divergent clinical manifestations and require different treatment. In some cases, asymptomatic localized fungal prostatitis can be cured by removal of the infected gland. Symptomatic and disseminated infection may require prostatectomy and systemic antifungal therapy.

A phylogenomic analysis of the Ascomycota

An automated procedure was developed to extract orthologous sequences from fungal genomes and incorporate them into phylogenomic analyses in a timely and efficient manner. This approach involves parsing an all versus all BLASTP search of 17 proteomes and creating a similarity matrix from e-values, which is then used to cluster proteins into related groups by means of a Markov Clustering algorithm. After performing this analysis at different stringency levels, 854 single copy protein clusters, which were ubiquitously distributed in all 17 proteomes, were identified. These clusters were culled to include only those clusters where all proteins had best hits to and received hits from a protein within the same cluster. The final data set included gapless alignments for 781 clusters of orthologous sequences that were concatenated into one super alignment containing 195,664 amino acid characters. Neighbor-joining distance and maximum likelihood analyses resulted in identical topologies and all except one node received 100% bootstrap support. The node supporting Stagonospora nodorum’s position received 83% support or higher; it was also the only taxon differentially resolved in the maximum parsimony analyses. All analyses resolved the two derived subphyla Pezizomycotina and Saccharomycotina, and Schizosaccharomyces pombe as an early diverging lineage of the Ascomycota. Importantly, these analyses resolved the Leotiomycetes as the sister group to the Sordariomycetes, a region of the Ascomycota phylogeny that has remained problematic in molecular phylogenetic studies of more limited character sampling. Additional phylogenetic analyses which included orthologous sequences from an unannotated ascomycotan genome (e.g., Coccidioides immitis) and subsets of orthologs with different characteristics supported this topology. Phylogenetic analyses of the 595 orthologs which included C. immitis resulted in an identical topology to the previous 781 ortholog analysis and correctly placed C. immitis in the Eurotiomycetes. This demonstrated the correct identification of orthologs and the ability to incorporate unannotated genomic data into a common phylogenetic analysis.

Viability and molecular authentication of Coccidioides immitis strains from culture collection of the Instituto Oswaldo Cruz, Rio de Janeiro, Brazil

Twenty Coccidioides immitis strains were evaluated. Only 5 of the 20 strains kept under mineral oil maintained their viability while all 5 subcultures preserved in water remained viable and none of the 13 subcultures kept in soil were viable. A 519 bp PCR product from the csa gene confirmed the identity of the strains.

Midfoot Coccidioidal Osteomyelitis: A Case Report and Review of the Literature

Coccidioides immitis is endemic in arid parts of the southwestern United States and regions of Central and South America. Symptomatic infection (comprising 40% of cases) initially presents as a flu-like illness with fever, cough, headache, rash, and myalgias. Some patients (especially those who are immunocompromised) fail to recover, with the development of chronic pulmonary infection or widespread disseminated infection1. A Coccidioides immitis infection that is disseminated to bone is very difficult to treat and usually requires lifetime suppressive antifungal therapy1-3. The present report describes a patient with recurrent osseous coccidioidal osteomyelitis at a new locus who presented after minor trauma to the middle part of the foot. The patient was managed successfully with surgical debridement and antifungal medication. The pathophysiology of osseous infection and treatment options are discussed. The patient was informed that data concerning this case would be submitted for publication. Six years prior to presentation, a thirty-nine-year-old man was diagnosed with disseminated coccidioidomycosis involving the thoracic vertebrae, skin, and lungs. The diagnosis was made on the basis of a biopsy of lung tissue. At the time of diagnosis, the Coccidioides complement fixation titer was 1:2048. The patient was managed with amphotericin B (total dose, 1.5 g) and high-dose fluconazole. Approximately eighteen months before admission, fluconazole was discontinued when the Coccidioides titers returned to normal (<1:2). Six months prior to presentation, the patient sustained a minor nonpenetrating injury that resulted in pain and tenderness in the lateral aspect of the right foot, with a recurrent nonhealing wound. The injury initially was thought to have resolved without treatment, but two months later another lesion recurred in the same region. Over the subsequent four months, the patient was seen at multiple clinics and was managed with several courses of antimicrobial medication, without healing of the …

