Profiling and Identification of Eubacteria in the Stomach of Mongolian Gerbils With and Without <i>Helicobacter pylori</i> Infection

Sun, Yi‐Qian; Monstein, Hans‐Jürg; Nilsson, Lennart; Petersson, Fredrik; Borch, Kurt

doi:10.1046/j.1523-5378.2003.00136.x

Cited by 32 publications

(33 citation statements)

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“…Preliminary results from culture of stomach homogenates and generation of 16S rRNA gene clone libraries from naïve mice confirmed that the murine stomach was highly colonized by lactobacilli, with the dominant species being Lactobacillus reuteri and Lactobacillus murinus (supplementary data), which is consistent with other studies (1,2,10,12). In addition, T-RFLP data from an initial short-term H. pylori infection experiment with the SS1 strain (6) indicated that the gastric microbiotas of H. pylori-infected mice were similar to those of age-matched naïve mice, implying that an acute H. pylori in- fection does not significantly affect the gastric microbiota (supplementary data).…”

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confidence: 90%

“…Various animal models are currently used to study the pathogenesis of H. pylori infection, but there is little information on the gastric bacterial composition of rodents after H. pylori infection (1,2,7,12). We therefore compared the gastric flora compositions, over time, of uninfected mice and of mice infected with H. pylori using conventional culture methods and terminal-restriction fragment length polymorphism (T-RFLP) analysis.…”

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confidence: 99%

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Chronic Helicobacter pylori Infection Does Not Significantly Alter the Microbiota of the Murine Stomach

Tan

Kaparakis²,

Galić³

et al. 2007

Appl Environ Microbiol

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We examined the impact of Helicobacter pylori infection on the murine gastric microbiota by culture and terminal-restriction fragment length polymorphism and found that neither acute nor chronic H. pylori infection substantially affected the gastric microbial composition. Interestingly, the total H. pylori burden detected by real-time PCR was significantly higher than that revealed by viable counts, suggesting that the antigenic load sustaining H. pylori-induced gastritis could be considerably higher than previously believed.Helicobacter pylori colonizes the stomachs of an estimated 50% of the world's population and is classified as a group 1 carcinogen (4, 15). Various animal models are currently used to study the pathogenesis of H. pylori infection, but there is little information on the gastric bacterial composition of rodents after H. pylori infection (1, 2, 7, 12). We therefore compared the gastric flora compositions, over time, of uninfected mice and of mice infected with H. pylori using conventional culture methods and terminal-restriction fragment length polymorphism (T-RFLP) analysis.Six-to 8-week-old female C57BL/6 mice were reared under specific-pathogen-free conditions at the animal facility of the Department of Microbiology and Immunology, University of Melbourne. All animal experiments were approved by the University of Melbourne Animal Ethics and Experimental Committee and complied with relevant legislation. Statistical significance was assessed by the nonparametric Mann-Whitney U test, and two-tailed P values of less than 0.05 were considered statistically significant.Preliminary results from culture of stomach homogenates and generation of 16S rRNA gene clone libraries from naïve mice confirmed that the murine stomach was highly colonized by lactobacilli, with the dominant species being Lactobacillus reuteri and Lactobacillus murinus (supplementary data), which is consistent with other studies (1, 2, 10, 12). In addition, T-RFLP data from an initial short-term H. pylori infection experiment with the SS1 strain (6) indicated that the gastric microbiotas of H. pylori-infected mice were similar to those of age-matched naïve mice, implying that an acute H. pylori in-* Corresponding author. Mailing address:

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confidence: 90%

mentioning

confidence: 99%

Chronic Helicobacter pylori Infection Does Not Significantly Alter the Microbiota of the Murine Stomach

Tan

Kaparakis²,

Galić³

et al. 2007

Appl Environ Microbiol

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“…In the present study, all three strains had been passaged in vitro multiple times before they were used for the first inoculation. Indigenous bacteria may also have an impact on the colonization and growth of H. pylori strains in the stomach of Mongolian gerbils (Sun et al 2003). In this study, bacteria other than H. pylori were not specifically determined in the stomach.…”

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confidence: 74%

Multiple in vivo passages enhance the ability of a clinical Helicobacter pylori isolate to colonize the stomach of Mongolian gerbils and to induce gastritis

