Anti-Protozoal Enema Treatment for Blastocystis hominis and Dientamoeba fragilis: Does Volume Matter?

Abstract

Introduction: Blastocystis hominis (Bh) and Dientamoeba fragilis (Df) are single-celled protozoans, becoming recognised as enteric pathogens associated with IBS-like symptoms including abdominal pain, bloating, constipation or diarrhoea and fatigue. Due to high failure rates with both oral mono and combination anti-protozoal therapies, we developed and tested a triple combination therapy via rectal enema administered over two days to determine eradication rate of Bh and Df and reduction of symptoms. Methods: The combination therapy compared 2 low volume (LV, 90 ml) versus 2 high volume (HV, 300ml) enemas. Patients with Bh and/or Df were treated either with LV or HV for two days using drug combinations of furazolidone 0.9g, secnidazole 3.6g and nitazoxanide 3.0g. In case of allergy the culprit drug was replaced by paromomycin 4.5g. Stool microscopy and Polymerase chain reaction technique were used for parasite detection. Symptom scores were recorded pre- and post-treatment (1 and 6 weeks). An unpaired T-TEST was used to compare the differences. Results: Twenty eight patients (n=18, F) who failed previous therapies (˜80%) and diagnosed with Bh (n=16), Df (n=7) or both Bh+Df (n=5) were treated with LV (n=13) or HV (n=15) rectal enemas using anti-parasitic drug combinations. Higher eradication was achieved in HV (13/15; 87%) compared to LV (7/13; 54%) (p=0.03) (Table 1). Regardless of the enema volume, symptoms significantly improved after treatment (Figure 1). No adverse events were reported in either cohort.116_A Figure 1. Anit-protozoal enema treatment for eradication of parasitesConclusion: Use of HV triple anti-protozoal therapy achieved a higher success rate in eliminating Bh and Df parasites. This may be due to the ability to access larger surface area of the colon with HV rectal enema, even though the concentrations of each drug per ml were reduced to 1/3 in comparison to LV. The treatment alleviates the symptoms associated with these enteric pathogens without detectable side effects.116_B Figure 2. Pre- and post- treatment symptoms between HV and LV rectal enema treatment for 28 patients with Blastocystis hominis and/or Dientamoeba fragilis infections. w: weeks; PT: post treatment; HV: High volume; LV: Low volume116_C Figure 3. Pre-and post-treatment symptoms between HV and LV rectal enema treatment for 28 patients with Blastocystis hominis and/or Dientamoeba fragilis infections. w: weeks; PT: post treatment; HV: High volume; LV: Low volume