Urinary infection due to Balantioides coli: a rare accidental zoonotic disease in an addicted and diabetic young female in Iran

BACKGROUND: Balantiosis, a rare zoonotic infection resulting in dysentery, is caused by the large ciliated protozoan parasite Balantioides coli. Humans acquire this organism via the faecal–oral route. Very rarely, extraintestinal infections can occur in the urinary tract system. There are very few case reports of urinary balantiosis in humans. CASE PRESENTATION: Here, an interesting case of urinary balantiosis in a 35-year-old addicted woman with multiple health problems including spontaneous abortion and diabetes is reported. Her midstream urine sample, collected while all sterile precautions were being taken, demonstrated B. coli along with Trichomonas vaginalis and bacteria. B. coli was identified by its characteristic morphology and rapid rotary motility in the urinary tract, which is an abnormal site for invasion by this parasite. CONCLUSION: To the best of our knowledge, this is only the eighth case described in literature in which B. coli was detected in urine sediment; it is reported for its rarity and for future reference.