• Users Online: 1533
  • Home
  • Print this page
  • Email this page
Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 

 Table of Contents  
Year : 2019  |  Volume : 31  |  Issue : 4  |  Page : 550-555

Gastroduodenal pathology in the light of Helicobacter pylori genotype in Egyptian patients

1 Department of Internal Medicine, Faculty of Medicine, Alexandria University, Alexandria, Egypt
2 Department of Microbiology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
3 Department of General Surgery, High Research Institute, Alexandria University, Alexandria, Egypt

Date of Submission10-Jul-2019
Date of Acceptance06-Sep-2019
Date of Web Publication18-Aug-2020

Correspondence Address:
Eman Azzam
Associate Professor of Internal Medicine, Department of Internal Medicine, Faculty of Medicine, Alexandria University, Alexandria,
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ejim.ejim_99_19

Rights and Permissions

Context Infection with Helicobacter pylori is associated with gastroduodenal diseases such as gastritis, gastric ulcer, duodenal ulcer, gastric cancer, and mucosa-associated lymphoid tissue lymphoma.
Aim The aim of this study was to detect the nature of gastroduodenal pathology in the light of the genotype of the associated H. pylori organism.
Materials and methods The study was conducted on 100 patients with upper gastrointestinal tract symptoms; infection with H. pylori was detected by stool antigen test. Moreover, 20 asymptomatic patients, infected with H. pylori, were included in the study as controls. Upper gastrointestinal tract endoscopy was performed in all participants to take biopsies to diagnose the disease microscopically and to determine H. pylori virulence factors [cytotoxin-associated protein A (CagA) and VacA] by PCR.
Results Patients infected by H. pylori organisms having CagA-positive genes (41 patients) developed gastritis in 53.7%, peptic ulcer disease (PUD) in 36.6%, and gastric malignancy in 9.8%. Patients infected with organisms that have VacA s1 in addition to CagA genes (19 patients) were found to have gastritis in 21.1%, PUD in 63.2%, and gastric malignancy in 15.8%. However, patients infected with H. pylori organism that have VacAs2 in addition to CagA genes (34 patients) developed gastritis in 79.4%, PUD in 20.6%, and no malignancy.
Discussion The presence of VacA s1 gene in addition to CagA significantly increases the virulence of the organism toward development of PUD and gastric malignancy. The presence of VacA s2 gene significantly decreases the virulence of CagA gene to develop PUD and prevent completely its carcinogenicity.

Keywords: CagA, gastric malignancies, gastroduodenal diseases, H. pylori, PUD, VacA

How to cite this article:
Azzam E, Ali E, Ahmed S, Talha A. Gastroduodenal pathology in the light of Helicobacter pylori genotype in Egyptian patients. Egypt J Intern Med 2019;31:550-5

How to cite this URL:
Azzam E, Ali E, Ahmed S, Talha A. Gastroduodenal pathology in the light of Helicobacter pylori genotype in Egyptian patients. Egypt J Intern Med [serial online] 2019 [cited 2020 Sep 27];31:550-5. Available from: http://www.esim.eg.net/text.asp?2019/31/4/550/292266

  Introduction Top

Helicobacter pylori is a Gram-negative spiral-shaped microorganism ∼3 μm long with a diameter of ∼0.5 μm and has 4–6 flagella that make it highly motile [1]. It is currently estimated that approximately half of the world population is infected with the H. pylori [2].

H. pylori colonizes the gastric epithelium of the human stomach early in life (<10 years of age) and remains latent in most infected patients [3],[4]. It becomes symptomatic later in life when the infection results in development of gastroduodenal disease. The frequency and severity of disease outcome differs between infected patients and depends on interplay between the virulence of the infecting strain of the bacterium, the type and severity of the patients’ immune response, and environmental factors [5].

H. pylori strains possess specific virulence factors that play an important role in the development of gastritis, peptic ulcer diseases (PUD), gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma [6]. One of these virulence factors is the cytotoxin-associated protein A (CagA protein) encoded by the cytotoxin-associated gene (CagA gene) present in the genome of H. pylori. This toxic protein when gains access to gastric epithelial cells becomes active through its phosphorylation on tyrosine residues by the host cell kinase. It stimulates cell signaling pathways leading to cytoskeletal changes, epithelial cell proliferation, or cell apoptosis, which if not well regulated may lead to malignant diseases or ulcers [7]. It may also disrupt apical junctional complexes between epithelial cells leading to loss of barrier function [8]. CagA protein may have between 0 and 5 active tyrosine phosphorylation sites. More sites lead to high levels of CagA phosphorylation in epithelial cells [9].

