Randomised clinical trial of synbiotic therapy in elective surgical patients.

Gut 53(2):241-5.

Anderson AD, McNaught CE, Jain PK, MacFie J. 2004.

Summary and comments by Mary Ellen Sanders, Ph.D.

Probiotics have been shown in limited human and some animal studies to improve gut barrier function (i.e., decrease transit of bacteria across the intestinal barrier) and reduce inflammation. One of the hopes for probiotics is that they might be useful in institutional settings to reduce infections and complications from contaminating microbes. Anderson et al. (2004) tested this hypothesis in a double blind, randomized human trial using patients undergoing elective abdominal surgery. Patients were randomized into one of two groups. The synbiotic group received a probiotic [a capsule containing 10⁹ cfu each of Lactobacillus acidophilus La5, Bifidobacterium lactis Bb-12, Lactobacillus bulgaricus (strain not indicated) and Streptococcus thermophilus (strain not indicated) three times per day for a total daily dose of 1.2x10¹⁰ total probiotic organisms] and a prebiotic (16 g oligofructose powder dissolved in one cup of water twice daily). The placebo group received placebo capsules and sucrose powder. Treatment was administered prior to surgery for an average of 12 days, and postoperatively for 4-5 days.

The study did not identify any benefits to consuming the synbiotic preparation. There were no statistically significant differences in bacterial translocation (defined as a positive mesenteric lymph node or serosal scraping), gastric colonization, systemic inflammation (as measured by serum C-reactive protein, interleukin 6 and antiendotoxin core antibody), septic complications (as measured by presence of pathogens in normally sterile body tissues) or days of hospitalization. These negative results were consistent with a previous similar study using a different probiotic preparation, L. plantarum 299V.

Authors speculated that failure to show a benefit could have been due to:

• Unsuitable strains or dose, although the dose is similar to doses used successfully in other clinical evaluations
• Patient intolerance to the synbiotic preparation for the first 1-3 days post surgery
• Short duration of post-operative treatment (4 days in placebo group and 5 in synbiotic group)
• Not enough subjects in the study. The number of study subjects was determined assuming 15% translocation prevalence. However, overall prevalence of translocation in the study was only 6.6%.

Future research may define effective combinations of probiotic strains to improve morbidity in surgical patients. This study suggests that the tested synbiotic preparation was not useful in this application.