Genomic Epidemiology of Large Blastomycosis Outbreak, Ontario, Canada, 2021.

Using phylogenomic analysis, we provide genomic epidemiology analysis of a large blastomycosis outbreak in Ontario, Canada, caused by Blastomyces gilchristii. The outbreak occurred in a locale where blastomycosis is rarely diagnosed, signaling a possible shift in geographically associated incidence patterns. Results elucidated fungal population genetic structure, enhancing understanding of the outbreak.

Detection of Histoplasma capsulatum and Blastomyces dermatitidis antigens in serum using a single quantitative enzyme immunoassay.

Histoplasma and Blastomyces antigen detection assays are commonly used diagnostic tools. However, a high level of cross-reactivity between these antigens prevents definitive pathogen identification by these assays alone. Retrospective analysis of 3,529 patients with Histoplasma and Blastomyces antigen testing performed on the same serum sample yielded an overall percent agreement of 99.3% (3,506 of 3,529; kappa: 0.859) between the two assays, suggesting that use of a single assay to detect both antigens may be an alternative diagnostic approach. We assessed performance of the Gotham BioTech Blastomyces antigen (GBA) enzyme immunoassay (EIA) (Portland, Maine) for detection of Blastomyces and Histoplasma antigens in serum. Comparison to the MiraVista Diagnostics Blastomyces (MVB) EIA showed 100% positive (24 of 24), negative (57 of 57), and overall (81 of 81) percent agreement. Additionally, 171 sera were used to compare the GBA EIA to the MiraVista Diagnostics Histoplasma (MVH) EIA, which showed 91.3% (63 of 69), 98% (100 of 102), and 95.3% (163 of 171) positive, negative, and overall percent agreement, respectively. Among eight patients with discordant GBA/MVH EIA results, seven had additional fungal testing performed, and results suggested that the MVH and GBA results were inaccurate for two and five samples, respectively. Overall, this study suggests that the GBA EIA has a high level of agreement with both of the commonly used, individual Blastomyces and Histoplasma antigen EIAs. By taking advantage of the high level of cross-reactivity between Blastomyces and Histoplasma antigen EIAs, utilization of a single antigen detection assay for these fungi provides an opportunity to optimize test utilization and decrease patient cost while maintaining a high level of diagnostic accuracy.

Detection of Blastomyces gilchristii via metagenomic sequencing in outbreak-associated soils.

Cases of blastomycosis, a serious fungal disease globally rare but endemic to North America, can appear both sporadically and in outbreaks. Tracing these outbreaks to their environment has traditionally used culturing and polymerase chain reaction. Here, we present our method for metagenomic detection of Blastomyces in a 2015 outbreak soil sample from central Wisconsin. By sequencing this sample to multiple depths, we simulated the minimum required depth to detect Blastomyces in this outbreak. Our methods and recommendations can be used to identify the sources of blastomycosis during outbreaks and to learn about the ecology of Blastomyces.

Clinical Presentation of Blastomycosis is Associated With Infecting Species, Not Host Genotype.

Objective: To determine if host genetics may be a risk factor for severe blastomycosis.Design: A cohort of patients who had contracted blastomycosis underwent targeted SNP (single nucleotide polymorphism) genotyping. The genetics of these patients were compared to a set of age and gender-matched controls and between patients with severe versus mild to moderate blastomycosis.Setting: The Marshfield Clinic Health System in central and northern WisconsinParticipants: Patients with a diagnosis of blastomycosis prior to 2017 were contacted for enrollment in this study. A phone hotline was also set up to allow interested participants from outside the Marshfield Clinic Health System to request enrollment.Methods: SNP frequency was assessed for significant differences between the patient cohort and controls and between patients with severe versus mild to moderate blastomycosis. We also tested the effect of Blastomyces species identified in clinical isolates on disease symptoms and severity.Results: No significant differences were found in SNP frequency between cases and controls or between those with severe or mild to moderate blastomycosis. We did detect significant differences in symptom frequency and disease severity by Blastomyces species.Conclusions: Our study did not identify any genetic risk factors for blastomycosis. Instead, the species of Blastomyces causing the infection had a significant effect on disease severity.

Epistaxis and Facial Swelling Due to Nasal Blastomycosis in a Cat.

