Objective: Ileal pouch anal anastomosis (IPAA) is the preferred method for restorative surgery in patients with ulcerative colitis who have to undergo proctocolectomy. The most common complication is pouchitis and several studies have pointed to the microbiota of the pouch as being a risk factor. The aim of this study was to follow the development of the bacterial microbiota in pouches during the first year.
Material and methods: Terminal restriction fragment length polymorphism (T-RFLP) combined with cloning and sequencing was used to identify the most predominant bacteria on the different sampling occasions. A total of 274 clones were grouped by T-RFLP and clones from each group were selected for sequencing and identified by comparison with known sequences.
Results: Differences in T-RFLP profiles and clone libraries were found between the patients, and also in changes apparent in each patient at different time-points. The main bacterial groups in the pouches resembled those of the normal colonic microbiota, with a predominance of the clostridia clusters XIVa and IV, Bacteroides and Enterobacteriaceae. Exceptions were clones with sequences resembling those of the Clostridium perfringens group, in both patients and on all sampling occasions, and the dominance of clones resembling Turicibacter in one of the patients at the time of pouch construction.
Conclusions: The pouch microbiota showed similarities to the normal colon microbiota except for the presence of clones with sequences resembling those of the C. perfringens group and Turicibacter. The bacterial composition differed between the two patients and the microbiota changed with time, suggesting that the composition is not stable during the first year.