Cytoskeletal rearrangements in gastric epithelial cells in response to Helicobacter pylori infection

Nanomechanical Hallmarks of Helicobacter pylori Infection in Pediatric Patients

Background: the molecular mechanism of gastric cancer development related to Helicobacter pylori (H. pylori) infection has not been fully understood, and further studies are still needed. Information regarding nanomechanical aspects of pathophysiological events that occur during H. pylori infection can be crucial in the development of new prevention, treatment, and diagnostic measures against clinical consequences associated with H. pylori infection, including gastric ulcer, duodenal ulcer, and gastric cancer. Methods: in this study, we assessed mechanical properties of children’s healthy and H. pylori positive stomach tissues and the mechanical response of human gastric cells exposed to heat-treated H. pylori cells using atomic force microscopy (AFM NanoWizard 4 BioScience JPK Instruments Bruker). Elastic modulus (i.e., the Young’s modulus) was derived from the Hertz–Sneddon model applied to force-indentation curves. Human tissue samples were evaluated using rapid urease tests to identify H. pylori positive samples, and the presence of H. pylori cells in those samples was confirmed using immunohistopathological staining. Results and conclusion: collected data suggest that nanomechanical properties of infected tissue might be considered as markers indicated H. pylori presence since infected tissues are softer than uninfected ones. At the cellular level, this mechanical response is at least partially mediated by cell cytoskeleton remodeling indicating that gastric cells are able to tune their mechanical properties when subjected to the presence of H. pylori products. Persistent fluctuations of tissue mechanical properties in response to H. pylori infection might, in the long-term, promote induction of cancer development.

Drosophila as a Model for Infectious Diseases

The fruit fly, Drosophila melanogaster, has been used to understand fundamental principles of genetics and biology for over a century. Drosophila is now also considered an essential tool to study mechanisms underlying numerous human genetic diseases. In this review, we will discuss how flies can be used to deepen our knowledge of infectious disease mechanisms in vivo. Flies make effective and applicable models for studying host-pathogen interactions thanks to their highly conserved innate immune systems and cellular processes commonly hijacked by pathogens. Drosophila researchers also possess the most powerful, rapid, and versatile tools for genetic manipulation in multicellular organisms. This allows for robust experiments in which specific pathogenic proteins can be expressed either one at a time or in conjunction with each other to dissect the molecular functions of each virulent factor in a cell-type-specific manner. Well documented phenotypes allow large genetic and pharmacological screens to be performed with relative ease using huge collections of mutant and transgenic strains that are publicly available. These factors combine to make Drosophila a powerful tool for dissecting out host-pathogen interactions as well as a tool to better understand how we can treat infectious diseases that pose risks to public health, including COVID-19, caused by SARS-CoV-2.

Virulence of Helicobacter pylori outer membrane proteins: an updated review

Helicobacter pylori (H. pylori) infection is associated with some gastric diseases, such as gastritis, peptic ulcer, and gastric cancer. CagA and VacA are known virulence factors of H. pylori, which play a vital role in severe clinical outcomes. Additionally, the expression of outer membrane proteins (OMPs) helps H. pylori attach to gastric epithelial cells at the primary stage and increases the virulence of H. pylori. In this review, we have summarized the paralogs of H. pylori OMPs, their genomic loci, and the different receptors of OMPs identified so far. We focused on five OMPs, BabA (HopS), SabA (HopP), OipA (HopH), HopQ, and HopZ, and one family of OMPs: Hom. We highlight the coexpression of OMPs with other virulence factors and their relationship with clinical outcomes. In conclusion, OMPs are closely related to the pathogenic processes of adhesion, colonization, persistent infection, and severe clinical consequences. They are potential targets for the prevention and treatment of H. pylori–related diseases.

Priming the seed: Helicobacter pylori alters epithelial cell invasiveness in early gastric carcinogenesis

Helicobacter pylori (H. pylori) infection is a well-established risk factor for the development of gastric cancer (GC), one of the most common and deadliest neoplasms worldwide. H. pylori infection induces chronic inflammation in the gastric mucosa that, in the absence of treatment, may progress through a series of steps to GC. GC is only one of several clinical outcomes associated with this bacterial infection, which may be at least partially attributed to the high genetic variability of H. pylori. The biological mechanisms underlying how and under what circumstances H. pylori alters normal physiological processes remain enigmatic. A key aspect of carcinogenesis is the acquisition of traits that equip preneoplastic cells with the ability to invade. Accumulating evidence implicates H. pylori in the manipulation of cellular and molecular programs that are crucial for conferring cells with invasive capabilities. We present here an overview of the main findings about the involvement of H. pylori in the acquisition of cell invasive behavior, specifically focusing on the epithelial-to-mesenchymal transition, changes in cell polarity, and deregulation of molecules that control extracellular matrix remodeling.

