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OBJECTIVES: Helicobacter pylori infection has not been well studied in older people, especially in hospitalized, frail patients. The aim of our study was to evaluate the prevalence of the infection in this population using five H. pylori diagnostic tests.DESIGN: Prospective observational study.SETTING: Geriatric acute care unit of the Department of Geriatrics (Hôpital Xavier Arnozan, Pessac, France).PARTICIPANTS: One hundred seven consecutively hospitalized patients with a diagnostic indication for upper gastrointestinal endoscopy.MEASUREMENTS: Geriatric assessment, information on drug intake, indication/results of gastric endoscopy, and results of H. pylori infection diagnostic tests (culture and histological analysis on biopsy specimens, serology, 13carbon‐urea breath test (13C‐UBT), detection of H. pylori stool antigens (HpSA)) were assessed for each included patient.RESULTS: Fifty‐one patients (47.7%) were H. pylori positive with at least one test. 13C‐UBT was more frequently positive than the other four tests, with a significant difference from culture, histological analysis, and HpSA (P < .05). Positive 13C‐UBT results were significantly associated with H. pylori presence using histological analysis and neutrophil activity of the antrum and corpus. Antibiotic treatments significantly decreased the positivity rate of all of the tests performed, and severe corpus atrophy decreased the positivity rate of culture, histological analysis, and HpSA.CONCLUSIONS: Almost one‐third of the H. pylori–positive patients would have remained undetected without performing the 13C‐UBT. The low prevalence of H. pylori detection in these hospitalized, frail patients may be explained by the high frequency of current and previous antibiotic treatments.

A PCR protocol was developed to detect Helicobacter pylori in human stool specimens. This protocol was based on the association of a magnetic immuno-PCR assay with a technique to remove inhibitors (agaroseembedded DNA preparation). Of the 47 H. pylori-positive and 57 H. pylori-negative patients included in this study, 38 were positive and 66 were negative by this new protocol. The sensitivity, specificity, and predictive values for a positive or a negative result were 80.9% (95% confidence interval [CI], 66.3 to 90.4), 100% (95% CI, 92.1 to 100), 100% (95% CI, 88.6 to 100), and 86.4% (95% CI, 75.2 to 93.2), respectively.The high clinical relevance of Helicobacter pylori infection has stimulated the development of numerous diagnostic methods. These methods can be classified as invasive, (i.e., those that require an endoscopy to detect H. pylori directly in gastric biopsy specimens) or noninvasive (i.e., based on the study of various samples (serum, breath air, urine, etc.)), which indirectly indicate the presence of H. pylori.Stool specimens constitute a sample of easy, noninvasive access and consequently of high potential interest for the development of a direct method of H. pylori detection. PCR is a powerful technique for the detection of target DNA in various clinical specimens, but its application to stool specimens has been limited due to the presence of substances inhibiting the reaction. Numerous attempts to detect H. pylori by PCR in stool samples have been made, with controversial results ( Difficulty in eliminating PCR inhibitors from stool specimens has been extensively reported (4,5,8,12). Some authors have claimed to be successful, but usually only after applying complex procedures that are difficult to implement routinely.The aim of this study was to develop a PCR protocol to detect H. pylori in human stool specimens that is simple enough to be used routinely. For this purpose, we associated a magnetic immuno-PCR assay (MIPA) with a technique to remove inhibitors that was recently described (11).Clinical samples. One hundred four consecutive, untreated, dyspeptic patients (69 male, 35 female; mean age, 50 years; range, 17 to 87 years) who were consulting gastroenterologists for dyspepsia in Bordeaux, France, were included in the study. Exclusion criteria were as follows: H. pylori eradication treatment in the previous 6 months; consumption of antibiotics in the previous month; or consumption of antisecretory drugs, bismuth salts, or sucralfate in the previous 2 weeks. A history of coagulopathy or other disorders that are contraindications for endoscopy and/or biopsy sampling was also a reason for exclusion. For each patient, biopsies were taken for culture, histological examination, urease test (UT), and PCR. A urea breath test (UBT) and a serological test were also performed as previously described (9).A patient was classified as being H. pylori positive on the basis of (i) a positive culture; or, in the case of a negative culture, (ii) both a positive histological examination and a positive UT (C...

Helicobacter pylori is a Gram-negative bacterium that is associated with the development of peptic ulcers and gastric carcinoma in humans. This species appears to be one of the most genetically variable bacteria described to date. The overall level of heterogeneity within strains of this organism was determined by comparing the genome sequences of two reference strains, J99 and 26695. The aim of this study was to measure the genetic diversity within strains of H. pylori by looking for strain-specific genes in nine H. pylori strains isolated from patients suffering from chronic gastritis (nl3), duodenal ulcers (nl3) or gastric cancer (nl3). Seven loci that contained strain-specific genes in strains J99 and 26695 were studied. These regions were subsequently amplified from most of the clinical isolates studied and their sequences were determined. ORFs were predicted from the sequence data and were compared to sequences within the databases. The results showed that the genes flanking the ORFs specific to either strain J99 or strain 26695 were also present in a similar configuration in the genomes of the nine clinical isolates. Moreover, in most regions, ORFs homologous to those found in the corresponding loci in the two reference strains were detected. However, in 10 regions, genes similar to those located at another locus in the genome of J99 or 26695 were found. Finally, six strain-specific genes were identified in three regions of three of the H. pylori strains isolated from patients with duodenal ulcers (nl2) and gastric cancer (nl1). Of these six genes, five were putative genes and one was an orthologue of a gene encoding a transposase in Thermotoga maritima. However, no association with disease was found for these genes.

Knowledge of the cagA status of Helicobacter pylori infection could be relevant for the treatment and prevention of possible complications of infection. This goal can be achieved using serology since CagA is highly immunogenic. The aim of this study was to correlate the presence of the cagA gene detected by polymerase chain reaction (PCR) with the presence of serum antibodies against the CagA protein using a recently available commercial immunoblotting assay, the Helico Blot 2.1 kit. Considering the results obtained by PCR, Helico Blot 2.1 presented sensitivity, specificity, and positive and negative predictive values for CagA status of 97.4%, 87.7%, 80.9% and 98.5%, respectively.