Could a Widely Used Food Additive Be Contributing to Epidemic C. difficile?
Trehalose, a widely used dietary sugar, has been linked to the growing incidence and severity of healthcare-associated outbreaks caused by Clostridium difficile, according to a study published in Nature.
Approved in 2000, trehalose, a food additive, is found in various foods such as sushi, chewing gum, baked goods, and ice cream. "[...] about three years later the reports of outbreaks with [C. difficile lineages RT027 and RT078] started to increase," stated corresponding author Dr. Robert Britton, Baylor College of Medicine, "Other factors may also contribute, but we think that trehalose is a key trigger."
To get a better understanding of what factors help RT027 and RT078 increase their virulence, the researchers looked at what sources of food these lineages preferred. The findings indicated that these 2 ribotypes were able to grow on trehalose sugar levels that were ~1,000 times lower than those required by other lineages. RT027 and RT078 "have acquired unique mechanisms to metabolize low concentrations of the disaccharide trehalose," explained Dr. James Collins, a postdoctoral associate, and lead author of the study.
The team then evaluated a mouse model of C. difficile infection to to associate the low levels of trehalose with more severe disease. After mice with the RT027 lineage of C. difficile were given a diet with or without low trehalose levels, the authors found that mortality rate was greater in the group consuming trehalose. Additional studies showed that the increased disease severity seen in the presence of trehalose was due to higher toxin production by RT027 and not due to the mice having more bacteria.
The team's studies demonstrate that trehalose affects the virulence of the infection, contributing to the predominance of C. difficile lineages. "An important contribution of this study is the realization that what we once considered a perfectly safe sugar for human consumption, can have unexpected consequences," said Dr. Collins. Additional studies are needed to investigate the effect of trehalose in the diets of hospitalized patients with RT027 and RT078 outbreaks.
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