Summary

While probiotics are supposed to balance the intestinal flora, they do not always have the desired effect. A new study shows that they do not provide any protection against infectious complications in severe pancreatitis and may even make matters worse.

Introduction

Acute pancreatitis, which is a severe inflammation of the pancreas, is increasing at a rate of five percent per year in the United States and Europe. The condition can be very serious, for around a fifth of patients develop a complication called necrotizing pancreatitis, which has a 10-30 percent mortality rate. The underlying cause of necrotizing pancreatitis is infection of surrounding tissue and bacterial overgrowth in the small bowel. It was previously thought that antibiotic therapy might help avert this complication, but various trials have shown that this is not so.

Probiotics, which are mixtures of so-called 'friendly' bacteria are increasingly popular for their ability to promote digestive health and boost immunity. They are supposed to restore the balance of the intestinal flora which may be disturbed by disease or antibiotic treatment. Millions of healthy people swallow a probiotic drink every day, but what about the effect of probiotics on those who have a gastrointestinal disorder? Previous research has suggested that probiotics do reduce infectious complications among patients undergoing elective abdominal operations and those with acute pancreatitis. But the studies have been small and therefore doctors are not sure whether patients should be given probiotics or not. Researchers for the Dutch Acute Pancreatitis Group have carried out a larger, placebo-controlled study, to find if probiotics can play a useful role in improving the outcome in pancreatitis.

What was done

A group of 296 individuals admitted to hospital with a first episode of acute pancreatitis were enrolled in the study. Examination and lab tests suggested their condition was likely to progress and they were at risk of infectious complications. The researchers assigned 152 participants to infusion of a probiotic mixture twice a day for 28 days. The remaining patients received placebo infusions. Infectious complications, including necrotizing pancreatitis and pneumonia were recorded, along with the death rate.

What was found

Infectious complications occurred among 30 percent of the probiotics group and 28 percent of those in the placebo group. Sixteen percent in the probiotics group died, compared to six percent in the placebo group. Nine patients in the probiotics group developed a potentially fatal complication known as bowel ischemia, and eight of them died. None in the placebo group progressed to bowel ischemia.

What this means

The researchers admit they are a little surprised by these findings. They might have expected the probiotic preparation to prevent bacterial overgrowth in the small bowel and so ward off the infectious complications of acute pancreatitis. Instead, probiotics seem to slightly increase the chance of infection and, more worryingly, mortality. It is not clear why this should be, or whether some other mixture of probiotic bacteria might produce a more favorable outcome. Until further studies have been carried out, probiotic treatment must not be used in patients with acute pancreatitis. The study is a wake-up call - probiotics are not always helpful, or even benign.