Helicobacter pylori colonization critically depends on postprandial gastric conditions

High gastrointestinal digestive stability endows chondroitin sulfate-soluble undenatured type II collagen complex with high activity: Improvement of osteoarthritis in rats

Previously, we prepared a chondroitin sulfate-soluble undenatured type II collagen complex (CS-SC II) with low salt content. This paper further explored the differences between CS-SC II and SC II in terms of gastrointestinal digestive characteristics and osteoarthritis (OA) improvement. In vitro and in vivo experiments showed that the gastric digestive stability of CS-SC II was high under both pH 2.0 and pH 3.0, the α1 chain and triple helix structure of type II collagen retained >60 %. However, SC II had high gastric digestive stability only under pH 3.0. Furthermore, intestinal digestion had little effect on α1 chains of CS-SC II and SC II, and distribution experiments showed that they might exert their biological activities in the intestine. CS-SC II had obvious improvement in OA rats at 1.0 mg/kg/d, that is, the joint swelling was significantly reduced and the weight-bearing ratio of the right hind limb was increased to 49 %, which was close to that of 4.0 mg/kg/d SC II. The wear of articular cartilage, Mankin and OARSI scores of rats in CS-SC II group were significantly reduced. The effects of low-dose CS-SC II on the proportion of regulatory T cells (Treg), mRNA expression of OA key biomarkers (Il6, Ccl7, MMP-3 and MMP13) and signaling pathway genes (NF-κB, AKT or AMPKα) were comparable to those of high-dose SC II. These results showed that CS-SC II might have greater potential to improve OA at a lower dose than SC II due to its high gastrointestinal digestive stability at a wide range of pH conditions.

Helicobacter pylori intragastric colonization and migration: Endoscopic manifestations and potential mechanisms

After being ingested and entering the human stomach, Helicobacter pylori (H. pylori) adopts several effective strategies to adhere to and colonize the gastric mucosa and move to different regions of the stomach to obtain more nutrients and escape from the harsher environments of the stomach, leading to acute infection and chronic gastritis, which is the basis of malignant gastric tumors. The endoscopic manifestations and pathological features of H. pylori infection are diverse and vary with the duration of infection. In this review, we describe the endoscopic manifestations of each stage of H. pylori gastritis and then reveal the potential mechanisms of bacterial intragastric colonization and migration from the perspective of endoscopists to provide direction for future research on the effective therapy and management of H. pylori infection.

Evolved to vary: genome and epigenome variation in the human pathogen Helicobacter pylori

Helicobacter pylori is a Gram-negative, spiral shaped bacterium that selectively and chronically infects the gastric mucosa of humans. The clinical course of this infection can range from lifelong asymptomatic infection to severe disease, including peptic ulcers or gastric cancer. The high mutation rate and natural competence typical of this species are responsible for massive inter-strain genetic variation exceeding that observed in all other bacterial human pathogens. The adaptive value of such a plastic genome is thought to derive from a rapid exploration of the fitness landscape resulting in fast adaptation to the changing conditions of the gastric environment. Nevertheless, diversity is also lost through recurrent bottlenecks and H. pylori's lifestyle is thus a perpetual race to maintain an appropriate pool of standing genetic variation able to withstand selection events. Another aspect of H. pylori's diversity is a large and variable repertoire of restriction-modification systems. While not yet completely understood, methylome evolution could generate enough transcriptomic variation to provide another intricate layer of adaptive potential. This review provides an up to date synopsis of this rapidly emerging area of H. pylori research that has been enabled by the ever-increasing throughput of Omics technologies and a multitude of other technological advances.

Helicobacter pylori infection and micronutrient deficiency in pregnant women: a systematic review and meta-analysis

Background

Over the last few years, epidemiological studies have shown that infection with Helicobacter pylori has a major effect on micronutrient deficiency as well as on adverse pregnancy outcomes. Importantly, there are gaps in understanding the linkage of H. pylori infection with micronutrients deficiency in pregnant women.

Objective

We conducted a systematic review and meta-analysis to estimate the association between H. pylori infection and micronutrient deficiencies in pregnant women.

Methods

A systematic literature search was conducted for relevant articles using PubMed, Web of Science, and Scopus database from inception to March 2020. The OR with 95% CIs was determined by meta-analysis of data extracted from the selected studies.

