Candida-reactive T cells for the diagnosis of invasive Candida infection of the lumbar vertebral spine

Malassezia restricta as an unexpected cause of infectious osteomyelitis diagnosed by metagenomic sequencing: a case report and literature review

BACKGROUND

Malassezia restricta, a lipophilic and lipodependent yeast belonging to the basidiomycetes group, is an opportunistic fungal pathogen associated with various skin diseases, including seborrheic dermatitis and dandruff. Typically, Malassezia infection in neonates manifests as fungemia or hematogenous dissemination to the bone or lungs. However, vertebral osteomyelitis caused by these fungi is rarely reported owing to non-specific clinical presentations and laboratory/imaging findings. The Pathogen Metagenomics Sequencing (PMseq) technique enables direct high-throughput sequencing of infected specimens, facilitating the rapid and accurate detection of all microorganisms in clinical samples through comprehensive reports.

CASE PRESENTATION

A 52-year-old male was admitted to our hospital on July 20, 2022 with a 3-month history of ambulatory difficulties and localized low back pain. Magnetic Resonance Imaging (MRI) examination of the spinal column revealed irregular bone destruction affecting the L2, L3, and L5 vertebral bodies. Additionally, low T1 and high T2 intensity lesions were observed at the intervertebral discs between L3 and L5. The presumptive diagnosis of tuberculous spondylitis was made based on the imaging findings, despite negative results in all mycobacterium tests. However, the patient exhibited no improvement after receiving regular anti-tuberculosis treatment for 3 months. Subsequent MRI revealed an expansive abnormal signal within the vertebral body, leading to progressive bone destruction. The absence of spinal tuberculosis or other infective microorganisms was confirmed through culture from blood and pathological tissue from the L4 vertebral body. Subsequently, PMseq was performed on the specimens, revealing M. restricta as the predominant pathogen with the highest relative abundance value. The pathological examination revealed the presence of fungal mycelium in the L4 vertebral body, with positive findings on periodic Schiff-methenamine and periodic acid-Schiff staining. The anti-tuberculosis treatment was discontinued, and an antifungal combination of fluconazole and voriconazole was administered. All symptoms were resolved after 7 consecutive months of treatment, and the patient was able to ambulate autonomously. Vertebral lesions were reduced on MRI during the 13-month follow-up.

CONCLUSIONS

M. restricta is not a commonly recognized pathogen associated with infectious vertebral osteomyelitis. However, PMseq can aid in diagnosis, timely treatment, and decision making for some non-specific infectious diseases.

Anti-fungal T cell responses in the lung and modulation by the gut-lung axis

The lung is a central organ for immune-environmental interactions ranging from tolerance against harmless substances to protection against pathogens, which are particularly sensitive to regulation by the intestinal microbiota. Airborne fungi, can cause variety of diseases, including allergies and inflammatory disorders, as well as life-threatening invasive infections. Remarkable differences exist between ubiquitous fungal species with regard to protective immune mechanisms. Recent data have surprisingly identified Aspergillus-specific regulatory T cells as an essential tolerance checkpoint and provided mechanistic insight for the loss of tolerance in the course of immune pathologies. Furthermore, pathogenic Th17 cells in Aspergillus-associated inflammatory disease seem to be induced by cross-reactivity to the intestinal commensal Candida albicans. Here we review and discuss what is known about fungus-specific T cell responses in the lung how they are modulated by the gut-lung axis and in particular discussing the modulation of adaptive immune responses by cross-reactivity to the microbiota.

ECMM CandiReg-A ready to use platform for outbreaks and epidemiological studies

BACKGROUND

Recent outbreaks of Candida auris further exemplify that invasive Candida infections are a substantial threat to patients and healthcare systems. Even short treatment delays are associated with higher mortality rates. Epidemiological shifts towards more resistant Candida spp. require careful surveillance.