Etanercept treatment of cutaneous granulomas in common variable immunodeficiency

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by hypogammaglobulinemia, poor antibody responses, and recurrent bacterial infections, usually of the sinorespiratory tract. A not uncommon complication is granuloma of the lungs, spleen, liver, and/or skin. We report the case of an 18-year-old boy with CVID and chronic granulomas of the left arm (since 13 years of age) refractory to treatment with antibiotics, intravenous immunoglobulin, antifungal agents, systemic and intralesional steroids, IFN-gamma, cyclosporine, methotrexate, hydroxychloroquine, localized radiation therapy, and surgical excision. The lesions improved after treatment with the systemic administration of the TNF-alpha inhibitor etanercept for 1 year. Etanercept prevents soluble TNF from binding to its cell membrane receptor, leading to inhibition of its inflammatory cascade. We recommend further trials of etanercept in patients with CVID with noninfectious recalcitrant granulomas.

Fungal Infections of the Spine

Fungal infections of the spine are relatively uncommon. Fungi such as Coccidioides immitis and Blastomyces dermatitidis are limited to specific geographical areas whereas cryptococcus, candida, and aspergillus are found worldwide. Candida and aspergillus are normal commensals of the body and produce disease in susceptible organisms when they gain access to the vascular system through intravenous lines, during implantation of prosthetic devices, or during surgery. For the other fungi, spinal involvement usually is the result of hematogenous or direct spread of organisms from an initial pulmonary source of infection. Involvement of the vertebral bodies can lead to vertebral compression fractures and gross deformity of the spine. Spread of infection along the anterior longitudinal ligament can lead to psoas or paravertebral abscesses. Early recognition of the disease requires a high index of suspicion, proper travel history, and a detailed physical examination. Treatment relies on the prompt institution of appropriate pharmacotherapy and constant monitoring of clinical progress. Resistance to medical therapy, spinal instability, and neurologic deficits are indications for débridement and stabilization with spinal fusion. Prognosis depends on the premorbid state of the patient, the type of fungal organism, and the timing of treatment. Level V (expert opinion). Please see the Guidelines for Authors for a complete description of levels of evidence.

Phylogenetic and evolutionary aspects of Paracoccidioides brasiliensis reveal a long coexistence with animal hosts that explain several biological features of the pathogen

The habitat of the mycelial saprobic form of Paracoccidioides brasiliensis, which produces the infectious propagula, has not been determined and has proven difficult for mycologists to describe. The fungus has been rarely isolated from the environment, the disease has a prolonged latency period and no outbreaks have been reported. These facts have precluded the adoption of preventive measures to avoid infection. The confirmation of natural infections in nine-banded armadillos ( Dasypus novemcinctus) with P. brasiliensis, in high frequency and wide geographic distribution, has opened new avenues for the study and understanding of its ecology. Armadillos belong to the order Xenarthra, which has existed in South America ever since the Paleocene Era (65 million years ago), when the South American subcontinent was still a detached land, before the consolidation of what is now known as the American continent. On the other hand, strong molecular evidence suggests that P. brasiliensis and other dimorphic pathogenic fungi – such as Blastomyces dermatitidis, Coccidioides immitis and Histoplasma capsulatum – belong to the family Onygenaceae sensu lato (order Onygenales, Ascomycota), which appeared around 150 million years ago. P. brasiliensis ecology and relation to its human host are probably linked to the fungal evolutionary past, especially its long coexistence with and adaptation to animal hosts other than Homo sapiens, of earlier origin. Instead of being a blind alley, the meaning of parasitism for dimorphic pathogenic fungi should be considered as an open two-way avenue, in which the fungus may return to the environment, therefore contributing to preserve its teleomorphic (sexual) and anamorphic (asexual) forms in a defined and protected natural habitat.

Temporal expression of inflammatory mediators in brain basilar artery vasculitis and cerebrospinal fluid of rabbits with coccidioidal meningitis.