The other virulence protein is vacuolating cytotoxic protein (VacA protein) encoded by the vacuolating cytotoxic gene A (VacA gene) which is present in the genome of all H. pylori strains. The mature secreted VacA protein is polymorphic with variable cytotoxic activity. The toxin is composed of the following regions: the signal peptide region (s) and the intermediate or binding region (m). The signal peptide region is of two types, s1 or s2; s1 type is active and s2 type is inactive. The binding region is also of two types, m1 or m2; m1 type is active and m2 type is less active. VacA protein may comprise any combination of s and m types. Type s1m1 VacA is fully active, and type s1m2 is active but binds to narrower range of cells; type s2m1 and s2m2 do not induce vacuolation [10],[11],[12].

  Materials and methods Top

This study was conducted on 100 Egyptian patients having upper gastrointestinal symptoms and infected with H. pylori documented by stool antigen test [13]. They were subjected to upper gastrointestinal endoscopy to diagnose any associated lesion and take biopsy specimens for microscopic examination [14].

Moreover, 20 patients having positive H. pylori Ag in stool and asymptomatic were included as controls.

Exclusion criteria

The following were the exclusion criteria:
  1. Patients aged above 70 years old.
  2. Patients with hepatic failure.
  3. Patients with renal failure.
  4. Patients with cardiac failure.
  5. Patients with bleeding and/or coagulation disorders.
  6. Patients taking antisecretory drugs.
  7. Patients receiving anti-H. pylori antibiotic or bismuth in the prior 6 months.

An informed consent was obtained from all participants, and the study was carried out in accordance with the code of ethics of the World Medical Association (Declaration of Helsinki).

All of the participants included in the study were subjected to the following:
  1. Full history taking, with particular stress on the following:
    1. Analysis and duration of the complaint (epigastric pain, heartburn, dyspepsia, vomiting, hematemesis, melena, and loss of weight).
    2. History of smoking, drug intake, and any associated diseases.
    3. History of any operations and/or procedures and complications if present.
  2. Complete clinical examination.
  3. Laboratory investigations: routine investigations including complete blood count, fasting blood sugar, renal function tests, liver enzymes, and prothrombin time and activity.
  4. Upper gastrointestinal endoscopy: diagnostic upper gastrointestinal endoscopic examination was done for all participants, and the endoscopic findings were recorded. From these patients, gastric biopsy specimens were taken from the antrum within 2 cm of the pyloric channel for rapid urease test (one tissue biopsy), PCR assay (one tissue biopsy), microbiological examination (three fragments), and histopathological examination (three fragments).

    Endoscopic findings were divided into three categories: nonerosive gastritis, PUDs, and gastric malignancies.
  5. PCR examination includes the following [15]:
    1. DNA extraction.
    2. PCR amplification for detection of H. pylori DNA.
    3. Multiplex PCR to detect H. pylori CagA and VacA genes.
    4. Statistical analysis was performed using SPSS version 18.0 (SPSS Inc., Chicago, Illinois, USA).

Cross tabulation, frequency tables, and χ2-tests were derived to detect association between different variables under study.

  Results Top

Demographic data

Demographic data are presented in [Table 1].
Table 1 Age and sex distribution among cases and controls

Click here to view

Types of H. pylori: by using tissue PCR, H. pylori strains were categorized into three types: type I expressing both CagA and VacA, type II expressed neither CagA nor VacA, and type III expressing CagA only ([Table 2]).
Table 2 Categories of H. pylori strains

Click here to view

The incidence of CagA and VacA genotypes in symptomatic (cases) and asymptomatic patients (controls) is illustrated in [Figure 1].
Figure 1 The incidence of cytotoxin-associated protein A and vacuolating cytotoxic gene A genotypes in symptomatic (cases) and asymptomatic patients (controls).

Click here to view

The incidence of gastroduodenal pathology in CagA only genotype

The incidence of gastroduodenal pathology in CagA only genotype is illustrated in [Figure 1] and [Figure 2] ([Table 3]).
Figure 2 The incidence of gastroduodenal pathology in cytotoxin-associated protein A −only genotype.

Click here to view
Table 3 The incidence of gastroduodenal pathology in CagA only genotype

Click here to view

The incidence of gastroduodenal pathology between CagA only genotype and CagA associated with VacAs1 genotype

The incidence of gastroduodenal pathology in CagA, VacA s1 genotype is illustrated in [Figure 3] ([Table 4]).
Figure 3 The incidence of gastroduodenal pathology in cytotoxin-associated protein A associated with vacuolating cytotoxic gene A s1 genotype.