OBJECTIVES

Triggered by the emergence of C auris and by increasing antifungal resistance rates the European Confederation of Medical Mycology developed an international Candida Registry (FungiScope™ CandiReg) to allow contemporary multinational surveillance.

METHODS

CandiReg serves as platform for international cooperation to enhance research regarding invasive Candida infections. CandiReg uses the General Data Protection Regulation compliant data platform ClinicalSurveys.net that holds the electronic case report forms (eCRF). Data entry is supported via an interactive macro created by the software that can be accessed via any Internet browser.

RESULTS

CandiReg provides an eCRF for invasive Candida infections that can be used for a variety of studies from cohort studies on attributable mortality to evaluations of guideline adherence, offering to the investigators of the 28 ECMM member countries the opportunity to document their cases of invasive Candida infection. CandiReg allows the monitoring of epidemiology of invasive Candida infections, including monitoring of multinational outbreaks. Here, we describe the structure and management of the CandiReg platform.

CONCLUSION

CandiReg supports the collection of clinical information and isolates to improve the knowledge on epidemiology and eventually to improve management of invasive Candida infections. CandiReg promotes international collaboration, improving the availability and quality of evidence on invasive Candida infection and contributes to improved patient management.

First Report of Candida auris Spondylodiscitis in Oman: A Rare Presentation

BACKGROUND

Candida auris is an emerging superbug which was recently discovered and has spread widely across the world. With a steady rise in incidence involving multisystems, this presents a unique challenge to caregivers.

CASE DESCRIPTION

A 50-year-old man with sickle cell disease, diabetes mellitus, and multiple surgeries presented with progressive low back pain radiating to bilateral limbs and intact neurology. Radiologic and laboratory investigations suggested spondylodiscitis with epidural collection, which was operated with posterior decompression and stabilization. The tissue analysis was reported as C. auris, which was accordingly treated with caspofungin. Magnetic resonance imaging at 4 months showed resolution of infection with return of inflammatory markers to normal.

CONCLUSIONS

C. auris appears to be an emerging superbug, which is hospital-acquired. All practitioners must be aware of its existence and presentation. Given the low incidence, high mortality, and no clear guidelines of management so far, formulation of any such strategies is complicated. Further studies and research are needed for this superbug.

Defining breakthrough invasive fungal infection-Position paper of the mycoses study group education and research consortium and the European Confederation of Medical Mycology

Breakthrough invasive fungal infections (IFIs) have emerged as a significant problem in patients receiving systemic antifungals; however, consensus criteria for defining breakthrough IFI are missing. This position paper establishes broadly applicable definitions of breakthrough IFI for clinical research. Representatives of the Mycoses Study Group Education and Research Consortium (MSG-ERC) and the European Confederation of Medical Mycology (ECMM) reviewed the relevant English literature for definitions applied and published through 2018. A draft proposal for definitions was developed and circulated to all members of the two organisations for comment and suggestions. The authors addressed comments received and circulated the updated document for approval. Breakthrough IFI was defined as any IFI occurring during exposure to an antifungal drug, including fungi outside the spectrum of activity of an antifungal. The time of breakthrough IFI was defined as the first attributable clinical sign or symptom, mycological finding or radiological feature. The period defining breakthrough IFI depends on pharmacokinetic properties and extends at least until one dosing interval after drug discontinuation. Persistent IFI describes IFI that is unchanged/stable since treatment initiation with ongoing need for antifungal therapy. It is distinct from refractory IFI, defined as progression of disease and therefore similar to non-response to treatment. Relapsed IFI occurs after treatment and is caused by the same pathogen at the same site, although dissemination can occur. These proposed definitions are intended to support the design of future clinical trials and epidemiological research in clinical mycology, with the ultimate goal of increasing the comparability of clinical trial results.