Results

From 2384 primary articles, 6 studies were selected for systematic reviews and 4 studies distinctively (with 1274 participants: 553 cases and 721 controls) were selected for meta-analysis. The meta-analysed fixed effect model estimated the odds of having H. pylori infection was not significantly higher among pregnant women with micronutrient deficiencies than those without deficiencies (OR=1.12, 95% CI 0.88 to 1.42, p=0.37). In the subgroup analysis, no correlation was found between H. pylori infection and vitamin B₁₂ (OR=0.74, 95% CI 0.45 to 1.21, p=0.22), folate (OR=1.07, 95% CI 0.73 to 1.58, p=0.73), and ferritin (OR=0.81, 95% CI 0.51 to 1.31, p=0.4). However, a positive correlation was found between iron-deficiency anaemia (IDA) and H. pylori infection (OR=16.23, 95% CI 4.19 to 62.93, p<0.0001) during pregnancy.

Conclusion

H. pylori infection is associated with increased risk of IDA but not with deficiency of other micronutrients in pregnancy.

PROSPERO registration number

CRD42019135683.

Protein solubility, secondary structure and microstructure changes in two types of undenatured type II collagen under different gastrointestinal digestion conditions

Sodium dodecyl sulfonate polyacrylamide gel electrophoresis (SDS-PAGE), circular dichroism spectroscopy (CD), transmission electron microscope (TEM) and atomic force microscope (AFM) were used to analyze the structural properties and gastrointestinal digestive characteristics of natural insoluble undenatured type II collagen (IC II) and pepsin soluble undenatured type II collagen (SC II). Results showed that, after gastric digestion, especially under low pH conditions, some thick and short collagen fibers were dissolved from IC II, which was accompanied by the release of soluble protein with triple helix structure. As to SC II, when gastric digestion was performed under higher pH conditions, collagen fibers were mildly thinned and curved, and the triple helix structure was slightly destroyed. However, those changes hardly occurred during the intestinal digestion. Moreover, the undenatured type II collagen existing in SC II digestive supernatant was 1.2-12.4 times higher than that of IC II depending on the pH conditions. These results suggested that, it is more likely for SC II to exert its activity of relieving arthritis, and it should be taken when the pH of gastric environment is high.

Within-host evolution of Helicobacter pylori shaped by niche-specific adaptation, intragastric migrations and selective sweeps

The human pathogen Helicobacter pylori displays extensive genetic diversity. While H. pylori is known to evolve during infection, population dynamics inside the gastric environment have not been extensively investigated. Here we obtained gastric biopsies from multiple stomach regions of 16 H. pylori-infected adults, and analyze the genomes of 10 H. pylori isolates from each biopsy. Phylogenetic analyses suggest location-specific evolution and bacterial migration between gastric regions. Migration is significantly more frequent between the corpus and the fundus than with the antrum, suggesting that physiological differences between antral and oxyntic mucosa contribute to spatial partitioning of H. pylori populations. Associations between H. pylori gene polymorphisms and stomach niches suggest that chemotaxis, regulatory functions and outer membrane proteins contribute to specific adaptation to the antral and oxyntic mucosa. Moreover, we show that antibiotics can induce severe population bottlenecks and likely play a role in shaping the population structure of H. pylori.

Helicobacter pylori-induced gastric pathology: insights from in vivo and ex vivo models

Gastric colonization with Helicobacter pylori induces diverse human pathological conditions, including superficial gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric adenocarcinoma and its precursors. The treatment of these conditions often relies on the eradication of H. pylori, an intervention that is increasingly difficult to achieve and that does not prevent disease progression in some contexts. There is, therefore, a pressing need to develop new experimental models of H. pylori-associated gastric pathology to support novel drug development in this field. Here, we review the current status of in vivo and ex vivo models of gastric H. pylori colonization, and of Helicobacter-induced gastric pathology, focusing on models of gastric pathology induced by H. pylori, Helicobacter felis and Helicobacter suis in rodents and large animals. We also discuss the more recent development of gastric organoid cultures from murine and human gastric tissue, as well as from human pluripotent stem cells, and the outcomes of H. pylori infection in these systems.

