A fusiform bacterium with 3 to 14 multiple bipolar sheathed flagella and periplasmic fibers wrapped around the cell was isolated from the liver, bile, and lower intestine of aged, inbred mice. The bacteria grew at 37 and 42؇C under microaerophilic conditions, rapidly hydrolyzed urea, were catalase and oxidase positive, reduced nitrate to nitrite, did not hydrolyze indoxyl acetate or hippurate, and were resistant to both cephalothin and nalidixic acid but sensitive to metronidazole. On the basis of 16S rRNA gene sequence analysis, the organism was classified as a novel helicobacter, Helicobacter bilis. This new helicobacter, like Helicobacter hepaticus, colonizes the bile, liver, and intestine of mice. Although the organism is associated with multifocal chronic hepatitis, further studies are required to ascertain whether H. bilis is responsible for causing chronic hepatitis and/or hepatocellular tumors in mice.

Although infection with a cagA-positive Helicobacter pylori strain is considered a risk factor for the development of duodenal peptic ulcer in adults, this association has not been demonstrated in children. The presence of cagA was investigated by polymerase chain reaction in H. pylori strains isolated from 27 children with duodenal ulcer and 53 without duodenal ulcer. All patients (100%) with duodenal ulcer and 33 (62.3%) without ulcer were colonized by a cagA-positive strain (P=.00007). A cagA-positive status was also associated with a more marked macroscopic gastritis, with a greater inflammatory infiltrate of both mononuclear and polymorphonuclear cells in the antral and oxyntic gastric mucosae and degenerative and regenerative changes of the gastric mucosa. Increased cagA positivity was also associated with increased age, but no association between cagA-positive status and sex was observed.

Diarrhoeal disease is still considered a major cause of morbidity and mortality among children. Among diarrhoeagenic agents, Shigella should be highlighted due to its prevalence and the severity of the associated disease. Here, we assessed Shigella prevalence, drug susceptibility and virulence factors. Faeces from 157 children with diarrhoea who sought treatment at the Children's Hospital João Paulo II, a reference children´s hospital in Belo Horizonte, state of Minas Gerais, Brazil, were cultured and drug susceptibility of the Shigella isolates was determined by the disk diffusion technique. Shigella virulence markers were identified by polymerase chain reaction. The bacterium was recovered from 10.8% of the children (88.2% Shigella sonnei). The ipaH, iuc, sen and ial genes were detected in strains isolated from all shigellosis patients; set1A was only detected in Shigella flexneri. Additionally, patients were infected by Shigella strains of different ial, sat, sen and set1A genotypes. Compared to previous studies, we observed a marked shift in the distribution of species from S. flexneri to S. sonnei and high rates of trimethoprim/sulfamethoxazole resistance.

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...

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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.

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' Flexispira rappini ' is a provisional name given to Gram-negative, microaerophilic, motile, spindle-shaped micro-organisms with spiral periplasmic fibres and bipolar tufts of sheathed flagella. Several investigators, including Kirkbride, Romero, and Archer isolated strains possessing this morphology. Previously, the phylogenetic position of three ' Flexispira rappini ' strains was determined by 16S rRNA sequencing, which indicated that flexispira were members of the genus Helicobacter. As more organisms with ' F. rappini ' morphology were isolated, it became apparent that there were multiple Helicobacter taxa with this distinctive morphology. The purpose of this study was to examine a collection of 36 ' F. rappini ' strains from diverse habitats by using 16S rRNA sequence analysis. The strains fell into 10 taxa, each possibly representing a novel Helicobacter species. Two of these flexispira taxa were previously named, by us, Helicobacter bilis and Helicobacter trogontum. Currently, none of the flexispira taxa contains enough phenotypically and genotypically characterized strains to be formally named ' Helicobacter rappinii '.