Gastric Campylobacter-like Organisms Research Articles

Comparison of Partial 16S rRNA Sequences of Different Helicobacter pylori Strains, Helicobacter mustelae and a Gastric Campylobacter-like Organism (GCLO)

Partial 16S rRNA sequences of seven Helicobacter pylori strains from three different continents were compared. High homogeneity (99.5%–100%) of 16S rRNA between H. pylori strains was demonstrated, when a 397 nucleotides long stretch of RNA was compared. The obtained consensus sequence was practically identical with one of the two published sequences, 99.4% similarity ( Romaniuk et al., J. Bact. 169 , 2137–2141 (1987)), whereas with the other published sequence the identity was lower, 95.8% similarity ( Thompson et al., Int. J. System. Bact. 38 , 190–200 (1988)). Comparison of the consensus H. pylori sequence with the sequence of Helicobacter mustelae , the spiral organism isolated from ferrets, revealed 93.8% similarity. H. mustelae was also compared with published sequences of Wollinella succinogenes , and Campylobacter jejuni . The percentual sequence similarities were 96.0 and 83.7, respectively. A gastric campylobacter-like organism (GCLO, NCTC 11847), isolated from the gastric antrum has been demonstrated to resemble C. jejuni biochemically. By 16S rRNA sequences we demonstrate that the GCLO is in fact a C. jejuni strain.

Proteolytic activities of human Campylobacter pylori and ferret gastric Campylobacter-like organism

The levels of proteolytic activity in cell washes, lysates and pellets of C. pylori and gastric Campylobacter-like organisms isolated from humans and ferrets, respectively, have been studied using porcine mucus glycoprotein and bovine haemoglobin substrates. The total haemoglobin degrading activity, expressed by 10 12–10 13 cfu of either organism, was no greater than 3μg chymotrypsin equivalents. The mucolytic specific activity (rate of mucus peptide bond hydrolysis by bacterial protein) of the fractions tested from both organisms did not exceed 2nmol/min/mg protein. This value is 1000-fold lower than expected from published data. Electrophoretic profiles suggested that the mucolytic activity assessed by fluorimetry was insufficient to alter the quaternary structure of mucus and hence may not significantly contribute to the undermining of gastric mucus integrity.

Isoelectric focusing of ureases from Campylobacter pylori and related organisms

Agarose gel isoelectric focusing was used to determine the isoelectric points of ureases from strains of gastric campylobacterlike organisms isolated from ferrets (pI 5.4), baboons (pI 5.7), and pigs (pI 5.9) and from isolates of Campylobacter pylori in humans (pI 5.9). This technique may help differentiate these closely related bacteria.

The characterization and pathological significance of gastric Campylobacter-like organisms in the ferret: a model for chronic gastritis?

Gastric campylobacter-like organisms (CLO) were isolated from gastric tissues removed at sacrifice from 17 mature ferrets; all animals were colonized, but no macroscopic mucosal lesions or histological features of chronic gastritis were seen. The isolates resembled Campylobacter pylori in many cultural and biochemical characteristics, and produced substantial urease activity, but there were sufficient differences from C. pylori to suggest that ferret gastric CLO represents a separate species. Comparison of human C. pylori and ferret gastric CLO may help to elucidate the pathogenicity of the former in patients with gastritis, and the ferret may serve as a useful animal model for the study of C. pylori infection.

Two urease activities with different pH optima in Campylobacter pylori and similar organisms

The urease activity of Campylobacter pylori was measured over a range of pH values. In a citrate-Hepes system, two peaks of activity were seen, at pH 5 and at pH 8. The former activity was inhibited by phosphate. Gastric campylobacter-like organisms isolated from the stomachs of several mammals resembled C. pylori in possessing two urease activities with different pH optima.

Naturally occurring chronic gastritis and C pylori infection in the rhesus monkey: a potential model for gastritis in man.

Histological examination of the stomachs of Rhesus monkeys at autopsy showed chronic gastritis in a high proportion of all ages. Lesions consisted of mild to heavy infiltration of the lamina propria by lymphocytes, plasma cells, and histiocytes. The antrum was most consistently affected, but lesions were also present in the fundus and pylorus. Gastric Campylobacter-like organisms (GCLO) apparently identical to human C pylori were cultured and/or detected immunohistologically in several animals. Electron microscopy showed the spiral bacteria on the epithelial surface and in gastric pits. They did not penetrate the cells but were intimately attached to the apical plasma membrane and caused loss of microvilli. Antibodies to C pylori were detected in serum of the monkeys by ELISA. The immunospecificity of this antibody response was confirmed by Western blotting techniques. A small number of cynomolgus monkeys examined had gastritis, which may also be associated with the presence of C pylori. Baboons did not have gastritis, nor was C pylori cultured from their stomachs. The study indicates that the Rhesus monkey has a naturally occurring gastritis associated with C pylori infection and may therefore be a suitable experimental animal for the human disease.

