vacA s1m1 genotype and cagA EPIYA-ABC pattern are predominant among Helicobacter pylori strains isolated from Mexican patients with chronic gastritis

Regulation of Cellular-Signaling Pathways by Mammalian Proteins Containing Bacterial EPIYA or EPIYA-Like Motifs Predicted to be Phosphorylated

The effector proteins of several pathogenic bacteria contain the Glu-Pro-Ile-Tyr-Ala (EPIYA) motif or other similar motifs. The EPIYA motif is delivered into the host cells by type III and IV secretion systems, through which its tyrosine residue undergoes phosphorylation by host kinases. These motifs atypically interact with a wide range of Src homology 2 (SH2) domain-containing mammalian proteins through tyrosine phosphorylation, which leads to the perturbation of multiple signaling cascades, the spread of infection, and improved bacterial colonization. Interestingly, it has been reported that EPIYA (or EPIYA-like) motifs exist in mammalian proteomes and regulate mammalian cellular-signaling pathways, leading to homeostasis and disease pathophysiology. It is possible that pathogenic bacteria have exploited EPIYA (or EPIYA-like) motifs from mammalian proteins and that the mammalian EPIYA (or EPIYA-like) motifs have evolved to have highly specific interactions with SH2 domain-containing proteins. In this review, we focus on the regulation of mammalian cellular-signaling pathways by mammalian proteins containing these motifs.

Helicobacter pylori infection: a dynamic process from diagnosis to treatment

Helicobacter pylori, a gram-negative microaerophilic pathogen, causes several upper gastrointestinal diseases, such as chronic gastritis, peptic ulcer disease, and gastric cancer. For the diseases listed above, H. pylori has different pathogenic mechanisms, including colonization and virulence factor expression. It is essential to make accurate diagnoses and provide patients with effective treatment to achieve positive clinical outcomes. Detection of H. pylori can be accomplished invasively and noninvasively, with both having advantages and limitations. To enhance therapeutic outcomes, novel therapeutic regimens, as well as adjunctive therapies with probiotics and traditional Chinese medicine, have been attempted along with traditional empiric treatments, such as triple and bismuth quadruple therapies. An H. pylori infection, however, is difficult to eradicate during treatment owing to bacterial resistance, and there is no commonly available preventive vaccine. The purpose of this review is to provide an overview of our understanding of H. pylori infections and to highlight current treatment and diagnostic options.

The Helicobacter pylori single nucleotide polymorphisms SNPs associated with multiple therapy resistance in Colombia

The eradication of Helicobacter pylori (H. pylori) using multiple therapies is used as a prevention strategy. However, its efficacy has been compromised by the emergence of single nucleotide polymorphisms in genes associated with H. pylori's resistance to multiple antibiotics. To estimate antibiotic resistance rates associated with mutations in H. pylori genes in the high-cancer-risk population in Colombia, we included 166 H. pylori whole genome sequences from a cohort of individuals with a high risk of gastric cancer. By using the reference strain ATCC 26695, we identified mutations in specific genes to evaluate resistance rates for different antibiotics: 23S rRNA for clarithromycin, 16S rRNA for tetracycline, pbp1A for amoxicillin, gyrA for levofloxacin, and rdxA for metronidazole. The phylogenomic analysis was conducted using the core genome consisting of 1,594 genes of H. pylori-ATCC 26695. Our findings revealed that the resistance rate of H. pylori to clarithromycin was 3.62%, primarily associated with mutations A2143G and A2142G in the 23S rRNA gene. For tetracycline, the resistance rate was 7.23%, with mutations A926G, A926T, and A928C observed in the 16S rRNA gene. Amoxicillin resistance was found in 25.9% of cases, with observed mutations in the pbp1A gene, including T556S, T593, R649K, R656P, and R656H. In the gyrA gene, mutations N87K, N87I, D91G, D91N, and D91Y were identified, resulting in a resistance rate of 12.04% to levofloxacin. The most common mutations in the rdxA gene associated with metronidazole resistance were a stop codon, and mutations at D59N and D59S, resulting in a resistance rate of 99.3%. The high resistance rate of H. pylori to metronidazole indicated that this drug should be excluded from the eradication therapy. However, the resistance rates for tetracycline and clarithromycin did not exceed the established resistance threshold in Colombia. The increased resistance rate of H. pylori to levofloxacin and amoxicillin may partially explain the observed therapeutic failures in Colombia. The phylogenomic tree showed that the H. pylori isolate belongs to its own lineage (hspColombia). These findings offer valuable insights to enhance the characterization of treatment protocols for the specific H. pylori lineage (hspColombia) at the local level.

