A simple multiplex PCR assay for diagnosing virulent Helicobacter pylori infection in human gastric biopsy specimens from subjects with gastric carcinoma and other gastro-duodenal diseases

Prevalence, Virulence Genes, Phylogenetic Analysis, and Antimicrobial Resistance Profile of Helicobacter Species in Chicken Meat and Their Associated Environment at Retail Shops in Egypt

Helicobacter pylori (H. pylori) and Helicobacter pullorum (H. pullorum) are frequently reported pathogens in humans and poultry, respectively. Nevertheless, the source of H. pylori is still unclear. This study aimed to detect Helicobacter spp. in chicken carcasses and to assess the antibiogram and the virulence genes of Helicobacter isolates. Three hundred chicken meat samples (100 each of chicken breast, liver, and gizzard), besides 60 swab samples from chicken processing surfaces, were collected from retail shops in Qalyubia Governorate, Egypt, and examined for the prevalence of H. pylori and H. pullorum. The 16S rRNA of three H. pylori and two H. pullorum isolates were sequenced to determine the genetic relationship between these two Helicobacter spp. Of the 300 chicken samples tested, 16 (5.33%) and 14 (4.67%) were positive for H. pylori and H. pullorum, respectively. Multiplex PCR revealed that the virulence genes vacuolating cytotoxin A (vacA)s1, cytotoxin-associated gene A (cagA), and restriction endonuclease-replacing gene A (hrgA) were detected in 66.7%, 77.8%, and 100% of H. pylori strains tested, respectively. H. pylori showed the highest resistance for clarithromycin, while H. pullorum exhibited the highest resistance towards erythromycin and ciprofloxacin. The study concluded that the chicken meat and giblets are potential sources of the virulent and antimicrobial-resistant strains of H. pylori of human origin.

Antiulcer activity of ethanolic leaf extract of Capparis zeylanica against chemically induced ulcers

Background

Peptic ulcer is the term which refers to acid peptic injury of the digestive tract, and it results in mucosal break reaching the submucosa. Leaves of Capparis zeylanica are used as counterirritant, rubefacient, as a cataplasm in piles, boils and swellings. The objective of the present study was to evaluate the antiulcer activity of C. zeylanica ethanolic extract against chemically induced ulcers. The leaves were extracted with ethanol (50%) as solvent using hot perforation method. The extract was evaluated against acute and chronic ulcer models. Further, extract was evaluated for gastric autopsy of animals infected with Helicobacter pylori bacteria. The genes of rats were evaluated by gel electrophoresis method. Morphology of stomach was also studied after treatment with plant extract.

Results

Results exhibited that the area of ulcer was significantly reduced in both acute [naproxen-induced ulcer model (3.62 mm2), histamine-induced ulcer model (3.2 mm2) and ethanol-induced ulcer model (106.4 mm2)] and chronic [chronic naproxen-induced ulcer model (2.14 mm2), chronic histamine-induced ulcer model (0.16 mm2)]. The animals of naproxen-induced ulcer infected with H. pylori showed 91.48% reduction of ulcer area on 9th week after treatment with C. zeylanica extract (360 mg/kg). The rapid urease test and DNA observation revealed that no infection was present from 4th week after treatment with C. zeylanica extract (480 mg/kg). Morphological studies showed less conspicuous petechial marks and hemorrhages in stomach tissues after treatment with test drugs. Histopathological study revealed that C. zeylanica extract reduced stomach damages and eradicated H. pylori infections.

Conclusion

It can be concluded from the study that C. zeylanica possess antiulcer and anti-helicobacter activities.

CagE, cagA and cagA 3' region polymorphism of Helicobacter pylori and their association with the intra-gastric diseases in Moroccan population

Helicobacter pylori infection is the most important etiological factor in gastroduodenal diseases development. Its evolution is influenced by several factors, including bacterial virulence genes such as cagA and cagE. This work aimed to evaluate the predictive value of cagE alone and in combination with cagA and CagA-EPIYA-C motifs number as a marker of the infection evolution. A total of 823 H. pylori DNA extracted from biopsies of consenting patients suffering from gastritis, peptic ulcer, or gastric cancer. The cagE, cagA status and cagA 3' region polymorphism were determined by PCR. The analysis shows that the risk of duodenal ulcer is 1.97-fold higher (CI = 1.18-3.30) in patients infected by strains cagA+/cagE+. And the risk of gastric cancer is 5.19-fold higher (CI = 1.18-22.70) in patients harboring strains cagE+/2EPIYA-C. The results suggest that cagE in combination with cagA-EPIYA-C motifs number can be used as predictive biomarker of H. pylori infection evolution.

