Oral-Lung Connection: Prevotella Intermedia Identified In Lung Abscess

We report a challenging case demonstrating diagnostic complexity in pulmonary tuberculosis complicated by an initially misdiagnosed lung abscess without a typical air-fluid level. Metagenomic next-generation sequencing (mNGS) identified Prevotella intermedia, highlighting oral hygiene's critical but overlooked role in pulmonary infections. A 53-year-old woman presented with chronic cough and fatigue. Despite anti-tuberculosis treatment from June 2022 to August 2023, her right lower lung lesion progressively worsened on repeated CT scans. After repeated ineffective therapies, detailed patient history revealed chronic gingival inflammation lasting over five years with notable swelling and redness around her right lower canine and occlusal trauma due to edge-to-edge canine occlusion. Despite prolonged anti-tuberculosis regimens, only after targeted anaerobic antimicrobial therapy (cefotaxime, metronidazole) and periodontal interventions did the patient’s lung lesion significantly improve, ultimately resolving completely. This case underscores clinicians’ frequent neglect of dental examinations in persistent pulmonary conditions, especially atypical abscesses. Chronic gingivitis and occlusal trauma, often disregarded, can predispose to aspiration-induced lung abscesses. mNGS played a pivotal role by accurately identifying the causative pathogen, facilitating precise antimicrobial selection and highlighting the clinical relevance of maintaining oral hygiene in preventing systemic complications. Integrating oral and respiratory health assessments is essential, particularly in cases refractory to conventional treatments. This case demonstrates the diagnostic utility of mNGS for atypical pathogens and reinforces the importance of multidisciplinary care, combining dental management and tailored antibiotic therapy. These practices could substantially enhance patient outcomes in complex pulmonary infections originating from oral pathogens.