A Genetic and Immunohistochemical Analysis of Helicobacter pylori Phenotypes and p27 Expression in Adenocarcinoma Patients in Jordan

Stomach (gastric) cancer is one of the most prevalent and deadly cancers worldwide and most gastric cancers are adenocarcinomas. Based on prior research, there is an association between Helicobacter pylori (H. pylori) infection together with the frequency of duodenal ulcer, distal gastric adenocarcinoma, mucosa-associated lymphoid tissue (MALT) lymphoma, and antral gastritis. Helicobacter pylori virulence and toxicity factors have been identified before that significantly influence the clinical outcomes of H. pylori infection and gastric adenocarcinoma. However, it remains unclear exactly how different strains of H. pylori affect gastric adenocarcinoma. Current research suggests this involves tumor suppressor genes, like p27 but also H. pylori toxic virulence proteins. Therefore, we quantified known H. pylori genotypes within adenocarcinoma patients to establish the prevalence of known toxins that include cytotoxin-associated gene A (cagA) as well as vacuolating cytotoxin A (vacA) within patients of variable adenocarcinoma diagnosis. This analysis used gastrectomy samples validated for DNA viability. The incidence of H. pylori in adenocarcinoma patients in Jordan was established to be 54.5% positive (ureA gene positive) with cagA genotype occurrence at 57.1%, but also in this population study vacA gene ratios found to be 24.7%:22.1%:14.3%:14.3%. (vacAs1:vacAs2:vacAm1:vacAm2). Using immunohistochemistry (IHC), we confirmed with statistical significance that p27 was dysregulated and suppressed, within nearly all H. pylori vacA genotypes. In addition, within 24.6% of H. pylori samples analyzed was a different bacterial genotype, and curiously that p27 protein expression was retained in 12% of tested adenocarcinoma H. pylori samples. This is suggestive that p27 could be used as a prognostic indicator but also that an unknown genotype could be contributing to the regulatory effects of p27 protein within this bacterial and cellular environment that may include other virulence factors and unknown immune system regulatory changes.

Effect of Probiotic-Assisted Eradication of cagA+/vacA s1m1 Helicobacter pylori on Intestinal Flora

Objective. We attempted to evaluate the effects of probiotic-assisted eradication of cytotoxin-associated gene A (cagA)+/vacuolating cytotoxin A (vacA) s1m1 Helicobacter pylori (H. pylori) on the intestinal flora, inflammatory factors, and clinical outcomes. Methods. A total of 180 patients with cagA+/vacA s1m1 H. pylori were randomly divided into two groups. Group A was treated with bismuth quadruple therapy (BQT). Group B was treated with S. boulardii in addition to BQT. The distribution of intestinal flora, serum interleukin-8 (IL-8), IL-17, tumor necrosis factor-α (TNF-α) levels, recovery time of clinical symptoms, total effective rate of clinical symptoms, H. pylori eradication rate, and adverse reactions were observed. Results. 2 weeks after treatment, the contents of Bifidobacterium, Bacteroides, and Lactobacillus in the intestinal tract of Group A decreased, while the amounts of Enterococcus and Enterobacter increased. In Group B, the contents of Bifidobacterium, Bacteroides, and Lactobacillus increased, while the amounts of Enterococcus and Enterobacter did not change significantly. Moreover, the trend of this flora change was still present at 4 weeks after treatment. Compared with Group A, Group B had lower IL-8, IL-17, and TNF-α levels, shorter recovery time of clinical symptoms, higher overall efficiency of clinical symptoms, and lower occurrence of adverse reactions. The eradication rate did not differ significantly between the two groups. Conclusion. BQT can lead to intestinal flora disorders in cagA+/vacA s1m1 H. pylori patients. S. boulardii can improve the distribution of intestinal flora, downregulate immune-inflammatory mediators, and modify clinical symptoms in patients.

