The Human Gastric Pathogen<i>Helicobacter pylori</i>and Its Association with Gastric Cancer and Ulcer Disease

Bauer, Bianca; Meyer, Thomas F.

doi:10.1155/2011/340157

Cited by 94 publications

(69 citation statements)

References 243 publications

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“…One alternative to human demography may be stronger selection in Africa, a notion that is consistent with the larger number of putatively adaptive regions identified in Africa, relative to other sampled populations ( Figure 3 and Table S3). Despite the very high prevalence of H. pylori on this continent, a significant association with the incidence of gastric diseases has never been demonstrated (Graham et al 2007;Bauer and Meyer 2011). The opposite is true in non-African strains, where we show that H. pylori had a very low ancestral effective population size, coupled with the high population growth rates in our global sample.…”

Section: Discussioncontrasting

confidence: 63%

“…Genes falling into the functional categories explained in the discussion are color coded as reported in the legend, while remaining are in black. This figure was generated using R bioconductor package genoPlotR (Guy et al 2010). 2010; Bauer and Meyer 2011;Matsunari et al 2012;Shiota et al 2013). TheAfrica2 population shows the strongest evidence of recurrent local adaptation, a result that is perhaps intuitive given its long association with the San, one of the most ancient of human groups.…”

Section: Worldwide and Population-specific Genes Under Selectionmentioning

confidence: 99%

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Worldwide Population Structure, Long-Term Demography, and Local Adaptation of Helicobacter pylori

et al. 2015

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Helicobacter pylori is an important human pathogen associated with serious gastric diseases. Owing to its medical importance and close relationship with its human host, understanding genomic patterns of global and local adaptation in H. pylori may be of particular significance for both clinical and evolutionary studies. Here we present the first such whole genome analysis of 60 globally distributed strains, from which we inferred worldwide population structure and demographic history and shed light on interesting global and local events of positive selection, with particular emphasis on the evolution of San-associated lineages. Our results indicate a more ancient origin for the association of humans and H. pylori than previously thought. We identify several important perspectives for future clinical research on candidate selected regions that include both previously characterized genes (e.g., transcription elongation factor NusA and tumor necrosis factor alpha-inducing protein Tipa) and hitherto unknown functional genes.KEYWORDS adaptation; neutral evolution; human pathogens H ELICOBACTER pylori is a Gram-negative bacterium that infects the mucosa of the human stomach. It was first described in the 1980s, when it was initially identified in association with chronic gastritis and later causally linked to serious gastric pathologies such as gastric cancer and ulcers (Marshall and Warren 1984;Suerbaum and Michetti 2002). It infects .80% of humans in developing countries and, although its prevalence is lower in developed countries, nearly 50% of the worldwide human population is infected (Ghose et al. 2005;Salih 2009;Salama et al. 2013).Due to its clinical and evolutionary importance, there has been considerable research on mechanisms of H. pylori transmission, as well as on the population genetics and phylogenetic relationships among global isolates. Thus far, population genetic analyses have mainly focused on seven housekeeping genes (usually referred to as multilocus sequence typing or MLST), with the primary conclusions being that H. pylori strains appear highly structured, and their phylogeographic patterns correlate consistently with that of their human hosts. Given that the H. pylori-humans association is at least 100,000 years old (Moodley et al. 2012), the current population structure of H. pylori may be regarded as mirroring past human expansions and migrations Linz et al. 2007;Breurec et al. 2011) and thus help us shed light on yet unknown dynamics of local demographic processes in human evolution. However, despite the knowledge gained thus far, the long-term global demographic history of H. pylori has never been directly inferred. The long, intimate association of H. pylori with humans suggests a history of bacterial adaptation. Considerable attention has focused on specific genes involved in modulating adaptive immunity of the host (for a review see Yamaoka 2010 andSalama et al. 2013) and on genomic changes occurring during acute and chronic H. pylori infection (Kennemann et al. 2011;Linz et a...

