(1)H NMR spectroscopy of aqueous fecal extracts has been used to investigate differences in metabolic activity of gut microbiota in patients with ulcerative colitis (UC) (n = 13), irritable bowel syndrome (IBS) (n = 10), and healthy controls (C) (n = 22). Up to four samples per individual were collected over 2 years giving a total of 124 samples. Multivariate discriminant analysis, based on NMR data from all three groups, was able to predict UC and C group membership with good sensitivity and specificity; classification of IBS samples was less successful and could not be used for diagnosis. Trends were detected toward increased taurine and cadaverine levels in UC with increased bile acid and decreased branched chain fatty acids in IBS relative to controls; changes in short chain fatty acids and amino acids were not significant. Previous PCR-denaturing gradient gel electrophoresis (PCR-DGGE) analysis of the same fecal material had shown alterations of the gut microbiota when comparing UC and IBS groups with controls. Hierarchical cluster analysis showed that DGGE profiles from the same individual were stable over time, but NMR spectra were more variable; canonical correlation analysis of NMR and DGGE data partly separated the three groups and revealed a correlation between the gut microbiota profile and metabolite composition.

BackgroundPrevious studies suggest a link between gut microbiota and the development of ulcerative colitis (UC) and irritable bowel syndrome (IBS). Our aim was to investigate any quantitative differences in faecal bacterial compositions in UC and IBS patients compared to healthy controls, and to identify individual bacterial species that contribute to these differences.MethodsFaecal microbiota of 13 UC patients, 11 IBS patients and 22 healthy volunteers were analysed by PCR-Denaturing Gradient Gel Electrophoresis (DGGE) using universal and Bacteroides specific primers. The data obtained were normalized using in-house developed statistical method and interrogated by multivariate approaches. The differentiated bands were excised and identified by sequencing the V3 region of the 16S rRNA genes.ResultsBand profiles revealed that number of predominant faecal bacteria were significantly different between UC, IBS and control group (p < 10-4). By assessing the mean band numbers in UC (37 ± 5) and IBS (39 ± 6), compared to the controls (45 ± 3), a significant decrease in bacterial species is suggested (p = 0.01). There were no significant differences between IBS and UC. Biodiversity of the bacterial species was significantly lower in UC (μ = 2.94, σ = 0.29) and IBS patients (μ = 2.90, σ = 0.38) than controls (μ = 3.25, σ = 0.16; p = 0.01). Moreover, similarity indices revealed greater biological variability of predominant bacteria in UC and IBS compared to the controls (median Dice coefficients 76.1% (IQR 70.9 - 83.1), 73.8% (IQR 67.0 - 77.5) and 82.9% (IQR 79.1 - 86.7) respectively). DNA sequencing of discriminating bands suggest that the presence of Bacteroides vulgatus, B. ovatus, B. uniformis, and Parabacteroides sp. in healthy volunteers distinguishes them from IBS and UC patients. DGGE profiles of Bacteroides species revealed a decrease of Bacteroides community in UC relative to IBS and controls.ConclusionMolecular profiling of faecal bacteria revealed abnormalities of intestinal microbiota in UC and IBS patients, while different patterns of Bacteroides species loss in particular, were associated with UC and IBS.

BACKGROUND: Bloodstream infections (BSI) are a major complication of hemodialysis. The risk of infection among hemodialysis patients is usually associated with the dialysis procedure itself, specifically the means of vascular access.OBJECTIVES: Estimate the rate of BSI and assess factors possibly associated with BSI.DESIGN: Analytical retrospective medical record review.SETTING: Hemodialysis unit in a tertiary care center.PATIENTS AND METHODS: Adult patients (18–60 years old) who had hemodialysis as first renal replacement therapy in the 20-month period from January 2014 to August 2016 were included in this study. Demographic and clinical characteristics were used in a multivariate logistic regression to assess factors that might be associated with BSI.MAIN OUTCOME MEASURES: The rate of BSI and associated factors among chronic hemodialysis outpatients.SAMPLE SIZE AND CHARACTERISTICS: 160 outpatients on hemodialysis, median (IQR) age 47.7 (37.0–56.0) years, males (60.6%).RESULTS: The rate of BSI was 0.4 per 100 patient-months. Multivariate logistic regression revealed that patients who had central venous catheters had the highest risk for BSI (odds ratio: 10.088; 95% CI= 2.595–39.215; P=.001) compared with arteriovenous fistulas. Gram-negative bacteria were isolated in 54.6% of cases, with coagulase-negative Staphylococcus the most frequent isolate (18.2%), followed by Klebsiella pneumoniae and Enterobacteriaceae (15.2%, each).CONCLUSIONS: The type of vascular access type is the main risk factor associated with BSI in hemodialysis patients. The arteriovenous fistula, which has a lower infection rate compared to the catheter, is the best available option for hemodialysis patients.LIMITATIONS: Retrospective, single center and relatively small sample size.CONFLICT OF INTEREST: None.