First reported Tannerella forsythia infection in a patient with extensive bronchiectasis: a case report

<i>Tannerella forsythia</i> infection was common in oral diseases but less reported in lung diseases. This report presents a patient with bronchiectasis who was infected by <i>Tannerella forsythia</i> and subsequently hospitalized with symptoms including fever, progressive cough, sputum production, and shortness of breath. A chest computed tomography (CT) scan revealed multiple bilateral pulmonary bronchiectasis with signs of infection. Metagenomic next-generation sequencing (mNGS) of the bronchoalveolar lavage fluid primarily detected <i>Tannerella forsythia</i>. Treatment with Piperacillin-tazobactam and ornidazole resulted in a favorable outcome. This case first reported a patient with extensive bronchiectasis infected by <i>Tannerella forsythia</i> and provided an effective treatment.