Evaluation of Five Non-Culture-Based Methods for the Diagnosis of Meningeal Sporotrichosis

Extracutaneous sporotrichosis

SUMMARYSporotrichosis is a subacute-to-chronic infection endemic to tropical and subtropical regions. It usually involves subcutaneous tissue but can occasionally cause extracutaneous infections, especially in hyperendemic areas. Extracutaneous infections are classified based on the anatomic location of the lesion and the route of infection (primary or multifocal). The clinical forms are as follows: (i) pulmonary (primary or multifocal); (ii) osteoarticular (primary or multifocal); (iii) ocular (ocular adnexal lesions including eyelid lesions, conjunctivitis and dacryocystitis, and intraocular infections); (iv) central nervous system; and (v) mucosal (primary or disseminated). Multifocal clinical presentations are observed mainly in immunocompromised individuals. The diagnosis must be confirmed in the laboratory by mycological examination of the clinical samples. Itraconazole and amphotericin B are the most commonly used antifungal agents for treating pulmonary, osteoarticular, ocular, and mucosal forms. Treatment may include surgical excision of the initial lesions in pulmonary and osteoarticular forms. The treatment of neurological involvement is far from optimal and is associated with a high mortality rate despite long treatment periods.

Molecular diagnostics in cerebrospinal fluid for the diagnosis of central nervous system infections

SUMMARYCentral nervous system (CNS) infections can be caused by various pathogens, including bacteria, viruses, fungi, and parasites. Molecular diagnostic methods are pivotal for identifying the different causative pathogens of these infections in clinical settings. The efficacy and specificity of these methods can vary per pathogen involved, and in a substantial part of patients, no pathogen is identified in the cerebrospinal fluid (CSF). Over recent decades, various molecular methodologies have been developed and applied to patients with CNS infections. This review provides an overview of the accuracy of nucleic acid amplification methods in CSF for a diverse range of pathogens, examines the potential value of multiplex PCR panels, and explores the broad-range bacterial and fungal PCR/sequencing panels. In addition, it evaluates innovative molecular approaches to enhance the diagnosis of CNS infections.

Emerging Fungal Infections of the Central Nervous System in the Past Decade: A Literature Review

INTRODUCTION

Invasive fungal infections affecting the central nervous system (CNS) are a major health concern worldwide associated with high mortality rates. Their increased incidence is largely due to an increase in the vulnerable immunocompromised population, changing environmental factors, and development of more accurate diagnostic methods. The aim of this article is to identify fungal causes of CNS infections that are recently emerging or have the potential to become emerging pathogens in the near future, as well as their clinical characteristics, including: Candida auris, Trichosporon spp., Blastomyces spp., Sporothrix spp., Talaromyces marneffei, Lomentospora prolificans, and Scedosporium spp.

METHODS

A review of the literature in PubMed in the last ten years was conducted to identify central nervous system infections caused by each of these fungi.

RESULTS

The review identified 10 cases caused by C. auris, 5 cases by Trichosporon spp., 82 cases by Blastomyces spp., 36 cases by Sporothrix spp., 21 cases by T. marneffei, 22 cases by Lomentospora prolificans, and 42 cases by Scedosporium spp.

DISCUSSION

The exact burden of these diseases remains difficult to ascertain, but their apparent rise underscores the urgent need for improved diagnostic, treatment, and management strategies against CNS fungal pathogens to improve outcomes against these life-threatening infections.

Antibody Isotype and Subclass Responses in Human Patients With Different Clinical Presentations of Sporotrichosis