Mould-reactive T cells for the diagnosis of invasive mould infection-A prospective study

Invasive mould infections (IMI) in immunocompromised patients are difficult to diagnose. Early and targeted treatment is paramount, but minimally invasive tests reliably identifying pathogens are lacking. We previously showed that monitoring pathogen-specific CD4+T cells in peripheral blood using upregulation of induced CD154 positive lymphocytes can be used to diagnose acute IMI. Here, we validate our findings in an independent patient cohort. We stimulated peripheral blood cells from at-risk patients with Aspergillus spp. and Mucorales lysates and quantitated mould-reactive CD4/CD69/CD154 positive lymphocytes via flow cytometry. Mould-reactive lymphocytes were quantitated in 115 at-risk patients. In 38 (33%) patients, the test was not evaluable, mainly due to low T cell counts or non-reactive positive control. Test results were evaluable in 77 (67%) patients. Of these, four patients (5%) had proven IMI and elevated mould-reactive T cell signals. Of 73 (95%) patients without proven IMI, 59 (81%) had mould-reactive T cell signals within normal range. Fourteen (19%) patients without confirmed IMI showed elevated T cell signals and 11 of those received antifungal treatment. The mould-reactive lymphocyte assay identified presence of IMI with a sensitivity of 100% and specificity of 81%. The mould-reactive lymphocyte assay correctly identified all patients with proven IMI. Assay applicability is limited by low T cell counts during bone marrow suppression. The assay has the potential to support diagnosis of invasive mould infection to facilitate tailored treatment even when biopsies are contraindicated or cultures remain negative.

Candida-Reactive T Cells for the Diagnosis of Invasive Candida Infection-A Prospective Pilot Study

Background: Blood or tissue culture or histology prove invasive Candida infection, but long time to result, limited feasibility and sensitivity call for new approaches. In this pilot project, we describe the diagnostic potential of quantitating Candida-reactive, CD4/CD69/CD154 positive lymphocytes in blood of patients with invasive Candida infection.

Methods: We used flow cytometry quantitating Candida-reactive, CD4/CD69/CD154 positive lymphocytes from peripheral blood of patients with invasive Candida infection, from patients at risk and healthy volunteers as controls.

Results: Elevated levels of Candida-reactive lymphocytes were measured in 13 patients with proven invasive Candida infection and in one patient with probable hepatosplenic candidiasis. Results of three candidemia patients were uninterpretable due to autofluorescence of samples. Twelve of 13 patients had Candida identified to species level by conventional methods, and T cell reactivity correctly identified Candida species in 10 of 12 patients. Nine hematological high-risk patients and 14 healthy donors had no elevated Candida-reactive T cell counts.

Conclusions: This Candida-reactive lymphocyte assay correctly identified the majority of patients with invasive Candida infection and the respective species. Our assay has the potential to support diagnosis of invasive Candida infection to species level and to facilitate tailored treatment even when biopsies are contraindicated or cultures remain negative.

Host Genetic Signatures of Susceptibility to Fungal Disease

Our relative inability to predict the development of fungal disease and its clinical outcome raises fundamental questions about its actual pathogenesis. Several clinical risk factors are described to predispose to fungal disease, particularly in immunocompromised and severely ill patients. However, these alone do not entirely explain why, under comparable clinical conditions, only some patients develop infection. Recent clinical and epidemiological studies have reported an expanding number of monogenic defects and common polymorphisms associated with fungal disease. By directly implicating genetic variation in the functional regulation of immune mediators and interacting pathways, these studies have provided critical insights into the human immunobiology of fungal disease. Most of the common genetic defects reported were described or suggested to impair fungal recognition by the innate immune system. Here, we review common genetic variation in pattern recognition receptors and its impact on the immune response against the two major fungal pathogens Candida albicans and Aspergillus fumigatus. In addition, we discuss potential strategies and opportunities for the clinical translation of genetic information in the field of medical mycology. These approaches are expected to transfigure current clinical practice by unleashing an unprecedented ability to personalize prophylaxis, therapy and monitoring for fungal disease.