The metagenomic next-generation sequencing in diagnosing central nervous system angiostrongyliasis: a case report

Diagnosis of human angiostrongyliasis in a case of hydrocephalus using next-generation sequencing: a case report and literature review

BACKGROUND

Angiostrongyliasis cantonensis is a severe yet rare parasitic infection caused by the larvae of Angiostrongylus cantonensis. The primary characteristic feature of this foodborne illness in humans is eosinophilic meningitis. Recently, there has been a gradual increase in reported cases globally. Due to the lack of typical clinical symptoms, signs, and specific laboratory tests, early diagnosis of this disease poses significant challenges. Failure to diagnose and treat this condition promptly can result in fatalities.

METHODS

We present the case of a 13-year-old male patient who initially presented with fever and headache. The patient was preliminarily diagnosed with bacterial meningitis and received treatment with antibacterial drugs. However, the patient's condition worsened, and he developed progressive consciousness disturbances. Eventually, metagenomic next-generation sequencing (mNGS) testing of cerebrospinal fluid samples indicated Angiostrongylus cantonensis infection. Following treatment with albendazole and prednisone, the patient made a full recovery. We include this case report as part of a literature review to emphasize the potential applications of mNGS in the early diagnosis of Angiostrongyliasis cantonensis.

CONCLUSION

mNGS technology plays a crucial role in the diagnosis of angiostrongyliasis cantonensis. As this technology continues to evolve and be applied, we believe it will play an increasingly important role in diagnosing, treating, and monitoring angiostrongyliasis cantonensis.

Angiostrongylus cantonensis induces energy imbalance and dyskinesia in mice by reducing the expression of melanin-concentrating hormone

BACKGROUND

Infection with Angiostrongylus cantonensis (AC) in humans or mice can lead to severe eosinophilic meningitis or encephalitis, resulting in various neurological impairments. Developing effective neuroprotective drugs to improve the quality of life in affected individuals is critical.

METHODS

We conducted a Gene Ontology enrichment analysis on microarray gene expression (GSE159486) in the brains of AC-infected mice. The expression levels of melanin-concentrating hormone (MCH) were confirmed through real-time quantitative PCR (RT-qPCR) and immunofluorescence. Metabolic parameters were assessed using indirect calorimetry, and mice's energy metabolism was evaluated via pathological hematoxylin and eosin (H&E) staining, serum biochemical assays, and immunohistochemistry. Behavioral tests assessed cognitive and motor functions. Western blotting was used to measure the expression of synapse-related proteins. Mice were supplemented with MCH via nasal administration.

RESULTS

Postinfection, a marked decrease in Pmch expression and the encoded MCH was observed. Infected mice exhibited significant weight loss, extensive consumption of sugar and white fat tissue, reduced movement distance, and decreased speed, compared with the control group. Notably, nasal administration of MCH countered the energy imbalance and dyskinesia caused by AC infection, enhancing survival rates. MCH treatment also increased the expression level of postsynaptic density protein 95 (PSD95) and microtubule-associated protein-2 (MAP2), as well as upregulated transcription level of B cell leukemia/lymphoma 2 (Bcl2) in the cortex.

CONCLUSIONS

Our findings suggest that MCH improves dyskinesia by reducing loss of synaptic proteins, indicating its potential as a therapeutic agent for AC infection.

[High-throughput sequencing for infectious disease diagnoses: Example of shotgun metagenomics in central nervous system infections]

The advent of high-throughput sequencing in clinical microbiology is opening the way to new diagnostic and prognostic approaches in infectious diseases. Detection, identification and characterisation of pathogenic microorganisms are essential steps in diagnosis and implementation of appropriate antimicrobial therapy. However, standard methods of microbiological diagnosis are failing in some cases. In addition, the emergence of new infections, facilitated by international travel and global warming, requires the implementation of innovative diagnostic methods. Among the different strategies used in clinical microbiology and reviewed in this article, shotgun metagenomics is the only technique that allows today a panpathogenic and unbiased detection of all microorganisms potentially responsible for an infectious disease, including those still unknown. The aims of this article are to present the different possible strategies of high-throughput sequencing used in the microbiological diagnosis of infectious diseases and to highlight the diagnostic contribution of shotgun metagenomics in the field of central nervous system infections.

High-throughput metagenomics analysis in early and precise diagnosis of eosinophilic meningoencephalitis complicated with respiratory failure: A case report

RATIONALE

Human infection with Angiostrongylus cantonensis is uncommon and has only been sporadically reported in the literature. Patients infected with A cantonensis usually have a delayed diagnosis and sometimes a poor prognosis.

