A rare case of pleural effusion due to Prevotella dentalis.

Prevotella dentalis is a Gram-negative anaerobic rod involved in various human diseases, especially oral infections. We report a rare case of a pleural effusion due to this microorganism in an elderly patient. An 88-year-old man with chronic respiratory disease presented with a left pleural effusion for more than 1 month. Culture of drained pleural fluid resulted in isolation of P. dentalis. Resistance to penicillin and moxifloxacin was documented. Treatment with drainage and clindamycin was established, but the patient developed cognitive impairment and died after a worsening of his general condition.