LAUSR

Background Olsenella uli is anaerobic or microaerophilic bacteria, commonly found in oral cavity or gastrointestinal tract, which has not been reported to be associated with lower respiratory tract infection. Herein, we report the first case of Olsenella uli infection in the lung. Case presentation A 70-year-old male farmer with no history of other respiratory tract diseases developed a cough with bloody sputum three times a day without obvious causes or other concomitant symptoms. After a period of treatment with empirical antibiotic, his condition did not improve. The computed tomography (CT) and lung biopsy results indicated bilateral pneumonia, and Olsenella uli was identified by micromorphology, sequence analysis and mass spectrometry analysis recovered from sputum. Ceftazidime, a third generation cephalosporin was used for the treatment, and the patient recovered after 10 days. Conclusions Our report suggests a causative role of gingival bacteria in the pathogenesis of pneumonia, thus early diagnosis and prompt antibiotic therapy may play a role in the treatment of Olsenella uli induced pneumonia.