Study sugar substitute the cause of increased serious diarrhea

Sugar substitute promotes the spread of dangerous diarrhea

In recent years, infections with the intestinal bacterium Clostridium difficile have increased dramatically worldwide. In particular, in the hospital infections, the pathogen plays a role, but also in the general population, an increasing frequency of infections is observed. Scientists have now presented a surprising explanation for the increase in the corresponding infections. Thus, the sugar substitute trehalose could play a key role in the spread of particularly aggressive strains of the bacterium Clostridium difficile.

The research team headed by Professor Robert Britton of Baylor College of Medicine (USA) has linked the increasing number and severity of Clostridium difficile infections to trehalose in his recent study. "C. Difficile infections have always been a problem in hospitals, but over the past 15 years they have become the leading cause of hospital-acquired infections in developed countries, "said Professor Britton. The sugar substitute could have a significant share of this. The researchers published their study results in the journal "Nature".

The supposedly healthier sugar alternative trehalose promotes the spread of severe Clostridium difficile infections. (Image: Kateryna_Kon / fotolia.com)

Severe diarrhea and life-threatening colitis

The bacteria of the genus Clostridium difficile cause in humans a worst case life-threatening inflammation of the colon and severe diarrhea. "Patients aged 65 years and over are at particular risk, and most infections occur in people who have received medical care and antibiotics," the researchers report. In the United States, Clostridium difficile infections are a leading cause of death from infectious diseases, with nearly half a million infections and 29,000 estimated deaths in 2015, according to the Center for Disease Control and Prevention (CDC) according to the statement from Baylor College of Medicine.

Two bacterial lines have become increasingly common

The scientists were able to say that especially the "C. difficile lines RT027 and RT078 have recently become dominant around the world. "Although these lines have existed in humans for years without causing major outbreaks; and in the 1980s they were not epidemic or hypervirulent. "But after the year 2000, they began to dominate and cause big outbreaks," said the study's lead author. James Collins. The researchers therefore wondered why these lines could become such a health risk.

Bacteria can grow even at low trehalose concentration

The scientists first analyzed the food sources of the two C. difficile lines and discovered that they can grow even with low intake of the sugar substitute trehalose. The bacterial lines have been about a 1000 times lower concentration of trehalose to grow, compared with the other bacteria of the same genus, write the researchers. However, this does not explain why the infections lead to more severe symptoms than before. According to the researchers, the increased toxicity of the bacteria is responsible here, because it also increases when the sugar substitute trehalose is added.

Increased mortality in the mouse model

In the mouse model, the scientists checked their assumptions. They administered a diet with or without trehalose to mice colonized with a strain of C. difficile RT027 strain. "What the mice ate affected the virulence of the infection and the mortality was higher in the trehalose-consuming group," Dr. Collins. The increased disease severity in the presence of trehalose can not be explained by a higher number of bacteria, but is due to the increase in toxicity at RT027.

Increasing number of outbreaks since approval of trehalose

According to the researchers, the findings gained are also reflected in the increasing number of Clostridium difficile infections since around 15 years ago. "In 2000, trehalose was approved as a food additive in the US for a range of foods, from sushi and vegetables to ice cream, and about three years later reports of outbreaks began to increase with these lines," explains Professor Britton.

Unexpected consequences of the sugar alternative

While other factors may also have contributed to the increased C. difficile outbreaks, "but we believe trehalose is an important trigger"; Britton continued. Above all, it is important to realize that what was once considered to be a perfectly safe sugar alternative can have unexpected consequences. In particular, the effect of trehalose in the diet in patients in hospitals with RT027 and RT078 outbreaks must now be further investigated. (Fp)