Background & Aims Foodborne illness affects 15% of the United States population each year and is a risk factor for irritable bowel syndrome (IBS). We evaluated risk of, risk factors for, and outcomes of IBS after infectious enteritis Methods We performed a systematic review of electronic databases from 1994 through August 31, 2015 to identify cohort studies of the prevalence of IBS 3 months or more after infectious enteritis. We used random effects meta-analysis to calculate the summary point prevalence of IBS after infectious enteritis, as well as relative risk (compared to individuals without infectious enteritis) and host- and enteritis-related risk factors. Results We identified 45 studies, comprising 21,421 individuals with enteritis, followed for 3 months–10 years for development of IBS. The pooled prevalence of IBS at 12 months after infectious enteritis was 10.1% (95% CI, 7.2–14.1) and at more than 12 months after infectious enteritis was 14.5% (95% CI, 7.7–25.5). Risk of IBS was 4.2-fold higher in patients who had infectious enteritis in the past 12 months than in individuals in those who had not (95% CI, 3.1–5.7); risk of IBS was 2.3-fold higher in individuals who had infectious enteritis longer than 12 months ago than in individuals who had not (95% CI, 1.8–3.0). Of patients with enteritis caused by protozoa or parasites, 41.9% developed IBS; of patients with enteritis caused bacterial infection, 13.8% developed IBS. Risk of IBS was significantly increased in women (odds ratio [OR], 2.2; 95% CI, 1.6–3.1) and with antibiotic exposure (OR, 1.7; 95% CI, 1.2–2.4), anxiety (OR, 2; 95% CI, 1.3–2.9), depression (OR, 1.5; 95% CI, 1.2–1.9), somatization (OR, 4.1; 95% CI, 2.7–6.0), neuroticism (OR, 3.3; 95% CI, 1.6–6.5), and clinical indicators of enteritis severity. There was a considerable level of heterogeneity among studies. Conclusion In a systematic review and meta-analysis, we found more than 10% of patients with infectious enteritis to later develop IBS; risk of IBS was 4-fold higher than in individuals who did not have infectious enteritis, although there was heterogeneity among studies analyzed. Women—particularly those with severe enteritis—are at increased risk for developing IBS, as are individuals with psychological distress and users of antibiotics during the enteritis.

ObjectiveThe intestinal lumen contains several proteases. Our aim was to determine the role of faecal proteases in mediating barrier dysfunction and symptoms in IBS.Design39 patients with IBS and 25 healthy volunteers completed questionnaires, assessments of in vivo permeability, ex vivo colonic barrier function in Ussing chambers, tight junction (TJ) proteins, ultrastructural morphology and 16 s sequencing of faecal microbiota rRNA. A casein-based assay was used to measure proteolytic activity (PA) in faecal supernatants (FSNs). Colonic barrier function was determined in mice (ex-germ free) humanised with microbial communities associated with different human PA states.ResultsPatients with IBS had higher faecal PA than healthy volunteers. 8/20 postinfection IBS (PI-IBS) and 3/19 constipation- predominant IBS had high PA (>95th percentile). High-PA patients had more and looser bowel movements, greater symptom severity and higher in vivo and ex vivo colonic permeability. High-PA FSNs increased paracellular permeability, decreased occludin and increased phosphorylated myosin light chain (pMLC) expression. Serine but not cysteine protease inhibitor significantly blocked high-PA FSN effects on barrier. The effects on barrier were diminished by pharmacological or siRNA inhibition of protease activated receptor-2 (PAR-2). Patients with high-PA IBS had lower occludin expression, wider TJs on biopsies and reduced microbial diversity than patients with low PA. Mice humanised with high-PA IBS microbiota had greater in vivo permeability than those with low-PA microbiota.ConclusionA subset of patients with IBS, especially in PI-IBS, has substantially high faecal PA, greater symptoms, impaired barrier and reduced microbial diversity. Commensal microbiota affects luminal PA that can influence host barrier function.

Background Gastrointestinal (GI) and non-GI disorders are associated with altered intestinal permeability, which can be measured in vivo by urinary excretion after oral lactulose and mannitol ingestion. Inadvertent dietary consumption of 12Carbon (12C, regular) mannitol in food or from other sources may interfere with the test’s interpretation. 13Carbon (13C) constitutes 1% of carbon in nature and 13C mannitol is a stable isotope. Our aim was to determine performance of 13C mannitol for measurement of intestinal permeability. Methods Ten healthy volunteers underwent intestinal permeability assay using co-administered 12C mannitol, 13C mannitol and lactulose, followed by timed urine collections. Urinary sugar concentrations were measured using tandem high performance liquid chromatography-mass spectrometry. Key Results We found that 13C mannitol can be distinguishable from 12C mannitol on tandem mass spectrometry. Additionally, 13C mannitol had ~20-fold lower baseline contamination compared to 12C mannitol. We describe here the 13C mannitol assay method for measurement of intestinal permeability. Conclusions & Inferences In conclusion, 13C mannitol is superior to 12C mannitol for measurement of intestinal permeability. It avoids issues with baseline contamination and erratic excretions during the testing period.