How to Cultivate Clostridium difficile Infections

The emergence of more frequent and virulent Clostridium difficile infections (CDIs) has generally been attributed to antibiotic usage.  A recent study (J Collins et al Nature 2018; 553, 291–4.  doi:10.1038/nature25178) suggests that changes in our diet are a contributing factor as well.

From Abstract:

Here we show that two epidemic ribotypes (RT027 and RT078) have acquired unique mechanisms to metabolize low concentrations of the disaccharide trehalose. RT027 strains contain a single point mutation in the trehalose repressor that increases the sensitivity of this ribotype to trehalose by more than 500-fold. Furthermore, dietary trehalose increases the virulence of a RT027 strain in a mouse model of infection. RT078 strains acquired a cluster of four genes involved in trehalose metabolism, including a PTS permease that is both necessary and sufficient for growth on low concentrations of trehalose. We propose that the implementation of trehalose as a food additive into the human diet, shortly before the emergence of these two epidemic lineages, helped select for their emergence and contributed to hypervirulence.

From GI & Hepatology News: Food additive makes C difficile more virulent: “Prior to 2000, trehalose was limited by a relatively high cost of production.”  However, with innovations in production, trehalose concentrations in food increased, particularly in ice cream, pasta, and ground beef; “concentration in food skyrocketed form around 2% to 11.25%.”  In addition, the FDA in 2000 noted that trehalose as “generally recognized as safe.”

My take“On the basis of these observations, we propose that the widespread adoption and use of the disaccharide trehalose in the human diet has played a significant role in the emergence of these epidemic and hypervirulent strains,” Dr. Collins and his colleagues wrote in Nature.

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