PATIENT CONCERNS

A 70-year-old woman presented to the respiratory department with complaints of headache, chest pain, myalgia, fatigue, and anorexia for 7 days.

DIAGNOSES

Complete blood count showed eosinophilia. The serum was tested showing a positive finding of A cantonensis antibody. Cerebrospinal fluid was tested using high-throughput metagenomics analysis and 16 reads for A cantonensis were mapped. The patient was diagnosed with A cantonensis infection.

INTERVENTIONS

The patient received a 7-day course of albendazole and 4-day course of prednisone.

OUTCOMES

When discharged from the hospital, the patient still suffered from fatigue and poor memory. Aminotransferase levels were high due to albendazole's liver toxicity. In a post-discharge follow-up about 1 month later she had recovered completely both physically and mentally, and peripheral eosinophil count and aminotransferase levels were both normal.

LESSONS

Because the direct identification of parasites is difficult, high-throughput metagenomics analysis may provide a reliable alternative tool for the diagnoses of infection with A cantonensis. When albendazole is prescribed, caution must be taken with respect to its liver toxicity.

mNGS facilitates the accurate diagnosis and antibiotic treatment of suspicious critical CNS infection in real practice: A retrospective study

Whether metagenomic next-generation sequencing (mNGS) could benefit patients with suspected severe central nervous system (CNS) infection in terms of diagnosis and antibiotic treatment remains unknown. We retrospectively analyzed 79 patients with suspected CNS infection and undertook mNGS. The value of mNGS was investigated in terms of identification of pathogen and guidance for the adjustment of antibiotic treatment. The relationship between the time of initiating mNGS since onset and the Glasgow Outcome Scale (GOS) score after 90-day follow-up were analyzed. Fifty out of 79 cases with suspicious severe CNS infection were finally diagnosed. Despite previous routine laboratory tests, mNGS further promoted the accurate identification of pathogens in 23 cases (47.9%). The sensitivity, specificity, and accuracy of mNGS test in this study were 84.0, 79.3, and 82.3%, respectively. Furthermore, mNGS facilitated the adjustment of empirical antibiotic treatments in 38 cases (48.1%). The time of taking mNGS since onset had an insignificant weak positive correlation with GOS after 90-day follow-up (r = -0.73, P = 0.08). mNGS facilitated the accurate identification of pathogens in suspicious severe CNS infections and promoted the accurate antibiotic therapy even empirical antibiotics were administrated. It should be taken as early as possible to improve the clinical outcome of patients with suspicious severe CNS infection.

The application of metagenomic next-generation sequencing for Angiostrongylus eosinophilic meningitis in a pediatric patient: A case report

Background

Angiostrongylus eosinophilic meningitis (AEM) is a rare yet emerging disease caused by Angiostrongylus cantonensis infection. Its atypical symptoms may delay the diagnosis and cause fatal outcomes, especially in the early stages of infection and among children.

Case presentation

Here we reported the use of metagenomic next-generation sequencing (mNGS) to facilitate the diagnosis and treatment of an 8-year-old boy with severe A. cantonensis infection. The mNGS tests consistently identified the infection of A. cantonensis prior to the detection by the immunologic method and confirmed it as AEM. Owing to the multidisciplinary team (MDT)-administrated treatments and close disease monitoring based on regular clinical tests and sequential mNGS tests, the patients eventually fully recovered from severe infectious conditions.

Conclusion

This case demonstrated the advantages of mNGS for early diagnosis of AEM in pediatric patients, highlighting its application for pan-pathogen detection, as well as disease monitoring for severe A. cantonensis infection.

Epidemiological, clinical and laboratory aspects of Angiostrongylus cantonensis infection: an integrative review

This integrative literature review study analyzes the findings of the last 5 years of the parasite Angiostrongylus cantonensis. It is known that this nematode is found in the pulmonary arteries of rats, where it remains as a definitive host. From mice, the cycle spreads to animals, such as snails, which in contact with humans can trigger the disease. In humans, the parasite causes several neurological, abdominal manifestations and mainly meningitis. Based on the review of studies, its epidemiology shows worldwide distribution, although there are endemic cases for this parasite, such as asian countries. Laboratory findings generally showed altered CSF with turbidity, increased protein and eosinophilia, which generated meningeal signs in the patient, moreover MRI exams showed multiple alterations. Rare findings of the nematode in the eyeball, lung and signs of peritoneal inflammation were reported, which requires further studies to understand the whole pathophysiology. Finally, conservative treatment based on anthelmintics and anti-inflammatories brought good responses, although there are reports of deaths, which demonstrates the importance in the prevention and therapy of this disease.