Gastrointestinal Tract As Entry Route for Hantavirus Infection

Background: Hantaviruses are zoonotic agents that cause hemorrhagic fevers and are thought to be transmitted to humans by exposure to aerosolized excreta of infected rodents. Puumala virus (PUUV) is the predominant endemic hantavirus in Europe. A large proportion of PUUV-infected patients suffer from gastrointestinal symptoms of unclear origin. In this study we demonstrate that PUUV infection can occur via the alimentary tract. Methods: We investigated susceptibility of the human small intestinal epithelium for PUUV infection and analyzed the resistance of virions to gastric juice. As model for intestinal virus translocation we performed infection experiments with human intestinal Caco-2 monolayers. In animal experiments we infected Syrian hamsters with PUUV via the intragastric route and tested seroconversion and protective immunity against subsequent Andes virus challenge. Results: PUUV retained infectivity in gastric juice at pH >3. The virus invaded Caco-2 monolayers in association with endosomal antigen EEA1, followed by virus replication and loss of epithelial barrier function with basolateral virus occurrence. Cellular disturbance and depletion of the tight junction protein ZO-1 appeared after prolonged infection, leading to paracellular leakage (leak flux diarrhea). Moreover, animal experiments led to dose-dependent seroconversion and protection against lethal Andes virus challenge. Conclusions: We provide evidence that hantavirus can infect the organism via the alimentary tract and suggest a novel aspect of hantavirus infection and pathogenesis. Significance: Hantaviruses are zoonotic pathogens causing severe hemorrhagic fevers worldwide. They are transmitted to humans by small mammals. To date, these viruses were thought to infect exclusively through the airborne route by inhalation of aerosols from infectious animal droppings or by rodent bites. In our work we could show that the alimentary tract is an alternative path of infection for hantaviruses, meaning a new association of virus and disease. These findings have impact on current textbook knowledge and bring many implications for hantavirus epidemiology and outbreak prevention measures.

Early apoptosis of monocytes induced by Helicobacter pylori infection through multiple pathways

Only a small percentage of people infected with Helicobacter pylori (H. pylori) will develop overt chronic gastric diseases. To understand the pathological mechanism, the action of H. pylori on monocyte apoptosis was detected. H. pylori co-culturing with peripheral blood monocytes, THP-1 or U937 cells result in early apoptosis at 6, 12, and 24 h after infection. The phosphorylated Bad and JNK were increased, and Bcl-2 was declined at 6, 12, and 24 h in peripheral blood monocytes after H. pylori infection. The phosphorylated Akt was augmented at 6 and 12 h post-infection. A slow apoptotic response was induced by H. pylori via Bad and Bcl-2 regulators, activated caspase-8 and caspase-9, and JNK at 24 h in THP-1 cells. Meanwhile, only Bad and JNK were involved in regulating U937 cells apoptosis at 24 h after infection. These results supported a novel mechanism of H. pylori escaping from monocytes by upregulation of early apoptosis and inhibition of late apoptosis. The differences among the three cells may reveal why H. pylori-derived disease occurs in relatively few people and provide a pathological mechanism whereby a treatment for H. pylori-derived disease may be developed.

Helicobacter pylori modulates host cell responses by CagT4SS-dependent translocation of an intermediate metabolite of LPS inner core heptose biosynthesis

Highly virulent Helicobacter pylori cause proinflammatory signaling inducing the transcriptional activation and secretion of cytokines such as IL-8 in epithelial cells. Responsible in part for this signaling is the cag pathogenicity island (cagPAI) that codetermines the risk for pathological sequelae of an H. pylori infection such as gastric cancer. The Cag type IV secretion system (CagT4SS), encoded on the cagPAI, can translocate various molecules into cells, the effector protein CagA, peptidoglycan metabolites and DNA. Although these transported molecules are known to contribute to cellular responses to some extent, a major part of the cagPAI-induced signaling leading to IL-8 secretion remains unexplained. We report here that biosynthesis of heptose-1,7-bisphosphate (HBP), an important intermediate metabolite of LPS inner heptose core, contributes in a major way to the H. pylori cagPAI-dependent induction of proinflammatory signaling and IL-8 secretion in human epithelial cells. Mutants defective in the genes required for synthesis of HBP exhibited a more than 95% reduction of IL-8 induction and impaired CagT4SS-dependent cellular signaling. The loss of HBP biosynthesis did not abolish the ability to translocate CagA. The human cellular adaptor TIFA, which was described before to mediate HBP-dependent activity in other Gram-negative bacteria, was crucial in the cagPAI- and HBP pathway-induced responses by H. pylori in different cell types. The active metabolite was present in H. pylori lysates but not enriched in bacterial supernatants. These novel results advance our mechanistic understanding of H. pylori cagPAI-dependent signaling mediated by intracellular pattern recognition receptors. They will also allow to better dissect immunomodulatory activities by H. pylori and to improve the possibilities of intervention in cagPAI- and inflammation-driven cancerogenesis.