Helicobacter pylori in Native Americans in Northern Arizona

Background: In Arizona Helicobacter pylori prevalence of infection among Navajo adults is about 62% and gastric cancer incidence rate is 3–4 times higher than that of the non-Hispanic White population. Aim: The aim of this study was to estimate the prevalence of specific H. pylori virulence factors (cagA and vacA) among Navajo patients undergoing and their association with gastric disease. Methods: Virulence genes, cagA and vacA, in H. pylori were investigated in gastric biopsies from 96 Navajo patients over age 18 who were undergoing esophagogastroduodenoscopy. Biopsies from the antrum and fundus were used for molecular characterization to determine cagA type and number of EPIYA motifs and presence of alleles in the signal (s) and medium (m) regions of the vacA gene. Results: H. pylori infection was found in 22.9% of the biopsy samples. The cagA gene amplified in 57.6% of samples and showed a predominant “Western cagA” type, with the EPIYA-ABC motif (45.4%), most prevalent. The vacA allele s1bm1 was the most prevalent (54.5%). Conclusions: H. pylori genotypes were predominantly cagA Western-type and ABC EPIYA motifs. The vacA s1bm1 genotype was the most prevalent and seemed to be associated with gastritis. American Indian/Alaska Native populations are at higher risk for gastric cancer. It is important to identify genotypes of H. pylori and virulence factors involved in the high prevalence of H. pylori and associated disease among the Navajo population.

Helicobacter pylori Virulence Factors-Mechanisms of Bacterial Pathogenicity in the Gastric Microenvironment

Gastric cancer constitutes one of the most prevalent malignancies in both sexes; it is currently the fourth major cause of cancer-related deaths worldwide. The pathogenesis of gastric cancer is associated with the interaction between genetic and environmental factors, among which infection by Helicobacter pylori (H. pylori) is of major importance. The invasion, survival, colonization, and stimulation of further inflammation within the gastric mucosa are possible due to several evasive mechanisms induced by the virulence factors that are expressed by the bacterium. The knowledge concerning the mechanisms of H. pylori pathogenicity is crucial to ameliorate eradication strategies preventing the possible induction of carcinogenesis. This review highlights the current state of knowledge and the most recent findings regarding H. pylori virulence factors and their relationship with gastric premalignant lesions and further carcinogenesis.

CagL polymorphisms D58/K59 are predominant in Helicobacter pylori strains isolated from Mexican patients with chronic gastritis

Background

Helicobacter pylori is a Gram-negative bacterium that colonizes the gastric mucosa in humans. One of the main virulence factors of H. pylori is the cag pathogenicity island (cagPAI), which encodes a type 4-secretion system (T4SS) and the cytotoxin CagA. Translocation of CagA through the T4SS triggers host-signaling pathways. One of the T4SS proteins is CagL, which is necessary for CagA translocation. CagL is a 26-kDa protein that contains a hypervariable motif, which spans residues 58 to 62. Several polymorphisms in this region have been associated with different disease outcomes, e.g. in Mexico, N58 is associated with a higher risk of gastric cancer. The aim of this work is to analyze the sequence of the hypervariable motif (residues 58 to 62) of clinical isolates from Mexican patients with chronic gastritis, and to correlate these polymorphisms with the vacA genotype.

