Pulmonary infection by Lophomonas spp. and Aspergillus spp. in a B-cell acute lymphocytic leukemia patient from Chile

The flagellated protozoan Lophomonas spp. is a commensal microorganism found in the intestinal tracts of cockroaches, termites, mites, and certain birds. It is the causative agent of a rare infection in humans called lophomoniasis, primarily affecting the lungs and mainly immunocompromised individuals. This parasitosis is transmitted to humans by air or through ingestion of the cystic forms of the parasite. We describe the case of a 50-year-old patient treated at a tertiary hospital in southern Chile with a history of B-cell acute lymphocytic leukemia. Radiological findings, along with increased levels of inflammatory parameters and galactomannan antigen in serum and Bronchoaveolar Lavage (BAL) raised the suspicion of a pulmonary infection. Microscopic study of BAL revealed oval to pyriform cells with mobile flagella at the anterior end, which were identified as Lophomonas spp. trophozoites, which based on EORTC/MSG criteria were associated with diagnosis of a probable pulmonary aspergillosis. Lophomoniasis was treated with metronidazole (500 mg IV every 8 h) for 14 days and pulmonary aspergillosis required a combination of fluconazole, voriconazole, anidulafungin, liposomal amphotericin B and isavuconazole. The patient responded favorably and was discharged after 95 days of hospitalization. This case highlights the importance of recognizing lophomoniasis as a parasitic infection in respiratory samples from immunocompromised patients who present pulmonary symptoms, especially those who do not respond satisfactorily to conventional antimicrobial treatments. Further research is needed to understand the various sources of Lophomonas spp. infection and develop infection prevention strategies particularly for high-risk patients.