2fA new Helicobacter species that colonizes the colonic mucosa of Wistar and Holtzman rats was isolated and characterized. This bacterium was gram negative, its cells were rod shaped with pointed ends, and its protoplasmic cylinder was entwined with periplasmic fibers. It was catalase and oxidase positive, rapidly hydrolyzed urea, and was susceptible to metronidazole and resistant to cephalothin and nalidixic acid. The new organism was microaerophilic and grew at 42"C, a feature that differentiates it from two other murine intestine colonizers, Helicobacter hepaticus and Helicobacter muridarum. On the basis of 16s rRNA sequence analysis data, the new organism was identified as a Helicobacter species that is most closely related to H. hepaticus. This bacterium is named Helicobacter trogontum. The type strain is strain LRB 8581 (= ATCC 700114).Spiral microorganisms were found in the stomachs of mamrnals as early as 1893 (1). However, the study of these bacteria gained momentum only after the description of a spiral bacterium in the gastric mucosa of humans and the demonstration that this organism is associated with gastric disease (20,21,33). This bacterium, Helicobacterpylori, was originally placed in the genus Campylobacter, but subsequently became the type species of a new genus, the genus Helicobacter, when it and Helicobacter mustelae were recognized as organisms that are only distantly related to campylobacters (10). Since then, 13 formally named species and at least six other species have been added to the genus Helicobacter. In addition to H. pylon, Helicobacter acinonyx (4), Helicobacter nemestrinae (2), Helicobacter felis (22), H. mustelae (7,22), and Helicobacter bizzozuonii (11) have been isolated from the stomachs of several mammalian species. Three "Gastrospirillum" species, gastric organisms which cannot currently be grown in pure culture, can be cultivated by passage in the stomachs of mice; these bacteria have been identified as members of the genus Helicohacter (16,19,27 In this paper we describe Helicobacter trogontum, a new Helicobacter species isolated from the intestinal mucosa of rats. MATERIALS AND METHODSSix strains of strongly urease-positive, gram-negative rods were isolated from the colonic mucosa of two Holtzman and four Wistar rats. Briefly, mucosal scrapings from the colons of these animals were streaked onto both Belo Horizonte medium (24) and brucella agar plates supplemented with trimethoprim, vancomycin, and polymyxin (Remel, Lenexa, Kans.) and incubated at 37°C in an atmosphere containing 90% nitrogen, 5% hydrogen, and 5% carbon dioxide.Biochemical characterization. Phenotypic tests commonly used to biotype campylobacters and helicobacters were performed to identify six strains. Plates were incubated under microaerobic conditions at 37°C for up to 7 days, unless otherwise stated. Growth at 25 and 42°C and under aerobic and anaerobic conditions was determined on sheep blood agar plates. Anaerobiosis was obtained with a GasPak jar and anaerobic generator envelopes (EEL, Cockeysvil...
The density of antral gastrin (G)- and somatostatin (D)-immunoreactive cells and the contents of antral gastrin and somatostatin were investigated in endoscopic antral biopsy specimens from patients with duodenal ulcer before and after eradication of Helicobacter pylori. After H. pylori eradication both antral somatostatin concentration (p = 0.0002) and antral D-cell density (p = 0.01) increased significantly. Conversely, although the number of G-cells was unchanged, antral (p = 0.0002) and serum (p = 0.001) gastrin contents decreased significantly. The number of oxyntic D-cells did not change significantly. These results strongly suggest that the hypergastrinaemia observed in H. pylori-positive patients may be due to a deficiency in antral somatostatin, which normally inhibits the synthesis and release of gastrin.
The [13 C]urea breath test ( 13 C-UBT) and Helicobacter pylori stool antigen test (HpSA) for the diagnosis of H. pylori infection in children were validated. The sensitivity, specificity, and positive and negative predictive values were 93.8, 99.1, 97.8, and 98.0%, respectively, for the 13 C-UBT and 96.9, 100, 100, and 98.0%, respectively, for HpSA. Both tests are appropriate for diagnosing H. pylori infection in children. The [13 C]urea breath test ( 13 C-UBT) and a new developed immunoassay for the detection of Helicobacter pylori antigens in stool, the H. pylori stool antigen test (HpSA) (3), are noninvasive tests for H. pylori diagnosis.Although the 13 C-UBT has a good sensitivity for the diagnosis of the infection in all ages, low specificity for very young children has been found (6). With respect to the stool test, low sensitivity for this age group has been also reported (2, 10). Thus, we aimed to validate the 13 C-UBT and HpSA for the diagnosis of H. pylori infection in children.We studied prospectively 210 consecutive children aged 1 to 18 years who underwent esophagogastroduodenoscopy for investigation of gastric complaints. This project was approved by the Ethics Committee of our institution.At endoscopy, biopsy specimens were obtained from the antral and oxyntic gastric mucosa for culture, urease test, and histology. Children were considered to be H. pylori positive if at least two of the three tests were positive or if the culture alone was positive. They were considered negative if all tests were negative.The 13 C-UBT was performed on fasting children within 1 week after endoscopy. The children received 200 ml of orange juice containing 75 mg of [ 13 C]urea (or 100 ml containing 50 mg for those Ͻ30 kg). Breath samples at baseline and after 30 min were analyzed with a nondispersive infrared spectrometer (NDIRIS; Wagner Analysen Technik, Bremen, Germany). The results were considered positive when delta over baseline (DOB) was Ͼ4.0‰.Stool samples, collected on the occasion of the endoscopy, were maintained at Ϫ20°C for up 1 year before testing. HpSA (Premier Platinum HpSA; Meridian Diagnostic, Cincinnati, Ohio) was performed according to the manufacturer's recommendation, slightly modified: instead of a stick, a 10-l disposable loop was used to dilute stool samples, as proposed by Oderda et al. (9), and the plates were washed exhaustively to remove unbound material.Among the 210 children enrolled, 167 underwent the 13 C-UBT but 6 children were excluded (4 had only one positive test and 2 had equivocal results in the 13 C-UBT). The remaining 161 children (76 boys; mean age, 8.6 Ϯ 3.8 years; range, 1 to 18 years) were included in the final analysis (48 were H. pylori positive and 15 had peptic ulcer). The 13 C-UBT was positive for 45 of 48 infected children and for one of the 113 noninfected ones (Table 1). The three children with false-negative 13 C-UBT results were a 5-year-old boy (DOB ϭ 0.3), a 9-yearold girl (DOB ϭ 0.5), and a 14-year-old girl (DOB ϭ 0.2). The cultures for all of them were positiv...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.