Pneumonia, a pulmonary abscess, and an empyema caused by Parvimonas micra

Background: Pneumonia with an empyema caused by anaerobic bacteria is rare but can be life-threatening, especially in immunocompromised patients. Case presentation: A 67-year-old man with diabetes and hypertension who presented with pneumonia and pleural effusion and was unresponsive to initial broad-spectrum antibiotics is presented. Next-generation sequencing identified Parvimonas micra and other pathogens. Therefore, targeted therapy with levornidazole was initiated. The patient's condition improved significantly after this treatment. Conclusions: This case highlights the importance of considering anaerobic bacteria in immunocompromised patients and the utility of next-generation sequencing in identifying atypical pathogens.