Click here to view
Table 4 The comparison between the incidence of gastroduodenal pathology between cytotoxin-associated protein A-only genotype and cytotoxin-associated protein A associated with vacuolating cytotoxic gene A s1 genotype

Click here to view

The incidence of gastroduodenal pathology between CagA only genotype and CagA associated with VacAs2 genotype

The incidence of gastroduodenal pathology in CagA associated with VacA s2 genotype is illustrated in [Figure 4] ([Table 5]).
Figure 4 The incidence of gastroduodenal pathology in CagA associated with vacuolating cytotoxic gene A s2 genotype.

Click here to view
Table 5 The comparison between the incidence of gastroduodenal pathology between cytotoxin-associated protein A-only genotype and cytotoxin-associated protein A associated with vacuolating cytotoxic gene A s2 genotype

Click here to view

  Discussion Top

Analysis of demographic data revealed no significant difference between cases and controls in sex distribution, whereas there was a significant difference regarding age. These results were in accordance with those found in developed and developing countries, where it was found that increasing age was associated with increasing risk of H. pylori infection [16].

H. pylori strains differ, and possession of specific virulence factors greatly increases the risk of the disease. The best recognized of these are CagA and VacA proteins.

Based on the analysis of expression of these two virulence factors, isolates of H. pylori were divided into four genotypes: genotype expressing CagA only in 41 (41%) patients, genotype expressing CagA in addition to VacAs1 in 19 (19%) patients, CagA VacA s2 genotype in 34 (34%) patients, and genotype lacking both CagA and VacA in six (6%) patients.

Although much is written in world literature about the frequency and pathogenicity of CagA genotype, little is written about the frequency and pathogenicity of the other three genotypes.

In USA, the prevalence of CagA genotype was 60% [17]. In Europe, its prevalence is 62% in Spain [18] and 68%in England [19]. In Asia, its prevalence was usually over 85% in Japan, Korea, and China [20],[21]. In the Middle East, its prevalence is 71% in Iraq, 78% in Turkey, and 76% in Iran [22],[23].

In Jordan, the CagA genotype was detected in 26.4% [24], whereas Kuwaitis and other Arabian Gulf Arabs had essentially the same prevalence rate of ∼41% [25]. In a study conducted in Israel, CagA genes were present in only 25.5% [26]. The prevalence of CagA positivity in Saudi Arabia was 52% [27].

In this study, CagA genotype was isolated in 41 (41%) patients: 22 (53.7%) patients had gastritis, 15 (36.6%) patients had PUD, and four (9.8%) patients had gastric malignancies. These results are in agreement with many studies [28],[29].

The mosaic structure of VacA represents an important factor in variation of its vacuolating cytotoxin activity. In general, type s1 produce high and moderate levels of toxin activity, whereas s2 strains produce no vacuolating activity. Heterogeneity among VacA alleles may be an important factor in understanding variations in pathogenicity among H. pylori-infected participants [30],[31].

The pathogenicity of VacA in association with CagA genome in the same organism was rarely studied in world literature. In the present study, this genotype was found in 53 (53%) patients, where 19 patients had CagA VacAs1 genotype and 34 patients had CagA VacAs2 genotype.

In the present study, the presence of VacAs1 in association with CagA (CagA VacA s1) increased the toxicity of CagA significantly. In comparison with CagA genotype, PUD incidence was increased from 36.6 to 63.2%, and the incidence of gastric malignancy was increased from 9.8 to 15.8%. In contrast, the association of VacA s2 with CagA genome (CagA VacAs2) decreased the toxicity of CagA genotype. In comparison with CagA genotype, PUD decreased significantly from 36.6 to 20.6%, and the incidence of malignancy was 0% compared with 9.8%. This is explained by the presence of 12-amino-acid hydrophilic amino-terminal segment, present in type s2 but absent from type s1 VacA proteins; this segment slows the capacity of VacA to form membrane channels and abolishes vacuolation.

Particular VacA genotypes have been considered markers for the pathogenicity of individual H. pylori strains, as production of cytotoxin in vitro, epithelial damage in vivo and the development of PUD are related to specific VacA genotypes. The elevated toxicities of s1 strains may contribute to the development of ulcerations. Indeed, VacA s1 strains secrete larger amounts of cytotoxin than VacA s2 strains in vitro, the latter supposedly being less virulent. Indeed, carrying H. pylori with the VacA s1 genotype significantly increased the risk of peptic ulcer or gastric cancer compared with gastritis alone [26],[32].