A 5 yr old castrated male domestic longhair was examined because of left-sided facial swelling and epistaxis. Head computed tomography with contrast identified a mass within the left nasal cavity and multifocal regions of nasal bone osteolysis. Histopathology of nasal mass biopsies and cytology of the facial swelling revealed pyogranulomatous inflammation due to Blastomyces dermatitidis. The cat experienced resolution of clinical signs following 8 mo of treatment with itraconazole. Although rare, clinicians should include blastomycosis on the differential diagnoses list of infectious causes for feline nasal disease if within an endemic area.

In vitro manogepix susceptibility testing of South African Emergomyces africanus, Emergomyces pasteurianus, and Blastomyces emzantsi clinical isolates.

We performed in vitro antifungal susceptibility testing of manogepix against the yeast phase of 78 Emergomyces africanus, 2 Emergomyces pasteurianus, and 5 Blastomyces emzantsi isolates using a reference broth microdilution method following Clinical and Laboratory Standards Institute recommendations. All three pathogens had low minimum inhibitory concentrations ranging from <0.0005 to 0.008 mg/L. Manogepix should be investigated in animal models and potentially in future human clinical trials for endemic mycoses.

Structural basis of Blastomyces Endoglucanase-2 adjuvancy in anti-fungal and -viral immunity.

The development of safe subunit vaccines requires adjuvants that augment immunogenicity of non-replicating protein-based antigens. Current vaccines against infectious diseases preferentially induce protective antibodies driven by adjuvants such as alum. However, the contribution of antibody to host defense is limited for certain classes of infectious diseases such as fungi, whereas animal studies and clinical observations implicate cellular immunity as an essential component of the resolution of fungal pathogens. Here, we decipher the structural bases of a newly identified glycoprotein ligand of Dectin-2 with potent adjuvancy, Blastomyces endoglucanase-2 (Bl-Eng2). We also pinpoint the developmental steps of antigen-specific CD4+ and CD8+ T responses augmented by Bl-Eng2 including expansion, differentiation and tissue residency. Dectin-2 ligation led to successful systemic and mucosal vaccination against invasive fungal infection and Influenza A infection, respectively. O-linked glycans on Bl-Eng2 applied at the skin and respiratory mucosa greatly augment vaccine subunit- induced protective immunity against lethal influenza and fungal pulmonary challenge.

First Japanese case of disseminated blastomycosis imported from North America: A case report.

Blastomycosis is a fungal infectious disease that can occur in both immunocompromised and immunocompetent populations endemic in North America, with no previous reports in Japan. A 26-year-old Japanese female patient with no relevant medical history presented intermittent left back pain and an abnormal shadow in the left upper lung field eight months ago at a local clinic. She was referred to our hospital for further evaluation and treatment. The patient currently lives in Japan, but until two years ago had spent several years in New York, Vermont and California. Chest computed tomography revealed a 30 mm mass with a cavity in the left pulmonary apex. The specimens obtained by transbronchial biopsy showed periodic acid-Schiff stain (PAS)-positive and Grocott-positive yeast-like fungi scattered among the granulomas, with no malignant findings, and the initial pathology did not lead to a definitive diagnosis. She was empirically started on fluconazole because of onset of multiple subcutaneous abscesses and was referred to the Medical Mycology Research Center. Although antibody tests could not diagnose the disease, blastomycosis was suspected based on the pathology of the skin and lung tissue at the Medical Mycology Research Center, and Blastomyces dermatitidis was identified by ITS analysis of the rRNA region. Her symptoms and CT findings gradually improved with fluconazole. We reported the first Japanese case of blastomycosis with pulmonary and cutaneous involvement in Japan. As the number of overseas travelers is expected to continue increasing, we would like to emphasize the importance of travel history interviews and information of blastomycosis.

Does metabolite matter? Defining target itraconazole and hydroxy-itraconazole serum concentrations for blastomycosis.