The Cag Type IV secretion system, which contributes to inflammation and cancerogenesis during chronic infection, is one of the major virulence and fitness factors of the bacterial gastric pathogen Helicobacter pylori. Up to now, the mechanisms leading to cagPAI-dependent signal transduction and cytokine secretion were not completely understood. We report here that HBP, an intermediate metabolite in LPS core heptose biosynthesis, is translocated into host cells dependent on the CagT4SS, and is a major factor leading to the activation of cellular responses. This response is connected to the human cellular adaptor protein TIFA. The knowledge of this specific response pathway is a major advance in understanding CagT4SS-dependent signaling and will enable us to understand better how H. pylori modulates the immune response repertoire in its human host.

Accuracy of testing for anti-Helicobacter pylori IgG in urine for H. pylori infection diagnosis: a systematic review and meta-analysis

OBJECTIVES

This meta-analysis aims to systematically measure the potential diagnostic value of anti-Helicobacter pylori IgG in urine for infection diagnosis, using all eligible studies published in English and Chinese languages.

DESIGN

The random effect model was used to analyse the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative LR (NLR), diagnostic OR (DOR), together with the summary receiver operator characteristic curve.

SETTING

Literature searches of databases including PubMed, EMBASE, MEDLINE, Web of Science, Chinese National Knowledge Infrastructure and Wanfang databases were performed to retrieve studies evaluating the diagnostic value of urine IgG antibody for H.pylori infection.

PRIMARY OUTCOME MEASURE

Twenty-three studies with 4963 subjects were included in the current meta-analysis.

RESULTS

The pooled sensitivity, specificity, PLR, NLR, DOR and area under the curve (AUC) were 0.83 (95% CI 0.82 to 0.85), 0.89 (95% CI 0.88 to 0.90), 8.81 (95% CI 6.37 to 12.2), 0.13 (95% CI 0.09 to 0.2), 73 (95% CI 46.45 to 114.74) and 0.9551, respectively. Subgroup analyses showed that diagnostic accuracy of the urine IgG assay was no different in age, region, study population and assay method.

CONCLUSIONS

Anti-H. pylori antibody in urine might serve as a good marker in diagnosing H. pylori infection. However, further validation based on a larger sample is still required.

Localisation and protein-protein interactions of the Helicobacter pylori taxis sensor TlpD and their connection to metabolic functions

The Helicobacter pylori energy sensor TlpD determines tactic behaviour under low energy conditions and is important in vivo. We explored protein-protein interactions of TlpD and their impact on TlpD localisation and function. Pull-down of tagged TlpD identified protein interaction partners of TlpD, which included the chemotaxis histidine kinase CheAY2, the central metabolic enzyme aconitase (AcnB) and the detoxifying enzyme catalase (KatA). We confirmed that KatA and AcnB physically interact with TlpD. While the TlpD-dependent behavioural response appeared not influenced in the interactor mutants katA and acnB in steady-state behavioural assays, acetone carboxylase subunit (acxC) mutant behaviour was altered. TlpD was localised in a bipolar subcellular pattern in media of high energy. We observed a significant change in TlpD localisation towards the cell body in cheAY2-, catalase- or aconitase-deficient bacteria or in bacteria incubated under low energy conditions, including oxidative stress or respiratory inhibition. Inactivation of tlpD resulted in an increased sensitivity to iron limitation and oxidative stress and influenced the H. pylori transcriptome. Oxidative stress, iron limitation and overexpressing the iron-sulfur repair system nifSU altered TlpD-dependent behaviour. We propose that TlpD localisation is instructed by metabolic activity and protein interactions, and its sensory activity is linked to iron-sulfur cluster integrity.

