Association of altered gut microbiota composition with chronic urticaria.

Background: An altered gut microbiota composition has recently been linked to some types of allergies.

Objective: To compare the relative amounts of Akkermansia muciniphila, Clostridium leptum, Faecalibacterium prausnitzii, and Enterobacteriaceae as members of gut microbiota among patients with chronic urticaria (CU) and healthy controls.

Methods: A total of 20 patients with CU and 20 healthy individuals matched by age and sex participated in the study. Fresh fecal samples were collected, and DNA extracted from stool samples was analyzed by real-time polymerase chain reaction for the qualitative and quantitative assays of the so-called bacteria.

Results: The frequencies of A muciniphila, C leptum, and F prausnitzii in healthy controls' stool samples were significantly more than those of patients with CU (P < .001, P < .01, and P < .05, respectively), whereas the Enterobacteriaceae family was detected in all patients and healthy controls' stool samples. The relative amounts of A muciniphila in healthy control positive samples were significantly higher than those of samples from patients with CU (P < .001). Furthermore, there was a corresponding increase of relative amounts of C leptum and F prausnitzii in healthy control positive samples compared with those of patients with CU (P = .09 and P = .08, respectively). The mean of the relative amounts of Enterobacteriaceae family in the stool samples from patients with CU was more than that of healthy controls; however, the difference was nearly significant (P = .12).

Conclusion: The results reveal a change of frequency and relative amounts of A muciniphila, C leptum, and F prausnitzii in patients with CU compared with healthy controls. This is the first study, to our knowledge, to show the change of microbiota composition in patients with CU.