Helicobacter pylori cagE, cagG, and cagM can be a prognostic marker for intestinal and diffuse gastric cancer

It is known that Helicobacter pylori is the main cause of peptic ulceration and gastric cancer. However, there is a lack of information on whether H. pylori strains may differ in gastric cancer histological subtypes. This study aimed to investigate different H. pylori strains considering six cag Pathogenicity Island - cagPAI genes (cagA, cagE, cagG, cagM, cagT, and virb11), and vacuolating cytotoxin - vacA alleles, and their relation to gastric cancer histologic subtypes. For this purpose, tumor samples from 285 patients with gastric carcinoma were used. H. pylori infection and genotypes were determined by polymerase chain reaction (PCR). H. pylori was detected in 93.9% of gastric tumors. For comparative analyzes between histopathological subtypes considering H. pylori cagPAI genes the strains were grouped according to the vacA s1/s2 alleles. In the vacAs1 group, the strains cagA(-)cagE(+), cagA(+)cagE(+)cagG(+), cagA(+)cagM(+), or only cagE(+) strains were more frequent in the intestinal subtype (P = .009; P = .024; P = .046, respectively). In contrast, cagM(+)cagG(+)cagA(-) and cagE(-) were associated with diffuse tumors (P = .036), highlighting the presence of cagE in the development of intestinal tumors, and the presence of cagG and absence of cagE in diffuse tumors. Furthermore, WEKA software and Decision Tree (CART) analyses confirmed these findings, in which cagE presence was associated with intestinal tumors, and cagE absence and cagG(+) with diffuse tumors. In conclusion our results showed that vacAs1 (cagG + cagM) strains, mainly cagG positive with cagE absence, were relevant in the studied population for the diffuse outcome, while the presence of cagE was relevant for the intestinal outcome. These findings suggest the relevance of these H. pylori genes as potential markers for gastric cancer histological outcomes.

Gene expression patterns of COX-1, COX-2 and iNOS in H. Pylori infected histopathological conditions

BACKGROUND

Research indicates that Helicobacter pylori can inflict severe histological damage through the modulation of host-related genes. The current study investigated the effect of H. pylori genotypes in the outcome of disease, and the expression of anti-apoptotic related genes, COX-1, COX-2, and iNOS genes in benign, pre-malignant, and malignant lesions of gastric carcinogenesis.

MATERIALS AND METHODS

Tissue samples from H. pylori positive patients were graded based on the genotype of the infected H. pylori strain. Expression of COX-1, COX-2 and iNOS was assessed using a combination of real-time PCR and immunohistochemistry.

RESULTS

Gene expression studies confirmed that COX-2 and iNOS expression was highly and selectively induced in epithelium with premalignant changes such as atrophic conditions, metaplasia and dysplasia, suggesting an important role of these genes in the sequence to gastric carcinoma of the intestinal type. Furthermore, the expression of COX-2 and iNOS was also dependent on the genotype of H. pylori and subjects with genotype-1 exhibited significantly higher expressions of COX-2 and iNOS compared to other genotypes. Comparison of the expression levels among infected and uninfected individuals demonstrated significant difference in the expression pattern of COX-2 gene whereas iNOS expression was found only in subjects infected H. pylori (p < 0.001). Immunohistochemical staining showed 1.5619 folds higher propensity of COX-2 and 3.2941 folds higher intensity of iNOS expression in subjects infected with H. pylori genotype 1.

CONCLUSION

The up-regulation of COX-2 and iNOS was associated with the genotype of the H. pylori strain and the presence of certain genotype may greatly affect early events during carcinogenesis.

Helicobacter pylori vacA, cagA and iceA genotypes in dyspeptic patients from southwestern region, Saudi Arabia: distribution and association with clinical outcomes and histopathological changes

Background

The aim of this study was to identify the common H. pylori virulence genes among dyspeptic Southwestern Saudi patients and their association with clinical outcomes and histopathological findings to help practitioners and researchers in the region for better management of infections caused by such bacteria.

Methods

Four hundred two gastric biopsy specimens were analyzed using histopathological examination and real time-PCR. The positive 187 specimens by RT-PCR were genotyped using PCR targeting cagA, vacA and iceA genes.

Results

One hundred twenty-eight gastric biopsy specimens were positive in genotyping PCRs. The cagA, vacA, iceA1 and iceA2 genes were detected in rates of 49.2% (63/128), 100%(128/128), 42.2% (54/128), 32.8% (42/128), respectively. The vacA s1as1bm2 subtype was the highest 23.4% (30/128), followed by m2 and s1a1b subtypes which were equally detected [16.4% (21/128) for each]. The iceA genes were significantly associated with gastritis and gastric ulcer. Overall, vacA genotypes were significantly associated with gastritis, gastric and duodenal ulcers. The vacA subtypes: s1as1bm2, s1a1b and s2 m2 showed chronic active gastritis in percentages of 90.0, 81, and 84.2%, respectively. All vacA mixed genotypes showed chronic active gastritis.

Conclusions

H. pylori virulence genes are highly prevalent and diverse among patients with dyspepsia in Southwestern region of Saudi Arabia. The iceA genes and the different vacA subtypes are significantly associated with the clinical outcomes and histopathological changes especially chronic active gastritis.

Role of Plasticity Region Genes and cagE gene of cagPAI of Helicobacter pylori in Development of Gastrointestinal (GI) Diseases

Backround::

Helicobacter pylori is a Gram-negative, micro aerophilic bacterium in the human stomach that is associated with the development of gastrointestinal ailments such as peptic ulcer (PU) and gastric cancer (GC). In the present study, plasticity region genes (jhp0940, jhp0945 and jhp0947) and and cagE gene of cag PAI were assessed independently and in combination for their ability to predict clinical consequences.