BACKGROUND: Itraconazole is the recommended first-line treatment for mild-to-moderate blastomycosis and consolidation treatment of moderate-to-severe disease. Itraconazole is metabolised into three metabolites, including an active metabolite hydroxy-itraconazole. Literature provides little evidence indicating whether therapeutic drug monitoring targets should be based on itraconazole parent compound alone or a sum of itraconazole and hydroxy-itraconazole serum concentrations. OBJECTIVES: This study aims to compare clinical outcomes and adverse drug events (ADEs) of combined itraconazole and hydroxy-itraconazole concentrations versus itraconazole parent compound alone in patients with blastomycosis. PATIENTS/METHODS: This study was a retrospective cohort review of patients ≥18 years with probable or proven Blastomyces infection who received itraconazole with at least one documented serum itraconazole concentration. The primary outcome was rate of partial or complete treatment response across three patient groups: (1) Itraconazole parent compound >1.0 mcg/ml (parent), (2) parent compound <1.0 mcg/ml, but a combined itraconazole and hydroxy-itraconazole >1.0 mcg/ml (combined) and (3) failure to achieve a combined or parent concentration >1.0 mcg/ml (subtherapeutic) for >75% of the duration of itraconazole therapy. RESULTS: A total of 80 patients were included (parent = 32, combined = 36, subtherapeutic = 12). No statistically significant difference was observed for rate of partial or complete treatment response (97% parent vs 94% combined, p = .99). Significantly higher mortality due to blastomycosis was observed in patients in the subtherapeutic group (0% parent vs 3% combined vs 25% subtherapeutic, p = .01). CONCLUSIONS: This study supports an itraconazole therapeutic target combining itraconazole and hydroxy-itraconazole >1.0 mcg/ml for blastomycosis treatment.

Discovery of highly reactive self-splicing group II introns within the mitochondrial genomes of human pathogenic fungi.

Fungal pathogens represent an expanding global health threat for which treatment options are limited. Self-splicing group II introns have emerged as promising drug targets, but their development has been limited by a lack of information on their distribution and architecture in pathogenic fungi. To meet this challenge, we developed a bioinformatic workflow for scanning sequence data to identify unique RNA structural signatures within group II introns. Using this approach, we discovered a set of ubiquitous introns within thermally dimorphic fungi (genera of Blastomyces, Coccidioides and Histoplasma). These introns are the most biochemically reactive group II introns ever reported, and they self-splice rapidly under near-physiological conditions without protein cofactors. Moreover, we demonstrated the small molecule targetability of these introns by showing that they can be inhibited by the FDA-approved drug mitoxantrone in vitro. Taken together, our results highlight the utility of structure-based informatic searches for identifying riboregulatory elements in pathogens, revealing a striking diversity of reactive self-splicing introns with great promise as antifungal drug targets.

Scrotal abscess as an unusual presentation of blastomycosis.

Blastomyces dermatitidis is an environmental fungus endemic to parts of Eastern North America that notably causes pulmonary infection in humans and other animals with the potential for extrapulmonary spread, particularly in immunocompromised hosts. However, it rarely presents with genitourinary (GU) tract involvement. Herein, we present a unique case of a 37-year-old immunocompetent male with genitourinary blastomycosis with the initial presentation of a scrotal abscess.

Disseminated blastomycosis with cutaneous involvement in a 57-year-old woman: a case report and review of management.

Blastomycosis is an infectious disease produced by the fungal organisms, Blastomyces dermatiditis and Blastomyces gilchristi. We present a 57-year-old woman with pulmonary blastomycosis and secondary cutaneous involvement. Her diagnosis was facilitated by dermatology consultation after approximately one year of delay. In endemic areas including Canada and the USA, individuals are at risk for blastomycosis when non-motile fungal spores are inhaled, thus producing pulmonary disease. The organism may disseminate over time, affecting a variety of extrapulmonary organ systems including the skin. In endemic regions of blastomycosis, this important cutaneous manifestation of disease should be considered with a high index of suspicion as to avoid delayed resolution and adverse outcomes.

UTILITY OF URINE ANTIGEN TESTING FOR DIAGNOSIS OF BLASTOMYCOSIS IN NONDOMESTIC FELIDS.

Blastomycosis caused by the fungus Blastomyces dermatitidis has been reported to cause disease in numerous species of nondomestic felids. Diagnosis of blastomycosis in domestic species often relies on the combination of clinical signs, radiographic findings, and commercial urinary antigen testing. In this report, the sensitivity, specificity, and positive and negative predictive values for urine blastomyces antigen testing for use in nondomestic felids were examined and compared with findings on postmortem examination. The study showed a sensitivity of 100%, specificity of 91.86%, positive predictive value of 50%, and negative predictive value of 100% for urine antigen testing. Furthermore, radiographic and hematologic findings were compared with those of animals diagnosed with blastomycosis. Radiographic evidence consistent with blastomycosis was found in those animals diagnosed via urine antigen testing, but no significant differences in plasma biochemistry parameters between diseased and nondiseased animals were found. This study provides evidence that a positive blastomycosis antigenuria test result should be combined with other diagnostic methods to confirm the presence of infection with B. dermatitidis, whereas a negative antigenuria test result is 100% effective in predicting the absence of disease.