Attaching-and-Effacing Pathogens Exploit Junction Regulatory Activities of N-WASP and SNX9 to Disrupt the Intestinal Barrier

BACKGROUND & AIMS

Neural Wiskott-Aldrich Syndrome protein (N-WASP) is a key regulator of the actin cytoskeleton in epithelial tissues and is poised to mediate cytoskeletal-dependent aspects of apical junction complex (AJC) homeostasis. Attaching-and-effacing (AE) pathogens disrupt this homeostasis through translocation of the effector molecule early secreted antigenic target-6 (ESX)-1 secretion-associated protein F (EspF). Although the mechanisms underlying AJC disruption by EspF are unknown, EspF contains putative binding sites for N-WASP and the endocytic regulator sorting nexin 9 (SNX9). We hypothesized that N-WASP regulates AJC integrity and AE pathogens use EspF to induce junction disassembly through an N-WASP- and SNX9-dependent pathway.

METHODS

We analyzed mice with intestine-specific N-WASP deletion and generated cell lines with N-WASP and SNX9 depletion for dynamic functional assays. We generated EPEC and Citrobacter rodentium strains complemented with EspF bearing point mutations abolishing N-WASP and SNX9 binding to investigate the requirement for these interactions.

RESULTS

Mice lacking N-WASP in the intestinal epithelium showed spontaneously increased permeability, abnormal AJC morphology, and mislocalization of occludin. N-WASP depletion in epithelial cell lines led to impaired assembly and disassembly of tight junctions in response to changes in extracellular calcium. Cells lacking N-WASP or SNX9 supported actin pedestals and type III secretion, but were resistant to EPEC-induced AJC disassembly and loss of transepithelial resistance. We found that during in vivo infection with AE pathogens, EspF must bind both N-WASP and SNX9 to disrupt AJCs and induce intestinal barrier dysfunction.

CONCLUSIONS

Overall, these studies show that N-WASP critically regulates AJC homeostasis, and the AE pathogen effector EspF specifically exploits both N-WASP and SNX9 to disrupt intestinal barrier integrity during infection.

Nutrition and Helicobacter pylori: Host Diet and Nutritional Immunity Influence Bacterial Virulence and Disease Outcome

Helicobacter pylori colonizes the stomachs of greater than 50% of the world's human population making it arguably one of the most successful bacterial pathogens. Chronic H. pylori colonization results in gastritis in nearly all patients; however in a subset of people, persistent infection with H. pylori is associated with an increased risk for more severe disease outcomes including B-cell lymphoma of mucosal-associated lymphoid tissue (MALT lymphoma) and invasive adenocarcinoma. Research aimed at elucidating determinants that mediate disease progression has revealed genetic differences in both humans and H. pylori which increase the risk for developing gastric cancer. Furthermore, host diet and nutrition status have been shown to influence H. pylori-associated disease outcomes. In this review we will discuss how H. pylori is able to create a replicative niche within the hostile host environment by subverting and modifying the host-generated immune response as well as successfully competing for limited nutrients such as transition metals by deploying an arsenal of metal acquisition proteins and virulence factors. Lastly, we will discuss how micronutrient availability or alterations in the gastric microbiome may exacerbate negative disease outcomes associated with H. pylori colonization.

Regulators of Actin Dynamics in Gastrointestinal Tract Tumors

Reorganization of the actin cytoskeleton underlies cell migration in a wide variety of physiological and pathological processes, such as embryonic development, wound healing, and tumor cell invasion. It has been shown that actin assembly and disassembly are precisely regulated by intracellular signaling cascades that respond to changes in the cell microenvironment, ligand binding to surface receptors, or oncogenic transformation of the cell. Actin-nucleating and actin-depolymerizing (ANFs/ADFs) and nucleation-promoting factors (NPFs) regulate cytoskeletal dynamics at the leading edge of migrating cells, thereby modulating cell shape; these proteins facilitate cellular movement and mediate degradation of the surrounding extracellular matrix by secretion of lytic proteases, thus eliminating barriers for tumor cell invasion. Accordingly, expression and activity of these actin-binding proteins have been linked to enhanced metastasis and poor prognosis in a variety of malignancies. In this review, we will summarize what is known about expression patterns and the functional role of actin regulators in gastrointestinal tumors and evaluate first pharmacological approaches to prevent invasion and metastatic dissemination of malignant cells.