Strokes due to transmural vasculitis associated with coccidioidal meningitis result in significant morbidity and mortality. The immunological and inflammatory processes responsible are poorly understood. To determine the inflammatory mediators, i.e. cytokines, chemokines, iNOS, matrix metalloproteinase-9 (MMP-9), that possibly contribute to vasculitis, temporal mRNA expression in brain basilar artery samples and MMP-9 protein in the CSF of male NZW rabbits infected intracisternally with 6.5 x 10(4) arthroconidia of Coccidioides immitis were assessed. Five infected and 3 sham-injected rabbits at each time point were euthanized 4, 9, 14 and 20 days post infection. All infected rabbits had neurological abnormalities and severe vasculitis in the basilar arteries on days 9-20. In basilar arteries of infected animals versus controls, mRNAs encoding for IL-6, iNOS, IFN-gamma, IL-2, MCP-1, IL-1beta, IL-10, TNF-alpha, CCR-1, MMP-9, TGF-beta, as well as MMP-9 protein in CSF, were found to be significantly up-regulated. Thus, this study identified inflammatory mediators associated with CNS vasculitis and meningitis due to C. immitis infection. Assessment of the individual contribution of each mediator to vasculitis may offer novel approaches to the treatment of coccidioidal CNS infection. This study also provides unique methodology for immunology studies in a rabbit model.

A retrospective study of cutaneous equine sarcoidosis and its potential infectious aetiological agents

Nine horses from ages 5 to 21 years were diagnosed with cutaneous equine sarcoidosis (ES) over an 18-year period. In addition to skin, the lungs were frequently involved, with other organ systems affected less commonly. A predisposition for thoroughbreds and geldings was noted. Cutaneous lesions and signs included crusts, scales, alopecia and pruritus. These were found at various sites, particularly the legs/thighs/elbows, thorax, neck, face and ventral abdomen. Three horses were euthanized shortly after hospitalization; others survived as long as 12 years. Histopathologic stains, immunohistochemistry and polymerase chain reaction assays on paraffin-embedded cutaneous specimens from eight horses for Mycobacterium spp., Coccidioides immitis, Cryptococcus neoformans, Corynebacterium pseudotuberculosis, and Borrelia burgdorferi were all negative. The aetiology of ES is unlikely microbial and continues to be a diagnosis of exclusion. ES, when limited to the skin, is associated with a good prognosis, with either partial or complete response to glucocorticoid therapy in all the surviving horses.

Unusual Forms of Immature Sporulating Coccidioides immitis Diagnosed by Fine-Needle Aspiration Biopsy

Coccidioidomycosis is an endemic infection acquired by inhalation of the spores (arthroconidia) of the thermally dimorphic fungus, Coccidioides immitis. The arthroconidia transform into spherical cells called mature spherules in the lung. Immature spherules and other atypical forms of immature C immitis have rarely been found in vivo. We report on a case that presented unusual forms of immature sporulating C immitis in a fine-needle aspiration specimen. A 36-year-old Chinese woman, living in New Jersey for the past 10 years, presented with fever, night sweats, hemoptysis, and an abnormal chest radiograph approximately 9 months after a brief vacation trip to the Grand Canyon in Arizona. She was treated with antibiotics for 4 weeks without improvement. Subsequent chest computed tomography showed a 3-cm cavitary lesion in the right lower lobe of the lung. Fine-needle aspiration biopsy revealed diverse morphologic forms of a fungus that was confirmed by culture as immature sporulating C immitis.

Fungal heat-shock proteins in human disease

Heat-shock proteins (hsps) have been identified as molecular chaperones conserved between microbes and man and grouped by their molecular mass and high degree of amino acid homology. This article reviews the major hsps of Saccharomyces cerevisiae, their interactions with trehalose, the effect of fermentation and the role of the heat-shock factor. Information derived from this model, as well as from Neurospora crassa and Achlya ambisexualis, helps in understanding the importance of hsps in the pathogenic fungi, Candida albicans, Cryptococcus neoformans, Aspergillus spp., Histoplasma capsulatum, Paracoccidioides brasiliensis, Trichophyton rubrum, Phycomyces blakesleeanus, Fusarium oxysporum, Coccidioides immitis and Pneumocystis jiroveci. This has been matched with proteomic and genomic information examining hsp expression in response to noxious stimuli. Fungal hsp90 has been identified as a target for immunotherapy by a genetically recombinant antibody. The concept of combining this antibody fragment with an antifungal drug for treating life-threatening fungal infection and the potential interactions with human and microbial hsp90 and nitric oxide is discussed.