H. pylori organism lacking both CagA and VacA (CagA negative and VacA negative) can be present in the stomach, causing no lesion. This was found in 80%% of the controls (16 out of 20 participants) and 6% of patients (6 out of 100). This can explain that most H. pylori infected participants are asymptomatic.

  Conclusion Top

Patients with CagA positive genotype but Vac A negative are prone to develop PUD in 36.6% and gastric malignancies in 9.8% of cases.
  1. The association of VacAs1 with CagA increases significantly the toxicity of CagA. Patients are prone to develop PUD (≥63.2%) and gastric malignancies (≥15.8%).
  2. The presence of s2 with CagA decreases significantly the toxicity of CagA. The patients are prone to develop PUD in only 20.6% of patients with no malignancy.
  3. Patients with CagA-negative and VacA-negative strains are rarely prone to develop gastroduodenal pathology.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Rust M, Schweinitizer T, Josenhans C. Helicobacter Flagella, motility and chemostaxis. Yamaoka Y, DeBakey ME, editors. Helicobacter pylori: Molecular Genetics and Cellular Biology. TX, USA: Caister Academic Press; 2008. ISBN: 978-1-904455-31-8  Back to cited text no. 1
Lehours P, Yilmaz O. Epidemiology of Helicobacter pylori infection. Helicobacter 2007; 12:1–3.  Back to cited text no. 2
Montecucco C, Rappuoli R. Living dangerously: how Helicobacter pylori survives in human stomach. Nat Rev Mol Cell Biol 2001; 2:457–466.  Back to cited text no. 3
Kindermann A, Lopes AI. Helicobacter pylori infection in pediatrics. Helicobacter 2009; 14:52–57.  Back to cited text no. 4
Yamaoka Y. Roles of the plasticity regions of Helicobacter pylori in gastroduodenal pathogenesis. J Med Microbiol 2008; 57:545–553.  Back to cited text no. 5
Peek RMJr, Blaser MJ. Helicobacter pylori and gastrointestinal tract adenocarcinomas. Nat Rev Cancer 2002; 2:28–37.  Back to cited text no. 6
Li Q, Liu J, Gong Y, Yuan Y. Association of CagA EPIYA-D or EPIYA-C phosphorylation sites with peptic ulcer and gastric cancer risks: a meta-analysis. Medicine (Baltimore) 2017; 96:e6620.  Back to cited text no. 7
Ameiva MR, Vogelmann R, CoVacci A, Tompkins LS, Nelson WJ, Falkow S. Disruption of the epithelial apical–junctional complex by Helicobacter pylori CagA. Science 2003; 300:1430–1434.  Back to cited text no. 8
Argent RH, Kidd M, Owen RJ, Thomas RJ, Limb MC, Atherton JC. Determinants and consequences of different levels of Cag A phosphorylation for clinical isolates of Helicobacter pylori. Gatroenterology 2004; 127:514–523.  Back to cited text no. 9
Foegeding NJ, Caston RR, McClain MS, Ohi MD, Cover TL. An overview of Helicobacter pylori VacA toxin biology. Toxins (Basel) 2016; 8:17.  Back to cited text no. 10
Letley DP, Rhead JL, Twells RJ, Dove B, Atherton JC. Determinants of non-toxicity in the gastric pathogen Helicobacter pylori. J Biol Chem 2003; 278:26734–26741.  Back to cited text no. 11
Rhead JL, Letley DP, Mohammadi M, Hussein N, Mohagheghi MA, Eshagh Hosseini M et al. A new Helicobacter pylori vacuolating cytotoxin determinant, the intermediate region is associated with gastric cancer. Gastroenterology 2007; 133:926–936.  Back to cited text no. 12
Veijola L, Myllyluoma E, Korpela R, Rautelin HH. Stool antigen test in the diagnosis of Helicobacter pylori infection before and after eradication therapy. World J Gastroenterol 2005; 11:7340–7344.  Back to cited text no. 13
Vaira D, Gatta L, Ricci C, Miglioli M. Diagnosis of Helicobacter pylori infection. Aliment Pharmacol Ther 2002; 16:16–23.  Back to cited text no. 14
Kabir S. Detection of Helicobacter pylori DNA in faeces and saliva by polymerase chain reaction: a review. Helicobacter 2004; 9:115–123.  Back to cited text no. 15
Pilotto A, Franceschi M. Helicobacter pylori infection in older people. World J Gastroenterol 2014; 20:6364–6373.  Back to cited text no. 16
