Validation of four Helicobacter pylori rapid blood tests in a multi-ethnic Asian population

AIM: To validate the accuracy of four rapid blood tests in the diagnosis of Helicobacter pylori.METHODS: Consecutive dyspeptic patients scheduled for endoscopy at the National University Hospital,Singapore, were interviewed and had blood drawn for serology. The first 109 patients were tested with BM-test (BM), Pyloriset Screen (PS) and QuickVue (QV), and the next 99 subjects were tested with PS and Unigold (UG).Endoscopies were performed blinded to rapid blood test results and biopsies were taken for culture and rapid urease test. Urea breath tests were performed after endoscopies. The rapid blood test results were compared with four reference tests (rapid urease test, culture,serology, and breath test).RESULTS: The study population composed of 208patients (mean age 43.1 years; range 18-73 years; 119males; 174 Chinese). The number of evaluable patientsfor BM, QV, UG and PS were 102, 102, 95, and 197,respectively. The sensitivity and specificity, respectively were: PS 80.2%, 95.8%; UG 55.9%, 100%; QV 43.3%,100%; BM 67.2%, 97.1%.CONCLUSION: The rapid blood test kits showed high specificity and positive predictive value (97-100%), while sensitivity and negative predictive value ranged widely (43%-80% and 47%-73%, respectively). Among test kits, PS showed the best sensitivity (80%), best negative predictive value (73%) and best negative likelihood ratio (0.207). PS had a specificity of 96%, positive predictive value of 97% and positive likelihood ratio of 19.1.

The effects of probiotics administration on the milk production,milk components and fecal bacteria microbiota of dairy cows

Probiotics administration can improve host health. This study aims to determine the effects of probiotics （Lactobacillus casei Zhang and Lactobacillus plantarum P-8） administration on milk production, milk func- tional components, milk composition, and fecal microbiota of dairy cows. Variations in the fecal bacteria microbiota between treatments were assessed based on 16S rRNA profiles determined by PacBio single molecule real-time sequencing technology. The probiotics supplementation significantly increased the milk production and the contents of milk immunoglobulin C （IgG）, lactoferrin （LTF）, lysozyme （LYS） and lactoperoxidase （LP）, while the somatic cell counts （SCC） significantly decreased （P〈0.01）. However, no significant difference was found in the milk fat, protein and lactose contents （P 〉 0.05）. Although the probiotics supplementation did not change the fecal bacteria richness and diversity, significantly more rumen fermentative bacteria （ Bacteroides, Roseburia, Ruminococcus, CIostridium, Coprococcus and Dorea） and beneficial bacteria （Faecalibacterium prausnitzii） were found in the probiotics treatment group. Meanwhile, some opportunistic pathogens e.g. Bacillus cereus, Cronobacter sakazakii and Alkaliphilus oremlandii, were suppressed. Additionally, we found some correlations between the milk production, milk components and fecal bacteria. To sum up, our study demonstrated the beneficial effects of probiotics application in improving the quality and quantity of cow milk production.

Infant intestinal Enterococcus faecalis down-regulates inflammatory responses in human intestinal cell lines

AIM: To investigate the ability of Lactic acid bacteria (LAB) to modulate inflammatory reaction in human intestinal cell lines (Caco-2, HT-29 and HCT116). Different strains of LAB isolated from new born infants and fermented milk, together with the strains obtained from culture collections were tested.METHODS: LABs were treated with human intestinal cell lines. ELISA was used to detect IL-8 and TGF-β protein secretion. Cytokines and Toll like receptors (TLRs) gene expression were assessed using RT-PCR. Conditional medium, sonicated bacteria and UV killed bacteria were used to find the effecter molecules on the bacteria. Carbohydrate oxidation and protein digestion were applied to figure out the molecules' residues. Adhesion assays were further carried out.RESULTS: It was found that Enterococcus faecalis is the main immune modulator among the LABs by downregulation of IL-8 secretion and upregulation of TGF-β. Strikingly, the effect was only observed in four strains of E. faecalis out of the 27 isolated and tested. This implies strain dependent immunomodulation in the host. In addition, E. faecalis may regulate inflammatory responses through TLR3, TLR4, TLR9 and TRAF6. Carbohydrates on the bacterial cell surface are involved in both its adhesion to intestinal cells and regulation of inflammatory responses in the host. CONCLUSION: These data provide a case for the modulation of intestinal mucosal immunity in which specific strains of E. faecalis have uniquely evolved to maintain colonic homeostasis and regulate inflammatory responses.

The Molecular Mechanism of Interaction between Sushi Peptide and Pseudomonas Endotoxin

Septic shock is caused by Gram-negative bacterial infection. Lipopolysaccharide （LPS） is the bioactive molecule present on the outer membrane of the Gram-negative bacteria. It is generally thought that LPS interacts with sensors on the host cell membrane to activate the intracellular signaling pathway resulting in the overproduction of cytokines such as TNF-α This causes inflammation and ultimately, septic shock. Lipid A is the pharmacophore of the LPS molecule. Thus, developing bio-molecules which are capable of binding LPS at high affinity, especially to the lipid A moiety is an efficient way to neutralize the LPS toxicity. Factor C, a serine protease in the horseshoe crab ameobocytes, is sensitive to trace levels of LPS. We have derived Sushi peptides from the LPS-binding domains of Factor C. Our earlier study showed that the Sushi peptides inhibit LPS-induced septic shock in mice. Here, we demonstrate that the molecular interaction between LPS and Sushi 1 peptide is supported by the hydrophobic interaction between the lipid tail of LPS and Sushi 1 peptide. Furthermore, in the presence of LPS, the peptide transitions from a random structure into an α-helical conformation and it disrupts LPS aggregates, hence, neutralizing the LPS toxicity.