Angiostrongilus cantonensis an Atypical Presenilin: Epitope Mapping, Characterization, and Development of an ELISA Peptide Assay for Specific Diagnostic of Angiostrongyliasis

Background: Angiostrongyliasis, the leading cause universal of eosinophilic meningitis, is an emergent disease due to Angiostrongylus cantonensis (rat lungworm) larvae, transmitted accidentally to humans. The diagnosis of human angiostrongyliasis is based on epidemiologic characteristics, clinical symptoms, medical history, and laboratory findings, particularly hypereosinophilia in blood and cerebrospinal fluid. Thus, the diagnosis is difficult and often confused with those produced by other parasitic diseases. Therefore, the development of a fast and specific diagnostic test for angiostrongyliasis is a challenge mainly due to the lack of specificity of the described tests, and therefore, the characterization of a new target is required. Material and Methods: Using bioinformatics tools, the putative presenilin (PS) protein C7BVX5-1 was characterized structurally and phylogenetically. A peptide microarray approach was employed to identify single and specific epitopes, and tetrameric epitope peptides were synthesized to evaluate their performance in an ELISA-peptide assay. Results: The data showed that the A. cantonensis PS protein presents nine transmembrane domains, the catalytic aspartyl domain [(XD (aa 241) and GLGD (aa 332–335)], between TM6 and TM7 and the absence of the PALP and other characteristics domains of the class A22 and homologous presenilin (PSH). These individualities make it an atypical sub-branch of the PS family, located in a separate subgroup along with the enzyme Haemogonchus contournus and separated from other worm subclasses. Twelve B-linear epitopes were identified by microarray of peptides and validated by ELISA using infected rat sera. In addition, their diagnostic performance was demonstrated by an ELISA-MAP4 peptide. Conclusions: Our data show that the putative AgPS is an atypical multi-pass transmembrane protein and indicate that the protein is an excellent immunological target with two (PsAg3 and PsAg9) A. costarisencis cross-reactive epitopes and eight (PsAg1, PsAg2, PsAg6, PsAg7, PsAg8, PsAg10, PsAg11, PsAg12) apparent unique A. cantonensis epitopes. These epitopes could be used in engineered receptacle proteins to develop a specific immunological diagnostic assay for angiostrongyliasis caused by A. cantonensis.

The Potential Role of Clinical Metagenomics in Infectious Diseases: Therapeutic Perspectives

Clinical metagenomics (CMg) is the process of sequencing nucleic acid of clinical samples to obtain clinically relevant information such as the identification of microorganisms and their susceptibility to antimicrobials. Over the last decades, sequencing and bioinformatic solutions supporting CMg have much evolved and an increasing number of case reports and series covering various infectious diseases have been published. Metagenomics is a new approach to infectious disease diagnosis that is currently being developed and is certainly one of the most promising for the coming years. However, most CMg studies are retrospective, and few address the potential impact CMg could have on patient management, including initiation, adaptation, or cessation of antimicrobials. In this narrative review, we have discussed the potential role of CMg in bacteriology, virology, mycology, and parasitology. Several reports and case-series confirm that CMg is an innovative tool with which one can (i) identify more microorganisms than with conventional methods in a single test, (ii) obtain results within hours, and (iii) tailor the antimicrobial regimen of patients. However, the cost-efficiency of CMg and its real impact on patient management are still to be determined.

Case Report: A Severe and Multi-Site Nocardia farcinica Infection Rapidly and Precisely Identified by Metagenomic Next-Generation Sequencing

Nocardia genus is an aerobic, gram-positive, and opportunistic pathogen, which mainly affects cell-mediated immunosuppressed patients. Early diagnosis and treatment greatly improve prognosis. However, the limitation of golden standard-bacterial culture exists. Here, we report a 61-year-old male with pneumonia, sepsis and intermuscular abscesses induced by Nocardia farcinica. Venous blood culture reported negative results. Former improper diagnosis and treatment did not improve his condition. With the assistant of metagenomic next-generation sequencing, the pathogen was identified as Nocardia farcinica. He was then applied with accurate treatment and had a remarkable clinical and radiological improvement.