Bonequi P, Meneses-González F, Correa P, Rabkin CS, Camargo MC. Risk factors for gastric cancer in Latin-America: a meta-analysis. Cancer Causes Control 2013; 24:217–231.  Back to cited text no. 17
Lorenzo I, Fernández-de-Larrea N, Michel A, Romero B, Lope V, Bessa X et al. Helicobacter pylori seroprevalence in Spain: influence of adult and childhood sociodemographic factors. Eur J Cancer Prev 2019;28(4):294–303.  Back to cited text no. 18
Kauser F, Khan AA, M. Hussain A, Carroll M, Ahmad N et al. The cag pathogenicity Island of Helicobacter pylori is disrupted in the majority of patient isolates from different human populations. J Clin Microbiol 2004; 42:5302–5308.  Back to cited text no. 19
Chen XJ, Yan J, Shen YF. Dominant CagA/VacA genotypes and coinfection frequency of H. pyloriin peptic ulcer or chronic gastritis patients in Zhejiang Province and correlations among different genotypes, coinfection and severity of the diseases. Chin Med J (Engl) 2005; 118:460–466.  Back to cited text no. 20
Erzin Y, Koksal V, Altun S, Dobrucali A, Aslan M, Erdamar S et al. Prevalence of H. pyloriVacA, CagA, CagE, iceA, and babA2 genotypes and correlations with clinical outcomes in Turkish patients with dyspepsia. Helicobacter 2006; 11:574–580.  Back to cited text no. 21
Saribasak H, Salih BA, Yamaoka Y, Sander E. Analysis of Helicobacter pylori genotypes and correlation with clinical outcome in Turkey. J Clin Microbiol 2004; 42:1648–1651.  Back to cited text no. 22
Hussein NR, Mohammadi M, Talebkhan Y, Doraghi M, Letley DP, Muhammad MK et al. Differences in virulence markers between Helicobacter pylori strains from Iraq and those from Iran: potential importance of regional differences in H. pylori-associated disease. J Clin Microbiol 2008; 46:1774–1779.  Back to cited text no. 23
Nimri LF, Matalka I, Bani Hani K, Ibrahim M. Helicobacter pylorigenotypes identified in gastric biopsy specimens from Jordanian patients. BMC Gastroenterol 2006; 6:27.  Back to cited text no. 24
Al Qabandi A, Mustafa AS, Siddique I, Khajah AK, Madda JP, Junaid TA. Distribution of VacA and CagA genotypes of Helicobacter pylori in Kuwait. Acta Trop 2005; 93:283–288.  Back to cited text no. 25
Benenson S, Halle D, Rudensky B, Faber J, Schlesinger Y, Branski D et al. Helicobacter pylori genotypes in Israeli children: the significance of geography. J Pediatr Gastroenterol Nutr 2002; 35:680–684.  Back to cited text no. 26
Momenah AM, Tayeb MT. Helicobacter pyloriCagA and iceA genotypes status and risk of peptic ulcer in Saudi patients. Saudi Med J 2007; 28:382–385.  Back to cited text no. 27
Palli D, Masala G, Del Giudice G, Plebani M, Basso D, Berti D et al. CagA Helicobacter pylori infection and gastric cancer risk in the EPIC-EURGAST study. Int J Cancer 2007; 120:859–867.  Back to cited text no. 28
Atherton JC. H. pylorivirulence factors. Br Med Bull 1998; 54:105–120.  Back to cited text no. 29
Atherton JC, Cao P, Peek RM, Tummuru MK, Blaser MJ, Cover TL. Mosaicism in vacuolating cytotoxin alleles of Helicobacter pylori − association of specific VacA types with cytotoxin production and peptic ulceration. J Biol Chem 1995; 270:17771–17777.  Back to cited text no. 30
Da Costa DM, Pereira Edos S, Rabenhorst SH. What exists beyond CagA and VacA? Helicobacter pylori genes in gastric diseases. World J Gastroenterol 2015; 21:10563–10572.  Back to cited text no. 31
Sugimoto M, Yamaoka Y. The association of VacA genotype and Helicobacter pylori-related disease in Latin American and African populations. Clin Microbiol Infect 2009; 15:835–842.  Back to cited text no. 32


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]


Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

  In this article
Materials and me...
Article Figures
Article Tables

 Article Access Statistics
    PDF Downloaded19    
    Comments [Add]    

Recommend this journal