Towards Fluorescence In Vivo Hybridization (FIVH) Detection of H. pylori in Gastric Mucosa Using Advanced LNA Probes

In recent years, there have been several attempts to improve the diagnosis of infection caused by Helicobacter pylori. Fluorescence in situ hybridization (FISH) is a commonly used technique to detect H. pylori infection but it requires biopsies from the stomach. Thus, the development of an in vivo FISH-based method (FIVH) that directly detects and allows the visualization of the bacterium within the human body would significantly reduce the time of analysis, allowing the diagnosis to be performed during endoscopy. In a previous study we designed and synthesized a phosphorothioate locked nucleic acid (LNA)/ 2’ O-methyl RNA (2’OMe) probe using standard phosphoramidite chemistry and FISH hybridization was then successfully performed both on adhered and suspended bacteria at 37°C. In this work we simplified, shortened and adapted FISH to work at gastric pH values, meaning that the hybridization step now takes only 30 minutes and, in addition to the buffer, uses only urea and probe at non-toxic concentrations. Importantly, the sensitivity and specificity of the FISH method was maintained in the range of conditions tested, even at low stringency conditions (e.g., low pH). In conclusion, this methodology is a promising approach that might be used in vivo in the future in combination with a confocal laser endomicroscope for H. pylori visualization.

Dynamics of Lewis b binding and sequence variation of the babA adhesin gene during chronic Helicobacter pylori infection in humans

Helicobacter pylori undergoes rapid microevolution during chronic infection, but very little is known about how this affects host interaction factors. The best-studied adhesin of H. pylori is BabA, which mediates binding to the blood group antigen Lewis b [Le(b)]. To study the dynamics of Le(b) adherence during human infection, we analyzed paired H. pylori isolates obtained sequentially from chronically infected individuals. A complete loss or significant reduction of Le(b) binding was observed in strains from 5 out of 23 individuals, indicating that the Le(b) binding phenotype is quite stable during chronic human infection. Sequence comparisons of babA identified differences due to mutation and/or recombination in 12 out of 16 strain pairs analyzed. Most amino acid changes were found in the putative N-terminal extracellular adhesion domain. One strain pair that had changed from a Le(b) binding to a nonbinding phenotype was used to study the role of distinct sequence changes in Le(b) binding. By transformations of the nonbinding strain with a babA gene amplified from the binding strain, H. pylori strains with mosaic babA genes were generated. Recombinants were enriched for a gain of Le(b) binding by biopanning or for BabA expression on the bacterial surface by pulldown assay. With this approach, we identified several amino acid residues affecting the strength of Le(b) binding. Additionally, the data showed that the C terminus of BabA, which is predicted to encode an outer membrane β-barrel domain, plays an essential role in the biogenesis of this protein.

Helicobacter pylori causes a chronic infection of the human stomach that can lead to ulcers and cancer. The bacterium can bind to gastric epithelial cells with specialized outer membrane proteins. The best-studied protein is the BabA adhesin which binds to the Lewis b blood group antigen. Since H. pylori is a bacterium with very high genetic variability, we asked whether babA evolves during chronic infection and how mutations or recombination in babA affect binding. We found that BabA-mediated adherence was stable in most individuals but observed a complete loss of binding or reduced binding in 22% of individuals. One strain pair in which binding was lost was used to generate babA sequences that were mosaics of a functional allele and a nonfunctional allele, and the mosaic sequences were used to identify amino acids critically involved in binding of BabA to Lewis b.

Occurrence of Helicobacter pylori and Epstein-Barr virus infection in endoscopic and gastric cancer patients from Northern Brazil

BACKGROUND

Helicobacter pylori (HP) and Epstein-Barr virus (EBV) have been associated with cancer development. We evaluated the prevalence of HP, HP CagA+ and EBV infection in gastric cancer (GC) samples from adults and in gastric tissues from patients who underwent upper endoscopy (UE).

METHODS

Samples from UE and GC were collected to investigate the presence of HP infection and the HP virulence factor CagA by a urease test and PCR. The presence of EBV was detected by Eber-1 in situ hybridization.

