First evidence of human infection by the kinetoplastid flagellate Dimastigella trypaniformis in a patient with urinary tract infection

Objectives: We report a unique case of an 88-year-old man presenting with symptoms consistent with a urinary tract infection, whose diagnostic evaluation led to the identification of a previously unrecognized motile flagellated protozoan. This case highlights the importance of considering emerging parasitic agents in cases of hematuria and complex urinary tract infections and underscores the role of molecular diagnostics in identifying atypical and rare pathogens. Design: This is a case report describing the clinical presentation, laboratory findings, and molecular identification of an unusual kinetoplastid organism in a patient's urine. The case is contextualized within the broader and expanding clinical spectrum of human trypanosomatid infections, emphasizing the significance of molecular techniques in detecting emerging and potentially pathogenic organisms. Methods/Results: Urine microscopy revealed the presence of a motile flagellated protozoan, prompting further investigation. Molecular identification using PCR and sequencing confirmed the organism as Dimastigella trypaniformis, a free-living kinetoplastid from the Rhynchomonadidae family. Previously, D. trypaniformis had only been reported in soil samples from Scotland and termite gut contents in Australia and Germany, with no known associations with vertebrate hosts. This case represents the first potential documented instance of D. trypaniformis in human urine. Conclusions: The identification of D. trypaniformis in a clinical specimen expands the spectrum of potential urinary pathogens and raises questions about its clinical significance and pathogenic potential. This report underscores the need for heightened awareness of rare and emerging parasitic infections, particularly in patients with atypical presentations. It also highlights the crucial role of molecular diagnostics in identifying novel organisms and guiding appropriate clinical management.