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Section: Discussioncontrasting

confidence: 63%

Section: Worldwide and Population-specific Genes Under Selectionmentioning

confidence: 99%

Worldwide Population Structure, Long-Term Demography, and Local Adaptation of Helicobacter pylori

et al. 2015

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“…In the majority of cases, H. pylori infection induces chronic gastritis with a rate of 80% to 90% and to 10% of infected individuals can develop peptic ulcers and 1-3% presents a risk of developing gastric cancer [7,[30][31][32]. Our study showed that the most common pathology resulting from H. pylori infection was chronic gastritis with a rate of 66%, followed by atrophic gastritis (12%), intestinal metaplasia (8%), and gastric cancer (9%).…”

Section: Discussionmentioning

confidence: 99%

Epidemiology of Helicobacter pylori Infection and Related Gastric Pathologies in Moroccan Population

Bounder¹,

Boura²,

SalouaNadifiyine³

et al. 2017

JLS

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Abstract:Helicobacter pylori (H. pylori) colonize the gastric mucosa of 50% of the world's population. This infection is closely associated with the development of peptic ulcer disease and gastric cancer. The present study was conducted to assess the prevalence of H. pylori infection in Moroccan population and the risk to develop gastric precancerous lesions and gastric cancer. Totally, 298 patients were enrolled, 68 of asymptomatic subjects and 230 of patients with gastric diseases. Histological examination was effected to diagnostic gastric lesions and to detect H. pylori. ELISA was used to determine H. pylori status of patients. The prevalence of H. pylori within asymptomatic and symptomatic subjects was observed higher. A significant relationship was detected between H. pylori infection and the risk of gastric diseases (p-value < 0.0001). A meaningful association between chronic gastritis increasing and age was observed (p-value = 0.03). The risk to develop gastric cancer among infected patients was observed elevated with rate of 9%. Our results showed a high prevalence of H. pylori in both asymptomatic and gastric diseases patients. We noticed that chronic gastric infection increases with age. We remarked also that the risk to develop gastric cancer among infected patients was elevated in our population.

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“…Two of the AMPs tested (LL-37 and magainin I) were relatively weakly active against all of the strains, while cecropin gave much lower MICs. Isolation of drug-resistant forms of Helicobacter pylori have led to concerns about the inability to eradicate chronic infections leading to gastric adenocarcinoma [65].…”

Section: Antibacterial Activitymentioning

confidence: 99%

Ceragenins as Mimics of Endogenous Antimicrobial Peptides

Hashemi¹,

Holden²,

DurnaÅ³

et al. 2017

J Antimicrob Agents

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Ceragenins are small molecule mimics of endogenous antimicrobial peptides (AMPs), and as such display broadspectrum antimicrobial activity. These molecules are derived from a common bile acid and can be prepared at a large scale. Because ceragenins are not peptide based, they are not substrates for proteases. Gram-negative and positive bacteria are susceptible to ceragenins, including drug resistant organisms. Although ceragenins and colistin have common features, ceragenins retain full antibacterial activity against colistin-resistant Gram-negative bacteria. Bactericidal activity of ceragenins involves selective association with bacterial membranes followed by membrane depolarization. Due to this mechanism of action, which provides bactericidal activity against sessile bacteria, ceragenins eradicate established biofilms. Lipid-enveloped viruses (e.g. vaccinia) are deactivated by ceragenins, and topical application of a lead ceragenin decreases transmission of the virus in skin in a murine model. More recently, the activities of ceragenins against fungal pathogens have been reported, with minimum inhibition concentrations comparable to clinically used anti-fungal agents. In addition to antimicrobial activities, ceragenins have been shown to display some of the "secondary" activities attributed to AMPs. In vivo use of ceragenins to eradicate biofilms, prevent infection and accelerate bone growth demonstrate some of the types of applications in which ceragenins may be used to augment or replace activities of endogenous AMPs.

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The Human Gastric PathogenHelicobacter pyloriand Its Association with Gastric Cancer and Ulcer Disease

Cited by 94 publications

References 243 publications

Worldwide Population Structure, Long-Term Demography, and Local Adaptation of Helicobacter pylori

Worldwide Population Structure, Long-Term Demography, and Local Adaptation of Helicobacter pylori

Epidemiology of Helicobacter pylori Infection and Related Gastric Pathologies in Moroccan Population

Ceragenins as Mimics of Endogenous Antimicrobial Peptides

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