Molecular Epidemiology of Blastomyces gilchristii Clusters, Minnesota, USA.

We characterized 2 clusters of blastomycosis cases in Minnesota, USA, using whole-genome sequencing and single-nucleotide polymorphism analyses. Blastomyces gilchristii was confirmed as the cause of infection. Genomic analyses corresponded with epidemiologic findings for cases of B. gilchristii infections, demonstrating the utility of genomic methods for future blastomycosis outbreak investigations.

Risk factors of severe blastomycosis and comparison of diagnosis and outcomes between immunocompetent and immunocompromised patients.

BACKGROUND: Blastomycosis is an endemic fungal infection that causes pulmonary and systemic disease. It can occur irrespective of the patient's immune status. The risk factors associated with the severity of the disease are not well studied. METHODS: This is a retrospective study of patients admitted with blastomycosis at the University of Kentucky Hospital from 2004 to 2019. Logistic regression was used to identify variables associated with severe blastomycosis. RESULTS: A total of 76 patients were identified; 22 (28.9%) had at least one immunosuppressive condition. Pulmonary blastomycosis was reported in 49/76 (65%) of the patients and disseminated infection in 27/76 (35.5%). All diagnostic tests were not significantly different in diagnostic results in immunocompromised vs immunocompetent patients. Cultures and histopathology were positive in 56/61 (91.8%) and 54/63 (85.7%) respectively. Blastomyces or Histoplasma antigen test was positive in 13/17 (76.4%) in immunocompromised patients compared to 26/42 (61.9%) in immunocompetent patients. Immunocompromised patients were more likely to be admitted to the hospital and ICU compared to immunocompetent patients. In the multivariate analysis, pulmonary multilobar disease (RR 5.68; 95% CI 2.13-15.15), obesity (RR 2.39; 95% CI 1.26-4.51), diabetes mellitus (RR 3.50; 95% CI 1.38-8.90) and immunosuppression (RR 2.28; 95% CI 1.14-4.56) were significant independent risk factors for severe blastomycosis. Inpatient mortality proportion was higher in immunocompromised patients but not statistically significant. CONCLUSION: Pulmonary multilobar disease, obesity, diabetes mellitus and immunosuppression were risk factors associated with severe blastomycosis. Immunocompromised patients required more frequent hospitalisations compared to immunocompetent patients.

Imaging findings of pulmonary blastomycosis in pediatric patients.

Blastomycosis is caused by Blastomyces dermatitidis, a thermally dimorphic fungus that lives in the form of spores in the soil in North America. The main mode of transmission is through the inhalation of these spores. Despite the importance of knowing the imaging characteristics of blastomycosis given the suggested high rates of dissemination in symptomatic children, a paucity of literature focuses on the imaging patterns of blastomycosis in the pediatric population. In this review, we describe the main imaging findings of pediatric pulmonary blastomycosis and briefly review extrapulmonary manifestations of the disease. Familiarity with these imaging manifestations is important to aid in rapid diagnosis.

Blastomycosis in Africa and the Middle East: A Comprehensive Review of Reported Cases and Reanalysis of Historical Isolates Based on Molecular Data.

BACKGROUND: Blastomycosis has been reported from countries in Africa and the Middle East, but a decades-long debate has persisted regarding whether this is the same disease known in North America and caused by Blastomyces dermatitidis and Blastomyces gilchristii. METHODS: We reviewed published cases of human and veterinary blastomycosis from Africa and the Middle East. We abstracted epidemiological and clinical features of cases, including sites of disease, diagnosis, management, outcomes, and, where available, genetic and antigenic typing of case isolates. In addition, we sequenced nucleic acids from 9 clinical isolates from Africa deposited in global collections as B. dermatitidis; for 5, we sequenced the internal transcribed spacer regions, and for the other 4 we sequenced the whole genomes. RESULTS: We identified 172 unique human patients with blastomycosis, including 159 patients from 25 African countries and 12 patients from 5 Middle Eastern countries, and also identified 7 reports of veterinary blastomycosis. In humans, cutaneous disease predominated (n = 100/137, 73%), followed by pulmonary (n = 73/129, 57%) and osteoarticular involvement (n = 61/128, 48%). Unusual direct microscopy/histopathological presentations included short hyphal fragments in tissues (n = 23/129, 18%). There were 34 genotyped case isolates that comprised 4 species: Blastomyces percursus (n = 22, 65%), from 8 countries throughout all regions; Blastomyces emzantsi (n = 9, 26%), from South Africa; B. dermatitidis (n = 1, 3%), from the Democratic Republic of Congo; and B. gilchristii (n = 2, 6%), from South Africa and Zimbabwe. CONCLUSIONS: Blastomycosis occurs throughout Africa and the Middle East and is caused predominantly by B. percursus and, at least in South Africa, B. emzantsi, resulting in distinct clinical and pathological patterns of disease.

