[Pleural trichomoniasis due to trichomonas tenax].

Thoracic infections due to Trichomonas species often go unrecognised as they are seldom described in the literature. We describe a case that, to our knowledge, is the first reported case of empyema caused by this organism. A 59 year old man with metastatic adenocarcinoma of the lung developed a right pyopneumothorax following treatment with corticosteroids and radiotherapy. The pleural fluid was purulent and fetid, and contained large numbers of Trichomonas tenax amongst a mixed bacterial flora. Pleural drainage and antibiotic therapy with metronidazole, ciprofloxacin and gentalline were instituted immediately, but the patient died 4 days later. Trichomonas tenax is part of the normal oral floral and may on occasions colonize the airways. It can thus become involved during aspiration pneumonia or cause pleural infection following the rupture of a pulmonary abscess. Such infection tends to be associated with concurrent respiratory pathology or with immunodepression. The significance Trichomonas tenax when found in the airways is unclear and their pathogenic role is discussed.