Differentiation of meat-related microorganisms using paper-based surface-enhanced Raman spectroscopy combined with multivariate statistical analysis
TALANTA
Authors: Breuch, Rene; Klein, Daniel; Siefke, Eleni; Hebel, Martin; Herbert, Ulrike; Wickleder, Claudia; Kaul, Peter
Abstract
Surface-enhanced Raman spectroscopy (SERS) with subsequent chemometric evaluation was performed for the rapid and non-destructive differentiation of seven important meat-associated microorganisms, namely Brochothrix thermosphacta DSM 20171(T), Pseudomonas fluorescens DSM 4358, Salmonella enterica subsp. enterica sv. Enteritidis DSM 14221, Listeria monocytogenes DSM 19094, Micrococcus luteus DSM 20030(T), Escherichia coli HB101 and Bacillus thuringiensis sv. israelensis DSM 5724. A simple method for collecting spectra from commercial paper-based SERS substrates without any laborious pre-treatments was used. In order to prepare the spectroscopic data for classification at genera level with a subsequent chemometric evaluation consisting of principal component analysis and discriminant analysis, a data pre-processing method with spike correction and sum normalisation was performed. Because of the spike correction rather than exclusion, and therefore the use of a balanced data set, the multivariate analysis of the data is significantly resilient and meaningful. The analysis showed that the differentiation of meat-associated microorganisms and thereby the detection of important meatrelated pathogenic bacteria was successful on genera level and a cross-validation as well as a classification of ungrouped data showed promising results, with 99.5% and 97.5%, respectively.
Mucosal Biomarker of Innate Immune Activation Predicts Response to Vedolizumab in Crohn's Disease
INFLAMMATORY BOWEL DISEASES
Authors: Osterman, Mark T.; Gordon, Ilyssa O.; Davis, Elisabeth M.; Ciorba, Matthew; Glover, Sarah C.; Abraham, Bincy; Khan, Freeha; Guo, Xueyan; Yee, Eric U.; Allard, Felicia D.; Claggett, Brian; Shen, Bo; Liu, Julia J.
Abstract
Objective: Mucosal barrier dysfunction plays a crucial role in intestinal inflammation in Crohn's disease (CD). Intestinal epithelial cell (IEC) death resulting from innate immune activation, termed pyroptosis, was recently found to be a cause of this barrier defect. The aim of this study was to determine the predictive value of pretreatment ileal biopsy pyroptosis as a biomarker for clinical response to vedolizumab in CD. Design: Crohn's disease patients ranging 18 to 80 years old from 5 IBD centers with pre-vedolizumab ileal biopsies during colonoscopy were enrolled. Biopsies were stained for activated caspases, and levels of ileal IEC pyroptosis levels were quantified. The primary outcome was clinical response 6 months after therapy, defined as a reduction of Harvey-Bradshaw Index (HBI) of >= 5 points from baseline. Secondary outcomes included clinical remission, defined as HBI <5, and endoscopic improvement, as measured by the Simple Endoscopic Score for Crohn's Disease (SES-CD). Results: One hundred CD patients (45 male, 55 female), median age 47 (19, 78) years, were included; clinical response rate was 60%, and clinical remission was 36%. The response rate in patients with ileal pyroptosis <14 positive cells per 1000 IECs was significantly higher than those above the threshold: 89% (25 of 28) vs 49% (35 of 72), odds ratio (OR) 8.8 (95% CI, 2.3-48.6; P < 0.001). Corresponding remission rates were 54% (15 of 28) vs 29% (21 of 72; OR 2.8 [1.03-7.59; P = 0.036]). For endoscopic improvement, ileal pyroptosis of 22 positive cells per 1000 IECs was the optimal threshold that determines the magnitude SES-CD change. Conclusions: Ileal biopsy IEC pyroptosis was predictive of clinical response and endoscopic improvement to vedolizmab in CD patients.