Results

Of the 164 biopsies analyzed, only 30.5% (50/164) were positive for H. pylori. Thirty-six of the 50 clinical isolates (72%) were cagA positive, and 40 (80%) had the most virulent vacA genotype (s1/m1). Of the cagA positive strains, 94.4% were vacA s1/m1. All the cagA⁺ strains contained the cagL gene. The most prevalent sequence in the polymorphic region (residues 58–62) was DKMGE (75.8%, 25/33), followed by NKMGQ and NEIGQ (6.1%, 2/33), and DEIGQ, NKMGE, DKIGE, and DKIGK (3%, 1/33). Regarding polymorphisms in positions 58 and 59, the most common were D58/K59 (81.8%, 27/33), followed by N58/K59 (9.1%, 3/33), and D58/E59 (3%, 1/33). Only two isolates (6.1%) contained residues N58/E59, which correspond to those found in H. pylori strain ATCC 26695. 92.6% of the clinical isolates having polymorphism D58/K59 had the genotype vacA s1/m1, considered to be the most virulent, while 7.4% had the genotypes vacA s1/m2 and s2/m2.

Conclusions

In Mexican patients, CagL polymorphisms D58, K59, M60, E62, K122, and I134 are more common in patients with chronic gastritis.

Penicillin‑binding protein 1A mutation‑positive Helicobacter pylori promotes epithelial‑mesenchymal transition in gastric cancer via the suppression of microRNA‑134

Evidence suggests that Helicobacter pylori (H. pylori) is not only the main cause of gastric cancer (GC), but is also closely associated with its metastasis. One of the major virulence factors in H. pylori is the cytotoxin-associated gene A (CagA). With the growing proportion of amoxicillin-resistant H. pylori strains, the present study aimed to explore the effects of CagA- and penicillin-binding protein 1A (PBP1A) mutation-positive H. pylori (H. pylori_CagA+/P+) on GC cells, and its clinical significance. The clinical significance of H. pylori_CagA+/P+ infection was analyzed in patients with GC. In vitro, GC cells were infected with H. pylori_CagA+/P+ to investigate whether it was involved in the epithelial-mesenchymal transition (EMT) of SGC-7901 cells using immunofluorescence and western blot analysis. The results of clinical analysis demonstrated that, although CagA-negative H. pylori infection had no significant association with the characteristics of patients with GC, H. pylori_CagA+/P+ infection was significantly associated with various clinicopathological parameters, including invasion depth, lymphatic metastasis and distant metastasis. In vitro, the results indicated that H. pylori_CagA+/P+ promoted proliferation, invasion and EMT of SGC-7901 cells. MicroRNA (miR)-134 was downregulated in H. pylori_CagA+/P+ infected tissues compared with in those with H. pylori_CagA+/P- infection. miR-134 overexpression significantly reversed H. pylori_CagA+/P+ infection-associated cell proliferation, invasion and EMT. Furthermore, the results revealed that Forkhead box protein M1 (FoxM1) was a direct target of miR-134, and FoxM1 knockdown impeded H. pylori_CagA+/P+-induced EMT. In conclusion, the present study demonstrated that miR-134 may suppress the proliferation, invasion and EMT of SGC-7901 cells by targeting FoxM1, and may serve a protective role in the process of H. pylori_CagA+/P+-induced GC. These findings may lead to an improved understanding of H. pylori_CagA+/P+-associated poor clinical characteristics in patients with GC.

Epidemiology of Helicobacter pylori infection

This review provides the most recent data concerning the epidemiology of Helicobacter pylori infection. Overall, the trend of declining prevalence of H. pylori infection is continuing, with major evidence available from studies in Europe. However, in some parts of the world, for example, in some countries in the Middle East, the prevalence has remained relatively stable. A number of systematic reviews and meta-analyses have been published during the past year indicating the lowest prevalence rates of the infection in Oceania (24.4%), the highest in Africa (79.1%), and the global annual recurrence rate of H. pylori (4.3%). The recurrence rates were found to be directly related to the human development index and prevalence of infection. Several studies have addressed the correlation between H. pylori infection and sociodemographic conditions, source of drinking water and dietary factors. A hypothesis on the role of insects and yeasts in transmitting H. pylori has been suggested and addressed. Helicobacter sp. have been found in flow flies in Brazil. So far there is no evidence available that H. pylori may survive and persist on the outer body of the fly.