Sporotrichosis diagnosis involves a series of analyses, including culture and antibody detection in serum samples. Serologic methods may sometimes yield false-negative or false-positive results, leading to inaccurate diagnoses. This study assessed specific patient groups in which antibody detection of different isotypes and subclasses may lack sensitivity. An enzyme-linked immunosorbent assay (ELISA) with Sporothrix brasiliensis exoantigens was used to investigate IgM, IgG, IgG1, IgG2, IgG3, IgG4, IgA, IgA1 and IgA2 antibodies in human serum samples. Eighty serum samples from patients with different sporotrichosis clinical manifestations, including cutaneous forms with and without hypersensitivity manifestations, extracutaneous forms (bone, ocular, meningeal and pulmonary), disseminated cutaneous forms and disseminated forms in individuals living with HIV/AIDS, diabetics and alcoholics, were evaluated. The ELISA sensitivities in the detection of different antibodies ranged from 0.85 to 0.60 for the detection of IgG2 and IgG3, respectively. The antibodies with higher area under ROC curves were IgG2, IgG, IgA and IgA1. There were no significant differences in the immunological reactivity of the tested antibodies among different clinical forms of sporotrichosis. The data revealed a higher likelihood of a false-negative outcome in patients with lesions in the nasal mucosa regarding the detection of IgM and a lower likelihood in patients with lymphocutaneous sporotrichosis regarding the detection of IgG3. Patients with hypersensitivity manifestations had a 3.71 odds ratio to yield negative results in total IgG detection. In conclusion, we identified specific patient groups in which antibody detection may lack sensitivity, thus contributing to a better understanding of the diagnostic challenges associated with this condition.

Meningeal sporotrichosis in an immunocompetent host: A case report

A 78-year-old woman presented to hospital with altered mental status. Hyponatremia was diagnosed and treated. She maintained mental confusion despite normal sodium. No headache, fever or focal signs were present. CSF analysis showed chronic meningitis; MRI demonstrated basilar enhancement. She was empirically treated for tuberculosis, with no improvement. PCR for Sporothrix in the CSF was positive. After treatment with Amphotericin followed by oral itraconazole, she completely recovered her cognitive abilities. Follow-up CSF was normal. This report illustrates the need to consider sporotrichosis in the differential diagnosis of chronic meningitis in immunocompetent, and the importance of PCR as a diagnostic tool.

The present and future research agenda of sporotrichosis on the silver anniversary of zoonotic sporotrichosis in Rio de Janeiro, Brazil

Twenty-five years have passed since the initial observation of endemic zoonotic sporotrichosis in Rio de Janeiro, Brazil. Since then, this disease has spread throughout South America. Accompanying the emergence of this mycosis, some progress has been made, including the expansion of a research network in this field and higher visibility of sporotrichosis within government authorities and funding agencies. However, there are still some challenges to curbing the expansion of this disease in the coming years. These include the development of rapid and accurate diagnostic tests, new antifungal drugs, particularly for the treatment of extracutaneous manifestations of sporotrichosis, and more comprehensive care for cats with sporotrichosis. Including these actions in the sporotrichosis research agenda is required so as to change the development of this disease in the years to come.

Clinical characteristics, diagnosis, and treatment of central nervous system sporotrichosis: Systematic review and meta-analysis

BACKGROUND

The clinical features of central nervous system (CNS) sporotrichosis are derived from case reports and a limited series of cases. Our objective was to carry out a systematic review and meta-analysis of CNS sporotrichosis.

METHODS

We searched PubMed/MEDLINE, Embase, Scopus, and LILACS on 9 September 2023. Our inclusion criteria were documentation of Sporothrix and demonstrated CNS involvement. A metaproportion or metamean analysis was performed to estimate a summary proportion with 95% confidence intervals.

RESULTS

We included 52 cases of CNS sporotrichosis published from 1966 to 2023. Forty-six patients were male (88%, 95% CI: 77-95), and the mean age was 39 years (95% CI: 36-43). Close contact with cats was reported in 55% of cases (95% CI: 37-72). Thirty-two (61.5%) patients were from Brazil, 18 patients from the United State of America (34.6%). Only two Sporothrix species were reported: S. schenckii (26/41, 63%), and S. brasiliensis (15/41, 37%). The most common neurological symptom was headache. Meningitis was chronic in approximately 80% of cases. A significant majority of the patients were immunocompromised. HIV infection was the primary cause of immunosuppression (85%, 95% CI: 61-95). Overall mortality was 56% (22/39). The comparison of Kaplan-Meier survival curve showed a higher mortality with a statistically significant difference in immunosuppressed patients (p = .019).

CONCLUSION

CNS sporotrichosis represents a notable cause of chronic meningitis, especially in individuals living in the Americas with HIV infection and concurrent skin lesions.