Pleural empyema due to polymicrobial Clostridioides difficile, Clostridium tertium and Robinsoniella peoriensis following C. difficile peritonitis.

We report a case of a male in his late-60s who presented with acute onset chest pain of one day duration and worsening dyspnea on exertion for more than one week, with chest radiograph notable for right-sided pleural effusion. Pleural fluid analysis revealed an exudative effusion and cultures from pleural fluid grew Clostridioides difficile, Clostridium tertium, and Robinsoniella peoriensis. His past medical history was significant for polymicrobial C. difficile and Escherichia coli peritonitis with a negative stool glutamate dehydrogenase assay. The patient was treated with six-week course of metronidazole. This is the first reported case of Robinsoniella peoriensis empyema and highlights the rarity of polymicrobial extra-intestinal anaerobic infection and the serious challenges in treatment due to the lack of established guidelines.