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Helicobacter pylori (H. pylori) infection causes changes to the intestinal flora, such as small intestinal bacterial overgrowth, and increases gastric acid secretion-stimulating gastrointestinal hormones, mainly gastrin, due to a decrease in gastric acid caused by atrophic gastritis. In addition, the cellular components of H. pylori travel through the intestinal tract, so the bacterial infection affects the immune system. Therefore, the effects of H. pylori infection are observed not only in the stomach and the proximal duodenum but also in the small and large intestines. In particular, meta-analyses reported that H. pylori-infected individuals had an increased risk of colorectal adenoma and colorectal cancer. Moreover, a recent study reported that the risk of developing colorectal cancer was increased in subjects carrying H. pylori vacuolating cytotoxin A antibody. In addition, it has been reported that H. pylori infection exacerbates the symptoms of Fabry\'s disease and familial Mediterranean fever attack and is involved in irritable bowel syndrome and small intestinal ulcers. On the other hand, some studies have reported that the frequency of ulcerative colitis, Crohn\'s disease, and celiac disease is low in H. pylori-infected individuals. Thus, H. pylori infection is considered to have various effects on the small and large intestines. However, few studies have reported on these issues, and the details of their effects have not been well elucidated. Therefore, additional studies are needed.

BACKGROUND: In the early stage of acute pancreatitis (AP), a large number of cytokines induced by local pancreatic inflammation seriously damage the intestinal barrier function, and intestinal bacteria and endotoxins enter the blood, causing inflammatory storm, resulting in multiple organ failure, infectious complications, and other disorders, eventually leading to death. Intestinal failure occurs early in the course of AP, accelerating its development. As an alternative method to detect small intestinal bacterial overgrowth, the hydrogen breath test is safe, noninvasive, and convenient, reflecting the number of intestinal bacteria in AP indirectly. This study aimed to investigate the changes in intestinal bacteria measured using the hydrogen breath test in the early stage of AP to clarify the relationship between intestinal bacteria and acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Early clinical intervention and maintenance of intestinal barrier function would be highly beneficial in controlling the development of severe acute pancreatitis (SAP).
OBJECTIVE: To analyze the relationship between intestinal bacteria change and ALI/ARDS in the early stage of SAP.
METHODS: A total of 149 patients with AP admitted to the intensive care unit of the Digestive Department, Xuanwu Hospital, Capital Medical University from 2016 to 2019 were finally enrolled, following compliance with the inclusion and exclusion criteria. The results of the hydrogen breath test within 1 wk of admission were collected, and the hydrogen production rates at admission, 72 h, and 96 h were calculated. The higher the hydrogen production rates the more bacteria in the small intestine. First, according to the improved Marshall scoring system in the 2012 Atlanta Consensus on New Standards for Classification of Acute Pancreatitis, 66 patients with a PaO2/FiO2 score ≤ 1 were included in the mild AP (MAP) group, 18 patients with a PaO2/FiO2 score ≥ 2 and duration < 48 h were included in the moderately SAP (MSAP) group, and 65 patients with a PaO2/FiO2 score ≥ 2 and duration > 48 h were included in the SAP group, to analyze the correlation between intestinal bacterial overgrowth and organ failure in AP. Second, ALI (PaO2/FiO2 = 2) and ARDS (PaO2/FiO2 > 2) were defined according to the simplified diagnostic criteria proposed by the 1994 European Union Conference. The MSAP group was divided into two groups according to the PaO2/FiO2 score: 15 patients with PaO2/FiO2 score = 2 were included in group A, and three patients with score > 2 were included in group B. Similarly, the SAP group was divided into two groups: 28 patients with score = 2 were included in group C, and 37 patients with score > 2 were included in group D, to analyze the correlation between intestinal bacterial overgrowth and ALI/ARDS in AP.
RESULTS: A total of 149 patients were included: 66 patients in the MAP group, of whom 53 patients were male (80.3%) and 13 patients were female (19.7%); 18 patients in the MSAP group, of whom 13 patients were male (72.2%) and 5 patients were female (27.8%); 65 patients in the SAP group, of whom 48 patients were male (73.8%) and 17 patients were female (26.2%). There was no significant difference in interleukin-6 and procalcitonin among the MAP, MSAP, and SAP groups (P = 0.445 and P = 0.399, respectively). There was no significant difference in the growth of intestinal bacteria among the MAP, MSAP, and SAP groups (P = 0.649). There was no significant difference in the growth of small intestinal bacteria between group A and group B (P = 0.353). There was a significant difference in the growth of small intestinal bacteria between group C and group D (P = 0.038).
CONCLUSIONS: Intestinal bacterial overgrowth in the early stage of SAP is correlated with ARDS.

