Metagenomic next-generation sequencing may assist diagnosis of cat-scratch disease

Clinical Characteristics and Visual Outcomes of Cat Scratch Disease

PURPOSE

To describe the clinical presentation, ocular complications, treatment, and visual outcomes in a series of 17 patients from New Zealand with neuroretinitis secondary to Bartonella henselae.

METHODS

Retrospective cross-sectional single-center study from 2001 to 2024. Data was extracted from a clinical database of all patients treated for B. henselae over the past 23 years. Statistical analysis was performed using IBM SPSS Statistics ver. 26.0.

RESULTS

Seventeen patients (19 eyes) were included with 11 (65%) being female. The mean age at presentation was 28.3 ± 12.3 years (range, 13-60 years). The mean presenting visual acuity (Early Treatment Diabetic Retinopathy Study testing) was 50 ± 23 (range, 4-90). The mean final visual acuity was 78 ± 12 (range, 45-90). Eleven patients (65%) had cats or kittens at home, with only one (6%) recounting a history of being scratched. Eight patients (47%) demonstrated the characteristic macular star at presentation, with all eventually developing macular star within a mean of 6 days. Four patients (24%) had macular oedema, three (18%) had vasculitis, two (12%) had uveitis, two (12%) had disc granuloma, and one (6%) had multifocal chorioretinitis. Six patients (35%) were treated with rifampicin and doxycycline, one (6%) with rifampicin and azithromycin, two (12%) with doxycycline only, two (12%) with co-trimoxazole monotherapy, and one patient (6%), who was breast-feeding, was treated with erythromycin. Four patients (24%) did not have receive any treatment.

CONCLUSIONS

The characteristic macular star is not always manifest at initial presentation for patients with neuroretinitis secondary to B. henselae, nor is there always a preceding history of cat exposure. Not all patients require treatment to have a good visual outcome, and the immune status of the patient is important.

Neuroretinitis: a comprehensive review on aetiologies, clinical manifestations, and treatment options

Neuroretinitis connotes a descriptive clinical entity of optic disc oedema in association with macular exudates in a star configuration. Accordingly, it does not indicate a specific aetiology, although cat scratch disease caused by Bartonella henselae is the most common cause. Historically, the recognition of neuroretinitis dates to the early 20th century with the eventual understanding that the optic disc is the primary target of disease with secondary macular involvement. Neuroretinitis can be broadly divided into four categories: infectious, inflammatory, autoimmune and mimickers. The intention of this article is to review the various aetiologies of neuroretinitis with a focus on the etiopathogenesis, clinical manifestations, and management of B. henselae associated neuroretinitis and recurrent idiopathic neuroretinitis.

Cat scratch disease in children with nocturnal fever: A case report

BACKGROUND

Cat scratch disease (CSD) is the most common human infection caused by Bartonella henselae (B. henselae). The main manifestation is self-limited lymphadenopathy that primarily affects adolescents, and typically resolves without treatment within 2-4 months. However, individuals with compromised immune systems or immunodeficiency require specific antibacterial therapy following diagnosis. Due to its low incidence, nonspecific clinical manifestations, and diagnostic limitations, this condition often poses challenges for clinicians in terms of missed diagnoses and misdiagnoses.

CASE SUMMARY

The child was ultimately diagnosed with CSD. The primary manifestations included nocturnal fever, enlargement of lymph nodes in the neck, axilla and groin, and suspected brucellosis; however, both brucellosis tests conducted during the course of the illness yielded negative results. Bone marrow cytology indicated stimulated proliferation. Lymph node biopsy indicated hyperplasia of lymphoid tissue in the cervical lymph nodes (right), with combined immunohistochemical findings indicating reactive hyperplasia. Immunohistochemical analysis revealed CD20 B (+), CD3 T (+), BCL-6 (+), and BCL-2 (-). CD21 FDC networks were present and Ki67 expression in the germinal center was ~80%. Blood next-generation sequencing indicated B. henselae sequence number was 3. Serological test results demonstrated positive antibody response to B. henselae IgG (+), B. henselae IgM (+), Bartonella quintana (B. quintana) IgG (-) and B. quintana IgM (-), and the final diagnosis was CSD.

CONCLUSION

In patients presenting with fever at night and swollen lymph nodes of unknown origin, CSD should be considered.

A case report and literature review: Mycobacterium leprae infection diagnosed by metagenomic next-generation sequencing of cerebrospinal fluid

BACKGROUND

Leprosy is a chronic infectious disease caused by Mycobacterium leprae (M. leprae) that is responsible for deformities and irreversible peripheral nerve damage and has a broad spectrum of clinical and serological manifestations. Leprosy primarily affects the peripheral nerves and rarely presents with central nervous system involvement. Diagnosing leprosy can still be difficult in some cases, especially when the infection involves uncommon clinical manifestations and extracutaneous sites. Delayed diagnosis and treatment of leprosy may lead to irreversible damage and death.

CASE PRESENTATION

We report a case of a 30-year-old female presenting with "repeated high fever with symptoms of headache for 14 days". On the day of admission, physical signs of lost eyebrows and scattered red induration patches all over her body were observed. The patient's diagnosis was based on the clinical characteristics using a combination of metagenomic next-generation sequencing (mNGS) of cerebrospinal fluid (CSF) and slit-skin smear. After confirming Listeria meningitis and multibacillary leprosy with erythema nodosum leprosum (ENL), a type 2 reaction, she was treated with ampicillin sodium, dapsone, rifampicin, clofazimine, methylprednisolone, and thalidomide. At the 1-year follow-up, the frequency and severity of headaches have significantly decreased and a good clinical response with improved skin lesions was found.

