Summary Akkermansia muciniphila (A. muciniphila), an intestinal symbiont colonizing in the mucosal layer, is considered to be a promising candidate as probiotics. A. muciniphila is known to have an important value in improving the host metabolic functions and immune responses. Moreover, A. muciniphila may have a value in modifying cancer treatment. However, most of the current researches focus on the correlation between A. muciniphila and diseases, and little is known about the causal relationship between them. Few intervention studies on A. muciniphila are limited to animal experiments, and limited studies have explored its safety and efficacy in humans. Therefore, a critical analysis of the current knowledge in A. muciniphila will play an important foundation for it to be defined as a new beneficial microbe. This article will review the bacteriological characteristics and safety of A. muciniphila, as well as its causal relationship with metabolic disorders, immune diseases and cancer therapy.

BackgroundAntibiotic-associated diarrhea (AAD) is a risk factor for exacerbating the outcome of critically ill patients. Dysbiosis induced by the exposure to antibiotics reveals the potential therapeutic role of fecal microbiota transplantation (FMT) in these patients. Herein, we aimed to evaluate the safety and potential benefit of rescue FMT for AAD in critically ill patients.MethodsA series of critically ill patients with AAD received rescue FMT from Chinese fmtBank, from September 2015 to February 2019. Adverse events (AEs) and rescue FMT success which focused on the improvement of abdominal symptoms and post-ICU survival rate during a minimum of 12 weeks follow-up were assessed.ResultsTwenty critically ill patients with AAD underwent rescue FMT, and 18 of them were included for analysis. The mean of Acute Physiology and Chronic Health Evaluation (APACHE) II scores at intensive care unit (ICU) admission was 21.7 ± 8.3 (range 11–37). Thirteen patients received FMT through nasojejunal tube, four through gastroscopy, and one through enema. Patients were treated with four (4.2 ± 2.1, range 2–9) types of antibiotics before and during the onset of AAD. 38.9% (7/18) of patients had FMT-related AEs during follow-up, including increased diarrhea frequency, abdominal pain, increased serum amylase, and fever. Eight deaths unrelated to FMT occurred during follow-up. One hundred percent (2/2) of abdominal pain, 86.7% (13/15) of diarrhea, 69.2% (9/13) of abdominal distention, and 50% (1/2) of hematochezia were improved after FMT. 44.4% (8/18) of patients recovered from abdominal symptoms without recurrence and survived for a minimum of 12 weeks after being discharged from ICU.ConclusionIn this case series studying the use of FMT in critically ill patients with AAD, good clinical outcomes without infectious complications were observed. These findings could potentially encourage researchers to set up new clinical trials that will provide more insight into the potential benefit and safety of the procedure in the ICU.Trial registrationClinicalTrials.gov, Number NCT03895593. Registered 29 March 2019 (retrospectively registered).

Background Colonic transendoscopic enteral tubing (TET) refers to colonic transendoscopic tube-delivered enteral therapy. Colonic TET has been successfully used for frequent colonic administration of drugs or multiple fecal microbiota transplantations (FMTs). This prospective observational study aimed to evaluate possible factors affecting methodology, feasibility and safety of colonic TET. Methods Patients who underwent colonic TET at our center from October 2014 to November 2018 were included. The feasibility, efficacy, and safety of TET were evaluated. Results In total, 224 patients were analyzed. The success rate of TET was 100%. The median retention time of TET tube within the colonic lumen was 8.5 (IQR 7–11) days in 158 patients with tube falling out spontaneously, and the maximum retention time was up to 28 days. These patients were divided into the short-retention group (≤ 8.5 days) and the long-retention group (> 8.5 days). Univariate and multivariate analysis demonstrated that the type of endoscopic clip (p = 0.001) was an independent factor for the retention time. The larger clips as well as a greater number of clips significantly affected the retention time (p = 0.013). No severe adverse event was observed during and after TET. Conclusions Colonic TET is a feasible, practical, and safe colon-targeted drug delivery technique with a high degree of patients’ satisfaction. Two to four large endoscopic clips are recommended to maintain stability of the TET tube within the colon for over 7 days.

Aim. Colonic transendoscopic enteral tubing (TET) has been used for delivering fecal microbiota transplantation by washed preparation since 2015, which was recently named as washed microbiota transplantation (WMT). However, there are few reports available regarding the feasibility and safety of these studies in low-age population. This study is aimed at evaluating the safety, feasibility, and value of colonic TET in 3-7 years old children. Methods. All patients aged 3-7 years who underwent colonic TET in our center for WMT or medication were prospectively evaluated. The feasibility and safety of TET were evaluated. A questionnaire was completed by the children’s parents to evaluate the children’s response to the colonic TET as well as the parent’s satisfaction. Results. Forty-seven children were included (mean age 5 years). TET was implemented into the colon of all the patients, and the success rate of the procedure was 100%. The median retention time of TET tube within the colon was 6 (IQR 5-7) days in 45 patients with tube falling out spontaneously, and the maximum retention time was up to 21 days. Multivariate analysis demonstrated that endoscopic clip number ( P = 0.009 ) was an independent contributing factor for the retaining time of tube. With increase in the number of large clips, the retention time of TET tube was prolonged. No discomfort was reported during injection of the microbiota or medication suspension through the TET tube. During the follow-up, no severe adverse events were observed. All children’s parents were satisfied with TET. Interestingly, the proportion of children’s parents choosing TET as the delivery way of WMT increased from 29.79% before to 70.21% after TET ( P < 0.001 ). Conclusions. This study, for the first time, demonstrates that colonic TET is a novel, safe, and convenient colonic delivery way for WMT and medication in children aged 3-7 years.