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Clinical pilot study: efficacy of triple antibiotic therapy in Blastocystis positive irritable bowel syndrome
Robyn Nagel1, Helle Bielefeldt-Ohmann2, Rebecca Traub3
1School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia ; Toowoomba Gastroenterology Clinic, Suite 105 Medici Medical Centre, 15 Scott Street, Toowoomba 4350, Queensland, Australia.
Background:
Blastocystis species are common human enteric parasites. Carriage has been linked to Irritable Bowel Syndrome (IBS). Treatment of Blastocystis spp. with antimicrobials is problematic and insensitive diagnostic methods and re-infection complicate assessment of eradication. We investigated whether triple antibiotic therapy comprising diloxanide furoate, trimethoprim/sulfamethoxazole and secnidazole (TAB) given to diarrhoea-predominant IBS (D-IBS) patients positive for Blastocystis would achieve eradication.
Methods:
In a longitudinal, prospective case study 10 D-IBS Blastocystis-positive patients took 14 days of diloxanide furoate 500 mg thrice daily, trimethoprim/sulfamethoxazole 160/80 mg twice daily and secnidazole 400 mg thrice daily. Faecal specimens were collected at baseline, day 15 and 4 weeks after completion of TAB. Specimens were analysed using faecal smear, culture and polymerase chain reaction (PCR) of the 16 SSU rRNA. Patients kept a concurrent clinical diary.
Results:
Six (60%) patients cleared Blastocystis spp. after TAB, including three who had failed previous therapy. Subtypes detected were ST3 (60%), ST4 (40%), ST1 (20%) and ST7, 8 (10%); four patients had mixed ST infections. Serum immunoglobulin A (IgA) levels were low in 40% of patients. Higher rates of Blastocystis clearance were observed in patients symptomatic for less than a year (Mann-Whitney, p = 0.032, 95% confidence) with no associations found with age, previous antibiotic therapy, faecal parasite load, ST, IgA level or clinical improvement.
Conclusions:
Clearance of Blastocystis spp. was achieved with TAB in 60% of D-IBS patients, an improvement over conventional monotherapy. Higher clearance rates are needed to facilitate investigation of the relevance of this parasite in clinically heterogenous IBS.
Insights
Triple antibiotic therapy (TAB) eradicated Blastocystis species in 60% of diarrhea-predominant Irritable Bowel Syndrome (D-IBS) patients. This approach shows promise for treating Blastocystis infections linked to IBS symptoms.
Area of Science:
- Medical Parasitology
- Gastroenterology
- Infectious Diseases
Background:
- Blastocystis species are prevalent human enteric parasites.
- Blastocystis carriage is associated with Irritable Bowel Syndrome (IBS).
- Challenges exist in treating Blastocystis infections and assessing eradication due to diagnostic limitations and reinfection.
Purpose of the Study:
- To evaluate the efficacy of a triple antibiotic therapy (TAB) for eradicating Blastocystis species in patients with diarrhea-predominant IBS (D-IBS).
Main Methods:
- A prospective case study involving 10 D-IBS patients positive for Blastocystis.
- Patients received 14 days of a triple antibiotic therapy (diloxanide furoate, trimethoprim/sulfamethoxazole, and secnidazole).
- Faecal samples were analyzed using smear, culture, and PCR at baseline, post-treatment, and follow-up; patients maintained clinical diaries.
Main Results:
- Sixty percent (60%) of patients achieved Blastocystis eradication with TAB, including those with prior treatment failures.
- Subtypes detected included ST3, ST4, ST1, and ST7/8, with several patients having mixed infections.
- Higher clearance rates were observed in patients symptomatic for less than one year.
Conclusions:
- Triple antibiotic therapy (TAB) achieved a 60% clearance rate of Blastocystis in D-IBS patients, surpassing conventional monotherapy.
- Improved clearance rates are necessary to further investigate the role of Blastocystis in diverse IBS presentations.
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