A case-controlled study of Dientamoeba fragilis infections in children

Abstract

Dientamoeba fragilis is a pathogenic protozoan parasite that is implicated as a cause of human diarrhoea. A case-controlled study was conducted to determine the clinical signs associated with D. fragilis infection in children presenting to a Sydney Hospital. Treatment options are also discussed. Stool specimens were collected from children aged 15 years or younger and analysed for the presence of D. fragilis. In total, 41 children were included in the study along with a control group. Laboratory diagnosis was performed by microscopy of permanently stained, fixed faecal smears and by real-time PCR. Gastrointestinal symptoms were present in 40/41 (98%) of these children with dientamoebiasis, with diarrhoea (71%) and abdominal pain (29%) the most common clinical signs. Chronic gastrointestinal symptoms were present in 2% of cases. The most common anti-microbial used for treatment was metronidazole (n=41), with complete resolution of symptoms and clearance of parasite occurring in 85% of cases. A treatment failure rate occurred in 15% of those treated with metronidazole. Follow-up treatment comprised of an additional course of metronidazole or iodoquinol was needed in order to achieve complete resolution of infection and symptoms in this group. This study demonstrates the pathogenic potential of D. fragilis in children and as such it is recommended that all laboratories must routinely test for this organism and treat if detected.

Enteric Protozoa in the Developed World: a Public Health Perspective

“…Infection may be acute or chronic and has been reported in both children and adults and both immunocompetent and immunosuppressed populations (26,127,361,389,392,444). The most common clinical symptoms include abdominal pain, persistent diarrhea, loss of appetite, weight loss, and flatulence (22,355,389,444). These symptoms are akin to those of irritable bowel syndrome (IBS), so D. fragilis should be considered in the differential diagnosis of IBS (399).…”

“…Various antimicrobial therapies have resulted in the successful clearance of D. fragilis and total resolution of gastrointestinal symptoms in infected patients (152,387,445). Paromomycin, secnidazole, iodoquinol, tetracycline, ornidazole, and metronidazole have been used successfully to treat D. fragilis infections (22,152,305,445). However, there is emerging evidence of treatment failures of metronidazole among D. fragilis isolates, suggesting the increased need for combination therapy for these protozoa (22,389).…”

“…Paromomycin, secnidazole, iodoquinol, tetracycline, ornidazole, and metronidazole have been used successfully to treat D. fragilis infections (22,152,305,445). However, there is emerging evidence of treatment failures of metronidazole among D. fragilis isolates, suggesting the increased need for combination therapy for these protozoa (22,389). Combination therapy has been effective in the complete eradication of the parasite and in resolution of symptoms (387,389).…”

Application of PCR-based methods for diagnosis of intestinal parasitic infections in the clinical laboratory

“…It is my intention that this paper will provide some guidance on answering these questions and overcoming hurdles to the introduction and adoption of molecular diagnostic methods in the clinical laboratory. (Jones et al 2008;Poirier et al 2011;) Cryptosporidium DNAJ-like protein, SSU rDNA, COWP (Verweij et al 2004;ten Hove et al 2007ten Hove et al , 2009Bruijnesteijn van Coppenraet et al 2009;Hadfield SJ et al 2011;Stark et al 2011;Stroup et al 2012;Liu et al 2013;Mejia et al 2013;Nazeer et al 2013) Cyclospora SSU rDNA, HSP70 (Varma et al 2003;Verweij JJ et al 2003;Blans et al 2005;Hussein et al 2007;Lalonde LF and Gajadhar AA, 2011;Shields et al 2013) D. fragilis SSU rDNA, 5.8S rDNA (Stark et al 2006(Stark et al , 2008(Stark et al , 2010Verweij et al 2007b;Bruijnesteijn van Coppenraet et al 2009;Banik et al 2011) E. histolytica SSU rDNA (Blessmann et al 2003;Verweij et al 2004;Qvarnstrom et al 2005;Visser et al 2006;Bruijnesteijn van Coppenraet et al 2009;ten Hove et al 2009;Othman et al 2010;Liu et al 2013) E. dispar (Verweij et al 2003a;Kebede et al 2004a, b;Calderaro A et al 2006;Visser et al 2006;Hamzah et al 2010;Liang et al 2010;Stensvold et al 2011;…”

Dientamoeba fragilis and chronic abdominal pain in children: a case-control study

“…Most researchers assume D. fragilis as a pathogen9 11 16 17 19 21 22 25 28–30 because many studies show that in the setting of D. fragilis infection, gastrointestinal symptoms often subside after antimicrobial eradication 11 14 22 24 30 31. On the other hand, some consider it a commensal organism27 because D. fragilis is frequently found in asymptomatic individuals 26 31.…”