The effect of probiotics on small intestinal bacterial overgrowth (SIBO) in irritable bowel syndrome (IBS) has never been studied so far. In this prospective trial, five patients with IBS and SIBO and 21 patients with IBS without SIBO were administered an oral capsule containing Saccharomyces boulardii, Bifidobacterium lactis, Lactobacillus acidophilus, and Lactobacillus plantarum (Lactolevure®) every 12 h for 30 days. SIBO was defined by quantitative culture of the third part of the duodenum; IBS was defined by the Rome III criteria. Severity of symptoms was graded by the IBS severity scoring system (SSS). The primary study endpoint was the efficacy of probiotics in improvement of symptoms of IBS in patients with SIBO. Thirty days after the end of treatment, a 71.3% decrease of the total IBS score was detected in patients with IBS and SIBO compared to 10.6% in those without SIBO (p 0.017). A similar decrease was achieved among patients with constipation-predominant IBS without SIBO. Post-treatment satisfaction from bowel function was greater in patients with SIBO. Similar satisfaction improvement was found among patients with diarrhea-predominant IBS irrespective from SIBO; pain intensity score decreased in patients with constipation-predominant IBS irrespective from SIBO. The benefit of probiotics was greater among patients with a pro-inflammatory cytokine pattern in the duodenal fluid. This is the first study that prospectively demonstrated superior clinical efficacy of probiotics in patients with IBS with SIBO. Analysis also showed considerable benefit from probiotic intake regarding certain symptoms of patients with diarrhea-predominant and constipation-predominant IBS.Trial registration: ClinicalTrials.gov identifier NCT02204891.

The intestinal lumen is a host place for a wide range of microbiota and sets a unique interplay between local immune system, inflammatory cells and intestinal epithelium, forming a physical barrier against microbial invaders and toxins. Bacterial translocation is the migration of viable or nonviable microorganisms or their pathogen-associated molecular patterns, such as lipopolysaccharide, from the gut lumen to the mesenteric lymph nodes, systemic circulation and other normally sterile extraintestinal sites. A series of studies have shown that translocation of bacteria and their products across the intestinal barrier is a commonplace in patients with liver disease. The deterioration of intestinal barrier integrity and the consulting increased intestinal permeability in cirrhotic patients play a pivotal pathophysiological role in the development of severe complications as high rate of infections, spontaneous bacterial peritonitis, hepatic encephalopathy, hepatorenal syndrome, variceal bleeding, progression of liver injury and hepatocellular carcinoma. Nevertheless, the exact cellular and molecular mechanisms implicated in the phenomenon of microbial translocation in liver cirrhosis have not been fully elucidated yet.

BACKGROUND Small intestinal bacterial overgrowth (SIBO) may have a role in the pathophysiology of irritable bowel syndrome (IBS). So, the aim of this study was to assess the association between SIBO and IBS by using glucose breath test (GBT) in Kerman city as the first study in Iranian population. METHODS 107 patients with IBS and 107 healthy individuals were enrolled in our study. All the participants underwent GBT. A peak of H2 values >20 p.p.m above the basal value after glucose ingestion was considered suggestive of SIBO. SPSS software version 17 was used for data analysis. P value < 0.05 was considered as statistically significant. RESULTS Of the 107 patients with IBS, 40 had positive GBT (37.4%) compared with 14 (12.1%) out of the 107 control participants(p< 0.001). Dominant symptoms in patients with IBS were diarrhea in 36(33.6%), constipation in 12(11.2%), abdominal pain in 22(20.6%), bloating in 28(26.2%), and change in bowel habit in 9(8.4%) patients. There was not statistically significant difference among any of this IBS subgroups and positive GBT (p=0.44). CONCLUSION There is a positive association between IBS and SIBO. We suggest a Placebo-controlled bacterial eradication study for identifying the role of SIBO in IBS.