Pleural empyema by Parvimonas micra in an immunocompetent patient: a case report

We present the case of a young immunocompetent patient, with a history of pulmonary tuberculosis, who attended the hospital with a subacute clinical picture of persistent fever, weight loss, dyspnea and abolition of vesicular murmur. Chest CT scan showed an extensive empyema in the left hemithorax. Samples were taken for detection of common germs. Then, a chest drainage tube was placed and antibiotic therapy started. The MALDI-TOF MS test identified Parvimonas micra, an anaerobic bacterium, commensal to the oral flora, associated with severe periodontitis, but rarely reported in cases of pleural empyema, especially in immunocompetent patients. Gingivitis and pericoronaritis of the third molar were diagnosed during oral evaluation. The patient progressed favorably. Parvimonas micra should be considered as a possible etiological agent in cases of subacute or chronic pleural empyema, in addition to mycobacteria. Tests such as MALDI-TOF MS or 16S rRNA sequencing, chest tube placement, empirical antibiotic coverage and an adequate oral evaluation should be considered in these cases.