Diagnostic value of metagenomic next-generation sequencing in atypical brucellosis: a case report.

Background: Brucellosis with atypical presentations, such as submandibular abscess without fever, is frequently misdiagnosed. Methods: Metagenomic next-generation sequencing (mNGS) was applied to pus samples from a 47-year-old female with a treatment-refractory submandibular abscess and a history of livestock exposure; results were confirmed serologically. Results: Within 48 h, mNGS identified Brucella suis-representing, to our knowledge, the first reported afebrile submandibular infection caused by this pathogen. Targeted therapy with doxycycline and rifamycin led to symptom resolution within 6 days. Conclusion: This case highlights that mNGS, combined with a thorough epidemiological history, can resolve diagnostic dilemmas in atypical brucellosis, guide precise treatment, and mitigate antibiotic misuse.