Two-day enema antibiotic therapy for parasite eradication and resolution of symptoms

World J Gastroenterol. 2020 Jul 14;26(26):3792-3799. doi: 10.3748/wjg.v26.i26.3792.


Background: Blastocystis hominis (B. hominis) and Dientamoeba fragilis (D. fragilis) are two protozoan parasites of human bowel that are found throughout the world. There is still debate about the pathogenicity of these protozoans, despite them being commonly associated with gastrointestinal symptoms and can cause health issue in both children and adults. These parasites are usually transmitted through faecal-oral contact particularly under poor hygiene conditions or food/water contamination. Once a person is infected, the parasites live in the large intestine and are passed in the faeces.

Aim: To investigate the effect of triple antibiotic therapy using enema infusion in the treatment of B. hominis and D. fragilis infections.

Methods: This retrospective longitudinal study was conducted in a single medical centre, which included fifty-four patients (≥ 18 years) who were positive for D. fragilis, B. hominis or both between 2017 and 2018. The treatment consisted of triple antibiotics that were infused over two consecutive days through rectal enema. Faecal samples were collected from participants pre- and post-treatment and were tested for parasites using microscopy and polymerase chain reaction. Patients' symptoms were recorded prior and after the treatment as well as patient demographic data.

Results: Patients (n = 54), were either positive for B. hominis (37%), D. fragilis (35%) or both (28%). All patients completed the two-day treatment and no serious adverse effect was reported. The most common side effect experienced by the patients during the treatment was urine discolouration which was cleared by six weeks of follow-up. Common symptoms reported prior to treatment were diarrhoea, abdominal pain, constipation and fatigue. Other symptoms included abdominal discomfort, dizziness and blood in the stool. Eighty-nine percent of patients completed a final stool test post-treatment. At six weeks post-treatment, 79% of patients cleared the parasites from their faeces. Symptoms such as abdominal discomfort, dizziness and blood in the stool decreased significantly at both seven days and six weeks post-treatment (P < 0.040). The enema retention time, bowel preparation, previous antibiotic treatment or previous gastrointestinal problems had no significant effect on parasite eradication.

Conclusion: Overall, eradication of parasites and improvement of clinical outcomes were observed in treated patients, showing the efficacy of this combination to eradicate the parasites and provide positive clinical outcome.

Keywords: Antibiotics; Blastocystis hominis; Dientamoeba fragilis; Parasitic infection; Rectal enema route; Triple therapy.

MeSH terms

  • Adult
  • Animals
  • Anti-Bacterial Agents* / administration & dosage
  • Child
  • Enema*
  • Feces
  • Female
  • Humans
  • Longitudinal Studies
  • Male
  • Parasites*
  • Parasitic Diseases* / therapy
  • Retrospective Studies


  • Anti-Bacterial Agents