Clinical Manifestations and Outcomes in Immunocompetent and Immunocompromised Patients With Blastomycosis.

BACKGROUND: Blastomyces is a dimorphic fungus that infects persons with or without underlying immunocompromise. To date, no study has compared the clinical features and outcomes of blastomycosis between immunocompromised and immunocompetent persons. METHODS: A retrospective study of adult patients with proven blastomycosis from 2004-2016 was conducted at the University of Wisconsin. Epidemiology, clinical features, and outcomes were analyzed among solid-organ transplantation (SOT) recipients, persons with non-SOT immunocompromise (non-SOT IC), and persons with no immunocompromise (NIC). RESULTS: A total of 106 cases met the inclusion criteria including 74 NIC, 19 SOT, and 13 non-SOT IC (malignancy, HIV/AIDS, idiopathic CD4+ lymphopenia). The majority of patients (61.3%) had at least 1 epidemiologic risk factor for acquisition of Blastomyces. Pneumonia was the most common manifestation in all groups; however, immunocompromised patients had higher rates of acute pulmonary disease (P = .03), more severe infection (P = .007), respiratory failure (P = .010), and increased mortality (P = .02). Receipt of SOT primarily accounted for increased severity, respiratory failure, and mortality in immunosuppressed patients. SOT recipients had an 18-fold higher annual incidence of blastomycosis than the general population. The rate of disseminated blastomycosis was similar among NIC, SOT, and non-SOT IC. Relapse rates were low (5.3-7.7%). CONCLUSIONS: Immunosuppression had implications regarding the acuity, severity, and respiratory failure. The rate of dissemination was similar across the immunologic spectrum, which is in sharp contrast to other endemic fungi. This suggests that pathogen-related factors have a greater influence on dissemination for blastomycosis than immune defense.

Changing Patterns of Disease Severity in Blastomyces dermatitidis Infection, Quebec, Canada.

This retrospective multicenter cohort study assessed temporal changes in the severity and mortality rate of blastomycosis in Quebec, Canada, and identified risk factors for death in patients with blastomycosis in 1988-2016. The primary outcome was 90-day all-cause deaths. Among 185 patients, 122 (66%) needed hospitalization and 30 (16%) died. We noted increases in the proportion of severe cases, in age at diagnosis and in the proportion of diabetic and immunocompromised patients over time. Independent risk factors for death were age (adjusted odds ratio [aOR] 1.04, 95% CI 1.00-1.07), immunosuppression (aOR 4.2, 95% CI 1.5-11.6), and involvement of >2 lung lobes (aOR 5.3, 95% CI 1.9-14.3). There was no association between the Blastomyces genotype group and all-cause mortality. The proportion of severe cases of blastomycosis has increased in Quebec over the past 30 years, partially explained by the higher number of immunosuppressed patients.

Development of a Duplex Real-Time PCR Assay for the Differentiation of Blastomyces dermatitidis and Blastomyces gilchristii and a Retrospective Analysis of Culture and Primary Specimens from Blastomycosis Cases from New York (2005 to 2019).

Blastomycosis due to Blastomyces dermatitidis and Blastomyces gilchristii is a significant cause of respiratory mycoses in North America with occasional reported outbreaks. We developed a highly sensitive, specific, and reproducible TaqMan duplex real-time PCR assay for the differentiation of B. dermatitidis and B. gilchristii The new assay permitted retrospective analysis of Blastomyces cultures (2005 to 2019) and primary clinical specimens from blastomycosis cases (2013 to 2019) from New York patients. We identified B. dermatitidis as the predominant pathogen in 38 cases of blastomycosis, while B. gilchristii was a minor pathogen involved in five cases; these findings expand understanding of blastomycosis in New York. The duplex real-time PCR assay could be implemented in reference and public health laboratories to further understand the ecology and epidemiology of blastomycosis due to B. dermatitidis and B. gilchristii.