CONCLUSION

This case highlights the importance of considering leprosy, which is a rare and underrecognized disease, in the differential diagnosis of skin rashes with rheumatic manifestations, even in areas where the disease is not endemic, and physicians should be alerted about the possibility of central nervous system infections. In addition, mNGS can be used as a complementary diagnostic tool to traditional diagnostic methods to enhance the diagnostic accuracy of leprosy.

Application of Next-Generation Sequencing (NGS) Techniques for Selected Companion Animals

Next-Generation Sequencing (NGS) techniques have revolutionized veterinary medicine for cats and dogs, offering insights across various domains. In veterinary parasitology, NGS enables comprehensive profiling of parasite populations, aiding in understanding transmission dynamics and drug resistance mechanisms. In infectious diseases, NGS facilitates rapid pathogen identification, characterization of virulence factors, and tracking of outbreaks. Moreover, NGS sheds light on metabolic processes by elucidating gene expression patterns and metabolic pathways, essential for diagnosing metabolic disorders and designing tailored treatments. In autoimmune diseases, NGS helps identify genetic predispositions and molecular mechanisms underlying immune dysregulation. Veterinary oncology benefits from NGS through personalized tumor profiling, mutation analysis, and identification of therapeutic targets, fostering precision medicine approaches. Additionally, NGS plays a pivotal role in veterinary genetics, unraveling the genetic basis of inherited diseases and facilitating breeding programs for healthier animals. Physiological investigations leverage NGS to explore complex biological systems, unraveling gene-environment interactions and molecular pathways governing health and disease. Application of NGS in treatment planning enhances precision and efficacy by enabling personalized therapeutic strategies tailored to individual animals and their diseases, ultimately advancing veterinary care for companion animals.

Unmasking Bartonella henselae infection in the shadows of long COVID thanks to clinical metagenomics

The diagnosis of long COVID often relies on symptoms post-COVID-19, occasionally lacking biological evidence. This case study illustrates how investigating long COVID uncovered an underlying bartonellosis through clinical metagenomics. Following mild COVID-19, a 26-year-old woman experienced persistent symptoms during 5 months, including axillary adenopathy. Pathological examination, 16 S rRNA PCR, and clinical metagenomic analysis were done on an adenopathy biopsy. The latter revealed Bartonella henselae DNA and RNA. Treatment with clarithromycin improved symptoms. This case underscores the relevance of clinical metagenomics in diagnosing hidden infections. Post-COVID symptoms warrant thorough investigation, and bartonellosis should be considered in polyadenopathy cases, regardless of a recent history of cat or flea exposures.

Application of metagenomic next-generation sequencing in the diagnosis of Bartonella neuroretinitis: a case report and literature review

BACKGROUND

Cat-scratch disease (CSD) is caused by Bartonella henselae infection. In atypical cases of CSD, pathogen determination is challenging. We report a case of Bartonella neuroretinitis with neither a clear history of scratches nor typical general symptoms. The diagnosis was made using metagenomic next-generation sequencing (mNGS), a high-throughput sequencing technology.

CASE PRESENTATION

A female patient presented to the ophthalmologist with complaint of blurred vision in her right eye. Although with history of raising a cat, she reported no clear history of scratches or typical general symptoms, except a fever of unknown origin which resolved spontaneously. The best corrected visual acuity (BCVA) of the right eye was count fingers. Fundus examination showed optic disc oedema, macular exudates and inferior exudative retinal detachment. Laboratory examination results showed increased value of serum C-reactive protein and erythrocyte sedimentation rate. Ocular involvement of toxoplasmosis, syphilis and tuberculosis were excluded. To identify the possible causative pathogen of the disease, mNGS of aqueous humour sample was performed and 521 reads of B. henselae were identified. Serological test results further showed a positive immunoglobulin G (IgG) titre of 1:64. Taking the contact history, clinical manifestations, mNGS and serological results into consideration, the diagnosis of Bartonella neuroretinitis (ocular CSD) was made. After appropriate treatment, the BCVA of the right eye improved to 20/25 in the last follow-up. Fundus examination showed a normal optic disc and macula, and the exudates had reduced.

CONCLUSION

mNGS, a fast and unbiased method, can be used to detect B. henselae (if present) in intraocular fluid samples.; however, the results should be interpreted together with the clinical symptoms and other auxiliary test results.

Genome Analysis of ST1 Bartonella henselae, a Zoonotic Pathogen Causing Endocarditis in an Elderly Patient in China

Infective endocarditis (IE) is a rare disease but with high associated mortality. Currently, the mainstays of diagnosis are still echocardiography and blood cultures. Here, we reported a case of infective endocarditis with negative blood cultures, and blood and aortic valve tissue metagenomic next-generation sequencing (mNGS) results suggested Bartonella henselae. In addition, we obtained the whole genomic sequence of B. henselae ZJBH strain. To our knowledge, this is the first report of B. henselae genomic analysis isolated from clinic in China. Furthermore, we described the whole genome sequencing (WGS) data incorporating all B. henselae from diverse sources worldwide and shed light on underlying risk of B. henselae transmitted between cats and humans.