Bleich¹,

Kohn²,

Glage³

et al. 2005

Lab Anim

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SummaryThe Mongolian gerbil is an excellent animal model for Helicobacter pylori-induced gastritis in humans. In this study, initially low colonization rates of the H. pylori strains ATCC 43504, SS1, or HP87 inoculated into gerbils caused difficulties in establishing this model. In order to increase the colonization ability and pathogenicity, the clinical HP87 isolate was selected for adaptation to the gerbil stomach by multiple in vivo passages through gerbils. Development of gastritis was examined histologically at 4-52 weeks after infection. The proportion of gerbils which tested positive for H. pylori by culture at four weeks after inoculation gradually increased from 11.1% of gerbils inoculated with HP87 without prior in vivo passage (P0) to 100% of gerbils inoculated with HP87 with seven in vivo passages (P7). In addition, adaptation of HP87 resulted in more severe histopathological changes. Gerbils infected with adapted HP87 (P7) exhibited severe infiltration by monomorphonuclear and polymorphonuclear leukocytes in the mucosa, submucosa, and subserosa of the gastric antrum, as well as epithelial changes consisting of hyperplasia, erosion, and ulceration. Histopathological changes increased in severity from four to 52 weeks after infection. Adaptation of HP87 during its passages through gerbils could be due to genetic changes in bacterial colonization factors. Identification of these changes might be useful to understand the underlying mechanism of gastric adaptation and pathogenesis of H. pylori.

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“…Lactobacillus is rarely detected in patients with gastric pH of 3 or less (6). Animal studies have shown that indigenous lactobacilli have an inhibitory impact on H. pylori colonization (36). If the resident microflora does have a role in the defense against infection, synergistic relations between multiple members of the normal flora, rather than a single species, may be more important in suppressing the growth and colonization of potential pathogens (37).…”

Section: Discussionmentioning

confidence: 99%

Non-Helicobacter Bacterial Flora Rarely Develops in the Gastric Mucosal Layer of Children

Kato

Fujimura

Kimura³

et al. 2006

Dig Dis Sci

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Non-Helicobacter bacteria can be cultured from the gastric mucosa in adults but in children, there are no studies about such microflora. The purpose of this study, therefore, was to clarify whether gastric biota develops in children. In 10 children and 10 adults or elderly (5 H. pylori-infected and 5 uninfected in each group), biopsy specimens of the gastric antrum and corpus and gastric juice were studied for bacterial examinations and the data were compared between both age groups in relation to H. pylori status and luminal pH. Bacterial genera and species were analyzed using both culture and real-time polymerase chain reaction (PCR) with the 52 genus- and species-specific primer sets. Non-Helicobacter bacteria in the mucosa were cultured from all adult patients, whereas microorganisms were cultured in only one child (p < .001). Gastric pH was lower in children (median, 1.4) than in adults (median, 2.6) (p < .005). The grade of endoscopic gastric atrophy was moderate or severe in 8 adults, but absent or mild in all 10 children. Among adults, there was a significant positive correlation between gastric pH and total bacterial counts of both the mucosa and juice. These data indicate that impaired gastric acid secretion associated with long-term H. pylori infection enables non-Helicobacter bacteria to colonize in the human stomach. Such microorganisms rarely colonize in the gastric mucosa in children regardless of H. pylori status.

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Profiling and Identification of Eubacteria in the Stomach of Mongolian Gerbils With and Without Helicobacter pylori Infection

Abstract: These findings suggest that indigenous bacteria, particularly lactobacilli, may have an impact on the colonization and growth of H. pylori strains in the stomach of Mongolian gerbils.

Cited by 32 publications

References 43 publications

Chronic Helicobacter pylori Infection Does Not Significantly Alter the Microbiota of the Murine Stomach

Chronic Helicobacter pylori Infection Does Not Significantly Alter the Microbiota of the Murine Stomach

Multiple in vivo passages enhance the ability of a clinical Helicobacter pylori isolate to colonize the stomach of Mongolian gerbils and to induce gastritis

Non-Helicobacter Bacterial Flora Rarely Develops in the Gastric Mucosal Layer of Children

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