Morphology and infectivity of virus that persistently caused infection in an AGS cell line

A recent report has indicated that proteins and genes of simian virus 5 (SV5) are detected in a human gastric adenocarcinoma (AGS) cell line, which is widely provided for oncology, immunology, and microbiology research. However, the production of infective virions has not been determined in this cell line. In this study, the morphology and infectivity of the virus particles of the AGS cell line were studied by light and electron microscopy and virus transmission assay. The virus particles were approximately 176.0 ± 41.1 nm in diameter. The particles possessed projections 8-12 nm long on the surface and contained a nucleocapsid determined to be 13-18 nm in width and less than 1,000 nm in length. The virus was transmissible to the Vero cell line, induced multinuclear giant cell formation, and reproduced the same shape of antigenic virions. In this study, the persistently infected virus in the AGS cell line was determined to be infective and form reproducible virions, and a new morphological feature of SV5 was determined.

Paxillin is a novel cellular target for converging Helicobacter pylori-induced cellular signaling

Paxillin is involved in the regulation of Helicobacter pylori-mediated gastric epithelial cell motility. We investigated the signaling pathways regulating H. pylori-induced paxillin phosphorylation and the effect of the H. pylori virulence factors cag pathogenicity island (PAI) and outer inflammatory protein (OipA) on actin stress fiber formation, cell phenotype, and IL-8 production. Gastric cell infection with live H. pylori induced site-specific phosphorylation of paxillin tyrosine (Y) 31 and Y118 in a time- and concentration-dependent manner. Activated paxillin localized in the cytoplasm at the tips of H. pylori-induced actin stress fibers. Isogenic oipA mutants significantly reduced paxillin phosphorylation at Y31 and Y118 and reduced actin stress fiber formation. In contrast, cag PAI mutants only inhibited paxillin Y118 phosphorylation. Silencing of epidermal growth factor receptor (EGFR), focal adhesion kinase (FAK), or protein kinase B (Akt) expression by small-interfering RNAs or inhibiting kinase activity of EGFR, Src, or phosphatidylinositol 3-kinase (PI3K) markedly reduced H. pylori-induced paxillin phosphorylation and morphologic alterations. Reduced FAK expression or lack of Src kinase activity suppressed H. pylori-induced IL-8 production. Compared with infection with the wild type, infection with the cag PAI mutant and oipA mutant reduced IL-8 production by nearly 80 and 50%. OipA-induced IL-8 production was FAK- and Src-dependent, although a FAK/Src-independent pathway for IL-8 production also exists, and the cag PAI may be mainly involved in this pathway. We propose paxillin as a novel cellular target for converging H. pylori-induced EGFR, FAK/Src, and PI3K/Akt signaling to regulate cytoskeletal reorganization and IL-8 production in part, thus contributing to the H. pylori-induced diseases.

Benefits of Helicobacter pylori cagE genotyping in addition to cagA genotyping: a Bulgarian study

Associations of Helicobacter pylori cagE status with complex patient characteristics remain to be elucidated in Eastern Europe. The aim of this study was to assess the frequencies of cagE gene and cagA/cagE combinations in H. pylori strains from symptomatic Bulgarian patients and to improve cagA detection. cagA and cagE genotypes were evaluated in 219 patients with single-strain infections. In total, 84.9% of strains were cagA (+), while 68.5% were cagE (+). cagA (+), cagE (+), and cagA (+)/cagE (+) strains were more prevalent in peptic ulcer (93.8%, 84.4%, and 84.4%) compared with nonulcer patients (81.3%, 61.9%, and 61.3%, respectively). In elderly patients, cagE (+) and cagA (+)/cagE (+) strains were 1.9-fold more common than in the 12 children evaluated. Only 10% of the elderly subjects harbored low-virulence cagA (+)/cagE (-) strains compared with 16.8% of adults and 41.7% of children. Intriguingly, prevalence of the cagA (+)/cagE (-) genotype was 2.1-fold lower in men than in women, suggesting a higher frequency of more virulent strains in men. The presence of both cag genes and combinations was not linked to strain susceptibility to clarithromycin or metronidazole, place of residence, or prior therapy. Use of an extra primer pair increased cagA detection in 14.7% of 31 cagA (-) strains. In conclusion, use of a second primer pair for the cagA gene can be recommended in countries with common cagA (+) strains. Although both cag genes were linked to severe diseases in Bulgarian patients, the best discrimination of virulent strains was obtained by the cagA/cagE combination or by the cagE gene alone. cagE prevalence increased gradually with patient age, while the cagA (+)/cagE (-) genotype, implying a disrupted cag pathogenicity island, was associated with both younger age and female gender.

