A probiotic available in Russia can eradicate small intestinal bacterial overgrowth (SIBO) in patients who also have irritable bowel syndrome (IBS), researchers have found.

The placebo-controlled study included IBS patients with or without SIBO. It found the bacterial combination of four strains of bacteria also significantly improved abdominal pain, stool frequency and stool consistency.

“These are impressive results, and I look forward to seeing a large study that duplicates these results—such a study would be conclusive,” said Mark Pimentel, MD, director of the GI Motility Program at Cedars-Sinai Medical Center, in Los Angeles.

Elena Polouektova, MD, a researcher at I.M. Sechenov First Moscow State Medical University, and her colleagues recruited 64 patients with ROME III–defined IBS to receive 28 days of either an oral placebo or 250 mg twice daily of Florasan-D. Florasan-D includes a combination of Bifidobacterium bifidum, Bifidobacterium longum, Bifidobacterium infantis and Lactobacillus rhamnosus.

Thirty-one patients had diarrhea-predominant IBS (IBS-D) and 33 had constipation-predominant IBS (IBS-C). The investigators measured abdominal pain using a visual analog scale (VAS) and used the Bristol Stool Chart to categorize stool consistency. They also documented bloating and flatulence.

Dr. Polouektova’s team conducted lactulose hydrogen breath testing to assess the presence of SIBO, which 21 patients with IBS-D and 19 with IBS-C had at study outset.

The findings revealed that IBS-D patients treated with the probiotic experienced statistically significant improvements in several measures at 28 days, compared with baseline. Specifically, average abdominal pain intensity decreased from 4 to 3 points on a VAS; flatulence improved from 7 to 4 points; the average number of bowel movements dropped from 14 to eight per week at 28 days; and stool consistency improved from type 6 to 4 on the Bristol Stool Chart (P<0.05 for all).

Placebo recipients with IBS-D only reported statistically significant improvements in abdominal pain, with average scores on the VAS dropping from 3.5 at baseline to 2.5 points at 28 days (P=0.028).

The IBS-C patients who received the probiotic also experienced statistically significant improvements in abdominal pain (average VAS score at baseline, 4 vs. 2 at 28 days), stool frequency (average, three vs. seven times per week) and stool consistency (average, type 2 vs. 3 on Bristol Stool Chart; P<0.05 for baseline vs. 28 days for all measures). Placebo recipients only reported improvements in abdominal pain intensity, with a drop in average VAS scores from 4 to 3 at 28 days (P=0.028).

According to the lactulose breath test results, all patients in both the IBS-D and IBS-C groups who had SIBO at baseline experienced complete resolution of SIBO with treatment. None of the patients with SIBO at baseline who received a placebo experienced a change in their status, the investigators reported.

Dr. Pimentel said one feature of the study that strengthens the findings was the authors’ use of lactulose breath testing, which is an objective measure of SIBO status. A weakness, he said, was that the interventions were not necessarily administered in a double-blind fashion.

“I also think it would also have been useful to know whether there was a statistical correlation between SIBO eradication and symptom improvements,” Dr. Pimentel added.

The findings were presented at the 2015 Gut Microbiota for Health World Summit in Barcelona, Spain (abstract 15). The investigators could not be reached for comment.

—David Wild