80 (95% CI 1.71–13.5) versus infection with cagA negative/vacA s2m2 strains . The main limitation in detecting H. pylori DNA in feces is the presence of inhibitors of the Taq polymerase used, which have been shown to be complex polysaccharides
. Until now, all of the DNA extraction methods proposed have failed to lead to a good sensitivity of the PCR. A new method adapted from extraction of Mycobacterial DNA in clinical samples was proposed, based on a selective hybridization of target www.selleckchem.com/products/bmn-673.html DNA with biotin-labeled probes, followed by DNA isolation with streptavidin-coated magnetic beads. It was tested in the model of H. pylori-infected gerbils with fecal samples analyzed 1, 4, and 10 days postinfection. The detection limit obtained was one bacterial cell per 100 mg of stool after heating, i.e. a 10-fold increase in sensitivity compared with a commercially available stool DNA extraction kit . Detection of H. pylori in dental plaque is even more challenging for another reason, i.e. other members of the Epsilonproteobacteriaceae can be present and lead to false positivity. Using two genes versus one as a target,
Chaudhry et al. decreased the rate of positivity from 73% to 52% . In another study using PCR and Southern blotting, click here there was a positive correlation between H. pylori positivity in gastric biopsies and the oral cavity, suggesting the existence of an oral reservoir . There were very few papers in this area this year. Petrovic et al. evaluated a 14C UBT (Nuclear Sciences, Vinca, Serbia) undertaken in fasting Serbian patients 30 minutes after a urease capsule containing a 37 kBq/dose of 14C. A positive test, defined as a 80% rise in test values compared with the baseline breath pre 14C dose, when compared with histology and biopsy urease test had high sensitivity (94.9%), 100% specificity and thus high positive (100%) and negative (96.3%) predictive values . In another study, using the 13C-UBT, Delta Over Baseline values did not correlate with
H. pylori antibiotic CYTH4 resistance . The UBT has for some time been considered the gold standard noninvasive test. A 2009 systematic review by Nocon et al. of 30 studies that directly compared the 13C-UBT to biopsy-based tests as the gold standard confirmed this viewpoint. The 13C-UBT showed higher sensitivity and specificity than the IgG serology and stool antigen tests in the majority of studies . In comparison with the biopsy urease test, results for sensitivity were inconsistent, but the specificity was slightly higher for the 13C-UBT . There were insufficient results for comparisons between the 13C-UBT and the 14C-UBTs, histology and PCR to determine any significant differences . Many of the evaluations of the stool antigen tests (SATs) reported this year from Eastern Europe and beyond in adults, found the SATs to be less accurate than in previous reports. Da Silva et al.