Colonic amoebiasis and spirochetosis: Morphological, ultrastructural and microbiological evaluation

The present study reports on a prompt diagnosis of colonic amoebiasis with colonic spirochetosis by Brachyspira aalborgi and B. pilosicoli; such diagnosis allowed exclusion of other diseases and resolution of the case after specific treatment. A 37-year-old Italian man with a history of several months' mucosal diarrhea travelled to Greece, Romania and Tunisia. After his last trip he presented with an increase of up to 3-5 discharges daily, associated with bloody diarrhea, supporting the clinical suspect of inflammatory bowel disease. Colonoscopy revealed erosions from the cecum to the rectum, and ulcers both in the descending and sigmoid colon. Structures resembling amoebic trophozoites and sinusoidal microorganisms were observed in the colonic biopsies at histopathology and electron microscopy. Entamoeba histolytica DNA was detected by small-subunit rDNA polymerase chain reaction (PCR) from feces, rectal biopsies and isolated trophozoites. Spirochetes were identified from feces, colonic biopsies and cultures using a 16S rDNA restriction fragment length polymorphism-PCR specific for the detection of B. aalborgi and B. pilosicoli. After therapy, the patient was restored to health. The rapid identification of E. histolytica, B. aalborgi and B. pilosicoli using traditional and specific and sensitive molecular methods permitted an accurate diagnosis and a specific therapy. It is suggested that mixed infection by parasites and spirochetes might occur more frequently than expected: it would be of extreme interest and importance to intensify clinical findings, and one infection should not prompt the pathologist/clinician to stop looking.