Cytoskeletal regulation of epithelial barrier function during inflammation

Increased epithelial permeability is a common and important consequence of mucosal inflammation that results in perturbed body homeostasis and enhanced exposure to external pathogens. The integrity and barrier properties of epithelial layers are regulated by specialized adhesive plasma membrane structures known as intercellular junctions. It is generally believed that inflammatory stimuli increase transepithelial permeability by inducing junctional disassembly. This review highlights molecular events that lead to disruption of epithelial junctions during inflammation. We specifically focus on key mechanisms of junctional regulation that are dependent on reorganization of the perijunctional F-actin cytoskeleton. We discuss critical roles of myosin-II-dependent contractility and actin filament turnover in remodeling of the F-actin cytoskeleton that drive disruption of epithelial barriers under different inflammatory conditions. Finally, we highlight signaling pathways induced by inflammatory mediators that regulate reorganization of actin filaments and junctional disassembly in mucosal epithelia.

Lactobacillus salivarius modulates cytokine induction and virulence factor gene expression in Helicobacter pylori

Human infection by the gastric pathogen Helicobacter pylori is characterized by a robust immune response which rarely prevents persistent H. pylori colonization. Emerging evidence suggests that lactobacilli may reduce H. pylori infection rates and associated inflammation. In this study, we measured the ability of two model strains of Lactobacillus salivarius (UCC118 and UCC119) to modulate gastric epithelial cell chemokine responses to H. pylori infection. Pre-treatment of AGS cells with either L. salivarius strain significantly decreased interleukin-8 (IL-8) production upon exposure to H. pylori, but not in cells stimulated with TNF-alpha. The production of the chemokines CCL20 and IP-10 by AGS cells infected with H. pylori was also altered following pre-treatment with UCC118 and UCC119. We showed that a greater reduction in IL-8 production with UCC119 was due to the production of more acid by this strain. Furthermore, UV-killed cells of both lactobacillus strains were still able to reduce H. pylori-induced IL-8 in the absence of acid production, indicating the action of a second anti-inflammatory mechanism. This immunomodulatory activity was not dependent on adhesion to epithelial cells or bacteriocin production. Real-time RT-PCR analysis showed that expression of eight of twelve Cag pathogenicity island genes tested was downregulated by exposure to L. salivarius, but not by cells of four other lactobacillus species. CagA accumulated in H. pylori cells following exposure to L. salivarius presumably as a result of loss of functionality of the Cag secretion system. These data identified a new mechanism whereby some probiotic bacteria have a positive effect on H. pylori-associated inflammation without clearing the infection.

Differential regulation of ERK1/2 and p38 MAP kinases in VacA-induced apoptosis of gastric epithelial cells

Helicobacter pylori vacuolating cytotoxin A (VacA) has been considered as an apoptosis-inducing factor. Here, we investigated the mechanism of VacA-induced apoptosis in relation to the defense mechanism and MAP kinases pathway in gastric epithelial cells. AGS cells exposed to enriched VacA extracts affected the level of SOD-1 and villin. We further investigated the role of VacA in those inductions using a functional recombinant VacA (rVacA). Activation of p38 MAPK and Bax dimerization by rVacA were increased in a dose-dependent manner. rVacA-induced ERK1/2 MAPK activation was maximal at 30 min and 4 h and 1-4 microg/ml of rVacA. rVacA-induced SOD-1 expression was considerably diminished by inhibiting ERK1/2 MAPK and it was slightly increased by inhibiting p38 MAPK. rVacA increased or decreased villin expression depending on dose and exposure time and its expression was mainly appeared in the contractile actin ring of the dividing cells. Despite its cytoprotective effect, SB-203580, a p38 inhibitor, was unlikely to reduce VacA-induced Bax dimerization and rather inhibited villin and Bcl2 expression, indicating that p38 may also play a role in cell proliferation or differentiation for survival after VacA intoxication. Furthermore, p38 inhibitor accelerated rVacA-induced cell death after exposure of AGS cells to H(2)O(2) but ERK1/2 inhibitor protected cells from H(2)O(2) insult. These results suggest that SOD-1 and villin are expressed differentially upon VacA insult depending on dose and exposure time via ERK and p38 MAP kinases; decrease in SOD-1 and villin expression coupled with Bax dimerization leads to apoptosis of gastric epithelial cells.

