Appropriate storage of fecal samples is a critical step for unbiased analysis in human microbiome studies. The purpose of this study was to evaluate the stability of the fecal microbial community for up to 18 months. Ten healthy volunteers provided fecal samples at the Jeonbuk National University Hospital. Stool samples were stored under the following six conditions: four different storage temperatures (− 70 °C, − 20 °C, 4 °C, and room temperature [20–25 °C]) and two different collection tubes (OMNIgene-Gut and DNA/RNA shield-fecal collection tubes). The gut microbiome was analyzed with 16S rRNA sequencing. We compared the taxonomic composition, alpha diversity, beta diversity and inferred pathway abundance between the baseline and 18 months after storage. Samples collected in the DNA/RNA Shield-fecal collection tubes showed the best performance in preservation of the taxonomic composition at 18 months. Pairwise differences in alpha diversity metrics showed the least deviation from zero. The PERMANOVA test showed non-significant change of beta diversity metrics (Unweighted Unifrac: q-value 0.268; Weighted Unifrac: q-value 0.848). The functional stability was significantly well preserved in the DNA/RNA Shield-fecal collection tubes (adjusted p value < 0.05). Our results demonstrate the use of the DNA/RNA Shield-fecal collection tube as an alternative storage method for fecal samples to preserve the taxonomic and functional stability of the microbiome over a long term.

We aimed to evaluate the efficacy of sending educational video clips via smartphone mobile messenger (SMM) on enhancing bowel preparation before colonoscopy. This was a prospective, endoscopist-blinded, randomized controlled study. Patients in the SMM group received two video clips sent via SMM that explained the diet and regimen for bowel preparation, whereas those in the control group did not receive any video clips. We compared the quality of bowel preparation between the two groups, which was assessed by an endoscopist using the Ottawa scale. Between August and November 2014, 140 patients in the SMM group and 141 patients in the control group underwent colonoscopic examination. The total Ottawa score of the SMM group was significantly lower than that of the control group (5.47±1.74 vs. 5.97±1.78, p=0.018). These results were particularly prominent in the younger age group; the total Ottawa score of patents in the SMM group aged <40 years was significantly lower than that of patients in the control group aged <40 years (5.10±1.55 vs. 6.22±2.33, p=0.034). We demonstrated that sending educational video clips via SMM could result in better bowel preparation, especially in the younger age group.

Recently, a number of studies have reported that the gut microbiota could contribute to human conditions, including obesity, inflammation, cancer development, and behavior. We hypothesized that the composition and distribution of gut microbiota are different according to stool frequency, and attempted to identify the association between gut microbiota and stool frequency. We collected fecal samples from healthy individuals divided into 3 groups according to stool frequency: group 1, a small number of defecation (≤2 times/wk); group 2, normal defecation (1 time/day or 1 time/2 day); and group 3, a large number of defecation (≥2-3 times/day). We evaluated the composition and distribution of the gut microbiota in each group via 16S rRNA-based taxonomic profiling of the fecal samples. Fecal samples were collected from a total of 60 individuals (31 men and 29 women, aged 34.1±5.88 years), and each group comprised 20 individuals. The microbial richness of group 1 was significantly higher than that of group 3 and tended to decrease with increasing number of defecation (P<0.05). The biological community composition was fairly different according to the number of defecation, and Bacteroidetes to Firmicutes ratio was higher in group 1 than in the other groups. Moreover, we found specific strains at the family and genus levels in groups 1 and 3. Bacteroidetes to Firmicutes ratio and the abundance of Bifidobacterium were different according to the stool frequency, and specific bacteria were identified in the subjects with large and small numbers of defecation, respectively. These findings suggest that stool frequency might be associated with the richness and community composition of the gut microbiota.

Impact of Fusobacterium nucleatum in the gastrointestinal tract on natural killer cells

Background: Current evidence support that the gut microbiota plays a potential role in obesity. Bariatric surgery can reduce excess weight and decrease the risk of life-threatening weight-related health problems and may also influence gut microbiota. In this study, we aimed to investigate the changes in gut microbiota before and after bariatric surgery and evaluate the association of the gut microbial shift and altered body mass index (BMI) after bariatric surgery.Methods: Between January 2019 and July 2020, stools from 58 patients scheduled for bariatric surgery were collected. Six months after bariatric surgery, stools from 22 of these patients were re-collected, and the changes in gut microbiota before and after bariatric surgery were evaluated. In addition, the differences in gut microbiota between patients with severe obesity (BMI >35 kg/m2, n=42) and healthy volunteers with normal BMI (18.8 to 22.8 kg/m2, n=41) were investigated.Results: The gut microbiota of patients who underwent bariatric surgery showed increased α-diversity and differed β-diversity compared with those before surgery. Interestingly, Blautia was decreased and Bacteriodes was increased at the genus level after bariatric surgery. Further, the Blautia/Bacteroides ratio showed a positive correlation with BMI. To validate these results, we compared the gut microbiota from severely obese patients with high BMI with those from healthy volunteers and demonstrated that the Blautia/Bacteroides ratio correlated positively with BMI.Conclusion: In the gut microbial analysis of patients who underwent bariatric surgery, we presented that the Blautia/Bacteroides ratio had changed after bariatric surgery and showed a positive correlation with BMI.

In this study, we compared the efficacy and safety of etomidate with those of propofol or midazolam for the maintenance of sedation during endoscopy. The study enrolled patients who underwent sedative endoscopy in our hospital and divided them into three groups. Patients in each group were administered midazolam as induction therapy and were subsequently administered either midazolam (M + M group), propofol (M + P group), or etomidate (M + E group) as maintenance medication. The primary outcome was overall cardiovascular and respiratory adverse events. In total, 105 patients who underwent sedative endoscopic examination were enrolled. The outcomes related to the procedure and sedation were not significantly different among the groups. Overall cardiovascular and respiratory adverse events were observed in 9 patients (25.7%) in the M + M group, 8 patients (23.5%) in the M + P group, and 10 patients (27.8%) in the M + E group. The logistic regression analysis revealed that etomidate use was not an independent risk factor for overall cardiovascular and respiratory adverse events. The outcomes following the use of etomidate for maintenance after induction with midazolam for sedation in upper gastrointestinal endoscopy were not inferior to those following midazolam or propofol use from the perspectives of safety and efficacy.