Gastritis and gastric campylobacter-like organisms in patients without peptic ulcer.

Gastric biopsy specimens were obtained from 83 patients without peptic ulcer disease and analysed histologically. Culture and serological studies were done on the last 64 patients. The patients were divided into two age groups (young and old groups.) In 34 patients with chronic superficial gastritis, gastric campylobacter-like organisms (GLCO) were identified histologically in 91% and grown on culture in 88%: antibody to GCLO was detected in 81%. No age-related difference in the prevalence of the organism was demonstrated. In the 23 patients with atrophic gastritis (all elderly), presence of the organisms appeared to be related to the presence of an inflammatory cell infiltrate into the gastric mucosa. These figures for the prevalence of the organism in this selected group of patients are similar to those reported in previous studies of unselected patients which included those with peptic ulcer. This suggests that GCLO is unlikely to be causally related to peptic ulcer.

Identification of the outer membrane proteins of Campylobacter pyloridis and antigenic cross-reactivity between C. pyloridis and C. jejuni.

The outer membrane and surface exposed proteins of four strains of the gastric Campylobacter-like organism Campylobacter pyloridis were identified by SDS-PAGE of Sarkosyl-insoluble membranous material and 125I-surface-labelled whole bacteria. Although constant outer membrane proteins (molecular mass 61, 54 and 31 kDa) were observed in these strains, several variable 125I-labelled surface proteins were detected. C. pyloridis does not appear to express a single surface-exposed major outer membrane protein like that of C. jejuni and C. coli. Putative flagella proteins were identified from isolated flagella and acid-extractable surface material and by immunoblotting with anti-flagella antibodies. Several major protein antigens were observed by immunoblotting with anti-C. pyloridis antisera. At least two of these antigens cross-reacted with anti-C. jejuni antiserum. This cross-reaction appears to be caused primarily by flagellar antigens. However, one major protein antigen (61 kDa) was not cross-reactive with C. jejuni and may, therefore, be useful in serological tests for the specific diagnosis of C. pyloridis infections.

Antibody to the gastric campylobacter-like organism ("Campylobacter pyloridis")--clinical correlations and distribution in the normal population.

Different cellular proteins of the gastric campylobacter-like organism (GCLO) were shown to be immunogenic for man. Antibodies to GCLO were detected in sera by both complement fixation and enzyme-linked immunoabsorbent assay. Antibody was found in 133 (52%) of 254 patients attending for gastroscopy. There was a high correlation between presence of antibody and a positive GCLO culture from the gastric mucus. Patients with normal endoscopic appearances, duodenal ulcer, duodenitis and oesophagitis had similar prevalences (c. 50%) of antibody. Only patients with endoscopically visible gastritis or gastric ulcer had a higher frequency (c. 80%) of antibody. In a normal population, antibody was uncommon in individuals less than 20 years old, but the prevalence of antibody increased (to c. 50%) with age. There was little evidence to support an important pathological role for GCLO in disorders of the upper gastrointestinal tract, although the possibility that it may be a co-factor in the pathogenesis of gastric ulcer cannot be excluded.

An ultrastructural study of the gastric campylobacter-like organism 'Campylobacter pyloridis'.

Microaerophilic spiral organisms may be isolated frequently from samples of gastric mucus taken from patients undergoing gastroscopy. The ultrastructure of these gastric campylobacter-like organisms ('Campylobacter pyloridis') shows that they have greater affinities with Spirillum than with Campylobacter.

The use of picolinyl esters for the characterization of microbial lipids: application to the unsaturated and cyclopropane fatty acids of campylobacter species

Picolinyl esters have been recently introduced for the mass spectrometric structure determination of unsaturated and cyclopropane fatty acids. We have used these derivatives to characterize the unsaturated and cyclopropane acids of Campylobacter species. The principle unsaturated acids were shown to be 11-octadecenoic acid, with smaller amounts of 9-hexadecenoic acid, 9-octadecenoic acid and 9, 11-octadecadienoic acid. The only cyclopropane acid present was cis 11, 12-methylene octadecanoic acid. There was no interspecific variation in the position of unsatu-ration or methylene bridges, even in the recently discovered gastric Campylobacter like organisms (GCLO) or the urease positive thermophilic Campylobacters (UPTC), the fatty acid profiles of which were consistent with their inclusion in the genus Campylobacter.