OipA plays a role in Helicobacter pylori-induced focal adhesion kinase activation and cytoskeletal re-organization

The initial signalling events leading to Helicobacter pylori infection associated changes in motility, cytoskeletal reorganization and elongation of gastric epithelial cells remain poorly understood. Because focal adhesion kinase (FAK) is known to play important roles in regulating actin cytoskeletal organization and cell motility we examined the effect of H. pylori in gastric epithelial cells co-cultured with H. pylori or its isogenic cag pathogenicity island (PAI) or oipA mutants. H. pylori induced FAK phosphorylation at distinct tyrosine residues in a dose- and time-dependent manner. Autophosphorylation of FAK Y397 was followed by phosphorylation of Src Y418 and resulted in phosphorylation of the five remaining FAK tyrosine sites. Phosphorylated FAK and Src activated Erk and induced actin stress fibre formation. FAK knock-down by FAK-siRNA inhibited H. pylori-mediated Erk phosphorylation and abolished stress fibre formation. Infection with oipA mutants reduced phosphorylation of Y397, Y576, Y577, Y861 and Y925, inhibited stress fibre formation and altered cell morphology. cag PAI mutants reduced phosphorylation of only FAK Y407 and had less effect on stress fibre formation than oipA mutants. We propose that activation of FAK and Src are responsible for H. pylori-induced induction of signalling pathways resulting in the changes in cell phenotype important for pathogenesis.

Effects of transfection reagents and Helicobacter pylori on morphology of AGS cells

AIM: To investigate the effects of different transfection reagents on the morphology of AGS cells and to explore whether these reagents can induce humming bird type of AGS cells as Helicobacter pylori (H. pylori) does.

METHODS: AGS cells were transfected with polycation transfection reagents (polyethylenimine, Sofast Cell Transfection reagent) and the new generation of lipid transfection reagents (Effectene Transfection Reagent). Then morphological changes of the cells were observed. Meanwhile, AGS cells were infected with H. pylori 26695, and then the morphology of the cells was compared with that of the cells transfected with transfection reagents.

RESULTS: H. pylori 26695 induced humming bird type of AGS cells 4 h after infection. Both polycation transfection reagents also induced humming bird type of AGS cells, and the cells were elongated in shape, which was similar to that induced by H. pylori 26695. The humming bird type always appeared whether the cells were transfected with DNA or without DNA at 4 h. The morphological changes were positively related with the dosages of the reagents. The apoptosis of the cells were observed when 10 µL reagents were used, and it became severe as the dosage reached 15 µL. The new generation of lipid transfection reagents had no effect on the morphology of AGS cells.

CONCLUSION: Polycation transfection reagents should not be used in the research of AGS cell morphology. Further study should be performed to find out whether there are some common pathways between the morphology variation induced by H　pylori and polycation transfection reagents.

Impact of Helicobacter pylori virulence factors and compounds on activation and maturation of human dendritic cells

Recently, we and others have shown that Helicobacter pylori induces dendritic cell (DC) activation and maturation. However, the impact of virulence factors on the interplay between DCs and H. pylori remains elusive. Therefore, we investigated the contribution of cag pathogenicity island (PAI) and VacA status on cytokine release and up-regulation of costimulatory molecules in H. pylori-treated DCs. In addition, to characterize the stimulatory capacity of H. pylori compounds in more detail, we studied the effect of formalin-inactivated and sonicated H. pylori, as well as secreted H. pylori molecules, on DCs. Incubation of DCs with viable or formalin-inactivated H. pylori induced comparable secretion of interleukin-6 (IL-6), IL-8, IL-10, IL-12, IL-1beta, and tumor necrosis factor (TNF). In contrast, IL-12 and IL-1beta release was significantly reduced in DCs treated with sonicated bacteria and secreted bacterial molecules. Treatment of sonicated H. pylori preparations with polymyxin B resulted in a significant reduction of IL-8 and IL-6 secretion, suggesting that H. pylori-derived lipopolysaccharide at least partially contributes to activation of immature DCs. In addition, the capacity of H. pylori-pulsed DCs to activate allogeneic T cells was not affected by cag PAI and VacA. Pretreatment of DC with cytochalasin D significantly inhibited secretion of IL-12, IL-1beta, and TNF, indicating that phagocytosis of H. pylori contributes to maximal activation of DCs. Taken together, our results suggest that DC activation and maturation, as well as DC-mediated T-cell activation, are independent of the cag PAI and VacA status of H. pylori.

