Serum supplementation favoured free-living organisms while the synthetic medium, Ham’s F-12, alone led to a larger biomass with an important polysaccharide matrix, which is also increased by subinhibitory concentrations of antibiotics [13]. For H. pylori isolation by culture, instead of using the usual agar plates, Peretz et al. inoculated blood culture bottles. The biopsies were manually diced with a scalpel, placed in 6 ml of fetal bovine serum, and transferred

LDK378 in vitro in a bottle (Bactec™ Plus Anaerobic/F Medium, Beckton Dickinson, Franklin Lakes, NJ, USA). All 25 biopsies positive by the rapid urease test, as well as one of the 15 negative biopsies, were detected positive (based on the amount of CO2 released) in a short incubation time

(average 31.6 h, extremes 26–32 h). Nevertheless, gram-positive cocci also grew in 7 samples. This method is interesting to decrease the delay of positivity [14]. Seo et al. tested cryopreservation (−70 °C) of H. pylori in gastric biopsies for more than 10 years with success [15]. Formaldehyde-fixed paraffin-embedded gastric tissue can be a good material to detect H. pylori by PCR provided that the fixation time is not too long. To give insight to the Kinase Inhibitor Library controversial issue of whether H. pylori is present or not in gastric tissue of patients with GC, a study using scorpion real-time PCR was carried out in Iran and found that 78.4% of the specimens were positive [16]. The real-time PCR described by Oleastro et al. [17] was also applied to such specimens to detect H. pylori. The 16% discordance between immunochemistry (122+) and PCR (103+) was explained essentially by a false positivity of the former due to cross reactivity. Two of the 24 negative samples were indeed PCR positive. Clarithromycin resistance was then detected by melting curve analysis in half of the positive specimens [18]. In all, 52 of 105 (50%) PCR-positive samples demonstrated resistance mutations, and it was determined that a heterogeneous population of mutated and non-mutated organisms was present in 21.15% of samples. Another possibility is to use a peptide nucleic acid fluorescence in situ hybridization (PNA-FISH) method to look for H. pylori and its resistance

to clarithromycin. However, in a prospective study, its sensitivity was only 80% for a specificity of 93.8%. The direct visualization 上海皓元 of the bacteria within the biopsy is a positive characteristic of this technique [19]. The detection of H. pylori DNA can be improved by laser capture microdissection which allows targeting of selected areas where bacteria are present [20]. The GenoTypeHelicoDR (Hain Lifescience GmbH, Nehren, Germany), a reverse hybridization assay, was also used successfully to detect H. pylori and the mutations associated with clarithromycin and levofloxacin resistance of H. pylori in South Africa [21]. Of DNA extracted from isolated H. pylori strains, 15.38% were resistant to clarithromycin, A2147G mutation being the most prevalent.