Oct 24 11 7:19 PM

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No Advantage For Antibiotic Treatment Over Placebo In Blastocystis Hominis-Positive Children With Recurrent Abdominal Pain.


*Division of Gastroenterology and Nutrition, University Children's Hospital Zurich, Switzerland †Children's Research Centre (CRC), Zürich, Switzerland.



The aim of the study was to investigate if recurrent abdominal pain (RAP) in Blastocystis hominis (B. hominis)-positive children can be treated successfully with trimethoprim-sulfamethoxazole (TMP/SMX).


From October 2004 to December 2008 all patients referred to the Division of Gastroenterology and Nutrition of the University Children's Hospital Zurich because of RAP, and detection of B. hominis in stool samples as the only pathological finding after a standard work up, were offered to participate in the study. Patients were randomly assigned into two groups TMP/SMX or placebo was given for seven days in a double blind, placebo-controlled manner. Pain index (PI) was measured with a visual analogue scale. Two weeks after completion of treatment three stool samples were collected and patients were followed clinically. If B. hominis was still present, metronidazole was given for seven days.


40 patients were included, 37 finished the study (TMP/SMX n = 20, placebo n = 17). Mean PI declined from 7.1 to 3.6 for all patients, with a decrease from 6.9 to 4.1 in the TMP/SMX and 7.4 to 3.0 in the placebo group, irrespective of detection of B. hominis after treatment. There was no statistically significant difference in PI reduction between the two groups. Metronidazole treatment led to a further PI decline from 3.7 to 1.9. Eradication rate was 35% (TMP/SMX) and 44% (metronidazole), compared to spontaneous clearance of 29% in the placebo group.


There is no advantage for TPM/SMX over placebo in the treatment of RAP in B. hominis-positive children.