RESULTS

In UE, 85.5% of juvenile patients showed some degree of gastritis (45.3% of patients with mild gastritis and 54.7% with moderate/severe gastritis) and patients with mild gastritis were younger than patients with moderate/severe gastritis. Among adults, 48.7% presented mild gastritis and 51.3% moderate/severe gastritis. HP infection was detected in 0% of normal mucosa, 58.5% of juvenile gastritis patients, 69.2% of adult gastritis patients and 88% of GC patients. In these same groups, HP CagA+ was detected in 0%, 37.7%, 61.5% and 67.2% of tissue samples, respectively. In juvenile patients, HP infection was more common in those with gastritis than in normal samples (p = 0.004). The patients with either HP or HP CagA+ were older than patients without these pathogens (p < 0.05). In juvenile patients, HP infection was more frequent in cases of moderate/severe gastritis than in cases of mild gastritis (p = 0.026). Moreover, in patients with GC, HP infection was more frequent in males than in females (p = 0.023). GC patients with HP CagA+ were older than patients with HP CagA- (p = 0.027). HP CagA+ was more common in intestinal-type than diffuse-type GC (p = 0.012). HP CagA+ was also associated with lymph-node (p = 0.024) and distal (p = 0.005) metastasis. No association between EBV infection and HP infection or any clinicopathological variable was detected.

CONCLUSIONS

Our results suggest that HP is involved in the pathophysiology of severe gastric lesions and in the development of GC, particularly when CagA+ is present. EBV was not the primary pathogenic factor in our samples.

Tick-borne encephalitis virus replication, intracellular trafficking, and pathogenicity in human intestinal Caco-2 cell monolayers

Tick-borne encephalitis virus (TBEV) is one of the most important vector-borne viruses in Europe and Asia. Its transmission mainly occurs by the bite of an infected tick. However, consuming milk products from infected livestock animals caused TBEV cases. To better understand TBEV transmission via the alimentary route, we studied viral infection of human intestinal epithelial cells. Caco-2 cells were used to investigate pathological effects of TBEV infection. TBEV-infected Caco-2 monolayers showed morphological changes including cytoskeleton rearrangements and cytoplasmic vacuolization. Ultrastructural analysis revealed dilatation of the rough endoplasmic reticulum and further enlargement to TBEV containing caverns. Caco-2 monolayers maintained an intact epithelial barrier with stable transepithelial electrical resistance (TER) during early stage of infection. Concomitantly, viruses were detected in the basolateral medium, implying a transcytosis pathway. When Caco-2 cells were pre-treated with inhibitors of cellular pathways of endocytosis TBEV cell entry was efficiently blocked, suggesting that actin filaments (Cytochalasin) and microtubules (Nocodazole) are important for PI3K-dependent (LY294002) virus endocytosis. Moreover, experimental fluid uptake assay showed increased intracellular accumulation of FITC-dextran containing vesicles. Immunofluorescence microscopy revealed co-localization of TBEV with early endosome antigen-1 (EEA1) as well as with sorting nexin-5 (SNX5), pointing to macropinocytosis as trafficking mechanism. In the late phase of infection, further evidence was found for translocation of virus via the paracellular pathway. Five days after infection TER was slightly decreased. Epithelial barrier integrity was impaired due to increased epithelial apoptosis, leading to passive viral translocation. These findings illuminate pathomechanisms in TBEV infection of human intestinal epithelial cells and viral transmission via the alimentary route.

Role of energy sensor TlpD of Helicobacter pylori in gerbil colonization and genome analyses after adaptation in the gerbil

Helicobacter pylori maintains colonization in its human host using a limited set of taxis sensors. TlpD is a proposed energy taxis sensor of H. pylori and dominant under environmental conditions of low bacterial energy yield. We studied the impact of H. pylori TlpD on colonization in vivo using a gerbil infection model which closely mimics the gastric physiology of humans. A gerbil-adapted H. pylori strain, HP87 P7, showed energy-dependent behavior, while its isogenic tlpD mutant lost it. A TlpD-complemented strain regained the wild-type phenotype. Infection of gerbils with the complemented strain demonstrated that TlpD is important for persistent infection in the antrum and corpus and suggested a role of TlpD in horizontal navigation and persistent corpus colonization. As a part of the full characterization of the model and to gain insight into the genetic basis of H. pylori adaptation to the gerbil, we determined the complete genome sequences of the gerbil-adapted strain HP87 P7, two HP87 P7 tlpD mutants before and after gerbil passage, and the original human isolate, HP87. The integrity of the genome, including that of a functional cag pathogenicity island, was maintained after gerbil adaptation. Genetic and phenotypic differences between the strains were observed. Major differences between the gerbil-adapted strain and the human isolate emerged, including evidence of recent recombination. Passage of the tlpD mutant through the gerbil selected for gain-of-function variation in a fucosyltransferase gene, futC (HP0093). In conclusion, a gerbil-adapted H. pylori strain with a stable genome has helped to establish that TlpD has important functions for persistent colonization in the stomach.