Helicobacter pyloriVacA cytotoxin interacts with fibronectin and alters HeLa cell adhesion and cytoskeletal organization in vitro

Helicobacter pylori vacuolating cytotoxin VacA causes multiple effects on epithelial cell function and morphology, but the effects of VacA on signal transduction pathways and the cytoskeleton have not been investigated in detail. In this study, we analyzed the effects of native VacA on HeLa and AGS cell adhesion to fibronectin and laminin under serum-free conditions. Confocal microscopic examination revealed increased number of cells with rounded morphology and inhibition of actin fiber formation, in the presence of VacA. VacA binds to fibronectin in vitro in a dose-dependent manner. This interaction was partly inhibited by a peptide containing an arginine-glycine-aspartic acid motif. The adhesion of HeLa cells to fibronectin, but not to laminin, was decreased in the presence of VacA. Thus, VacA may interact with fibronectin and influence integrin receptor-induced cell signaling and cytoskeleton-dependent cell functions.

Protective role of heat shock protein 27 in gastric mucosal injury

Heat shock protein 27 (HSP27) mediates cytoprotective effects through its function as a molecular chaperone and through the phosphorylation-dependent stabilization of actin filaments. The role of HSP27 in gastric ulcer formation and healing is, however, unknown. The expression of HSP27 was studied in human gastric tissue specimens obtained from patients with gastric ulcers and from healthy Helicobacter pylori-negative individuals, who received low-dose aspirin, rofecoxib, and the combination in a prospective study. The susceptibility of the gastric mucosa to indomethacin-induced lesions was further studied in transgenic mice overexpressing human HSP27 (Tg(huHSP27)) and compared with wild-type mice (Wt). The expression of HSP27, COX-1, and COX-2 was investigated in Tg(huHSP27) mice and Wt mice by immunohistochemistry and western blot analysis. While no specific changes in HSP27 expression were found following exposure of healthy human gastric mucosa to oral administration of aspirin or refocoxib, chronic gastric ulcers showed strong HSP27 expression at the ulcer base and margins. Here it was expressed by granulation tissue and regenerating surface epithelium. In Tg(huHSP27) mice, overexpression of HSP27 led to a significant decrease of indomethacin-induced erosions and ulcers compared with Wt mice. COX-1 and COX-2 levels did not change. HSP27 is involved in chronic gastric ulcer repair mechanisms in humans, while overexpression of human HSP27 in gastric epithelial cells in mice reduces the susceptibility to non-steroidal anti-inflammatory drug (NSAID)-induced gastric ulceration. This indicates that HSP27 expression is critical for mucosal protection in the stomach.

Helicobacter pylori infection: anything new should we know?

Over the past year, 2003-4, there have been a number of studies consolidating previous work in relation to pathogenesis of disease, diagnosis and management of Helicobacter pylori. Studies into the pathogenesis of disease have identified the main adhesin of H. pylori as an important virulence marker and as a potential target for therapy. Molecular investigations of both the strain and host variations have identified the action of several of the virulence factors, e.g. cagA, vacA, on disrupting host cell signalling and the consequences in respect of the release of chemokines from the damaged gastric epithelium and the effect on apoptosis. Over the past year, there have been further diagnostic kits developed based on modifications of current technology. Two promising areas of research for diagnosis are the use of host/strain genome polymorphisms as a means of identifying high-risk patients who may develop severe disease and the use of proteomics to identify potential antigens of diagnostic (or therapeutic) use. The three main antibiotics that are used in first-line eradication regimens are clarithromycin, metronidazole and amoxycillin. Of these, metronidazole has the highest prevalence of resistance, followed by clarithromycin; amoxycillin resistance is only rarely reported. The decreasing success of current first-line therapy is the driving force for the development of new antibiotic combinations and a search for novel sources for chemotherapeutic agents and novel therapeutic targets.