Materials and Methods::

A total of 211 strains which were isolated from patients with different gastrointestinal diseases (114 with non-atrophic gastritis, 59 with PU, and 38 with GC) were genotyped by PCR and sequencing. Data were collected and analyzed using SPSS software version 19. Logistic regression models were applied to determine relationships between the plasticity region genes and cagE of H.pylori and clinical status.

Results::

The cagE gene (71.1%) had the highest frequency and jhp0945 (13.7%) was the least abundant among the genes examined. The jhp0940 gene was significantly associated with GC (P = 0.0007), but not PU. On multiple logistic regression analysis, adjusted for both age and sex, the jhp0940 genotype was significantly associated with GC (odds ratio, OR = 2.8, 95%CI = 1.1–7.0; P = 0.027). The jhp0940+/ jhp0945+/jhp0947+ genotype was also linked to an increased risk of GC (OR = 50.4, 95%CI = 5.1–500.0; P = 0.0008) while no genotype correlation was found with PU in Iran (P > 0.05).

Conclusions::

Given the high frequency of cagE, this gene could be a suitable marker for the presence of cag PAI in Iranian strains. The jhp0940 genotype could also be a strong predictor of GC in Iran.

Helicobacter pylori overcomes natural immunity in repeated infections

Repeated experimental reinfection of two subjects indicates that Helicobacter pylori infection does not promote an immune response protective against future reinfection. Our results highlight the importance of preventing reinfection after eradication, through public health initiatives, and possibly treatment of family members. They indicate difficulties for vaccine development, especially therapeutic vaccines.

In vitro anti-Helicobacter pylori activity of a flavonoid rich extract of Glycyrrhiza glabra and its probable mechanisms of action

ETHNOPHARMACOLOGICAL RELEVANCE

Glycyrrhiza glabra Linn. is regarded useful for peptic ulcer in traditional systems of medicine in India and Helicobacter pylori has been considered as one of the causative factors for peptic ulcer. Aim of the present study is to evaluate the anti-Helicobacter pylori action of GutGard(®), a flavonoid rich extract of Glycyrrhiza glabra and further to elucidate the possible mechanisms of its anti-Helicobacter pylori action.

MATERIALS AND METHODS

Agar dilution and microbroth dilution methods were used to determine the minimum inhibitory concentration of GutGard(®) against Helicobacter pylori. Protein synthesis, DNA gyrase, dihydrofolate reductase assays and anti-adhesion assay in human gastric mucosal cell line were performed to understand the mechanisms of anti-Helicobacter pylori activity of GutGard(®).

RESULTS

GutGard(®) exhibited anti-Helicobacter pylori activity in both agar dilution and microbroth dilution methods. Glabridin, the major flavonoid present in GutGard(®) exhibited superior activity against Helicobacter pylori while glycyrrhizin did not show activity even at 250 μg/ml concentration. In protein synthesis assay, GutGard(®) showed a significant time dependent inhibition as witnessed by the reduction in (35)S methionine incorporation into Helicobacter pylori ATCC 700392 strain. Additionally, GutGard(®) showed a potent inhibitory effect on DNA gyrase and dihydrofolate reductase with IC(50) value of 4.40 μg/ml and 3.33 μg/ml respectively. However, the extract did not show significant inhibition on the adhesion of Helicobacter pylori to human gastric mucosal cell line at the tested concentrations.

CONCLUSION

The present study shows that, GutGard(®) acts against Helicobacter pylori possibly by inhibiting protein synthesis, DNA gyrase and dihydrofolate reductase.

Relevance of Helicobacter pylori genotypes in gastric pathology and its association with plasma malondialdehyde and nitric oxide levels

Persistent infection with Helicobacter pylori confers an increased risk of peptic ulceration and gastric adenocarcinoma. Reactive oxygen and nitrogen species play a crucial role in the progression from normal gastric mucosa to cancer. The aim of the present study was to investigate the plasma malondialdehyde and nitric oxide levels in H. pylori related gastroduodenal diseases and associate their levels with gastric pathology and genotypes of H. pylori. Malondialdehyde and nitric oxide levels in plasma samples of 250 subjects were spectrophotometrically determined. Subsequently, genotypic and histopathological assessment was performed in gastric biopsies obtained during endoscopy. The levels of MDA and NO exceeded in subjects infected with genotype-1 of Hp than those with other genotypes suggesting more precise interaction of highly virulent strains of Hp in eliciting severe tissue damage. In conclusion, the study demonstrates close relationship between the plasma malondialdehyde and nitric oxide levels, gastric histopathology and genotypes of H. pylori.

DNA signature-based approaches for bacterial detection and identification

During the late eighties, environmental microbiologists realized the potential of the polymerase chain reaction (PCR) for the design of innovative approaches to study microbial communities or to detect and identify microorganisms in diverse and complex environments. In contrast to long-established methods of cultivation-based microbial identification, PCR-based techniques allow for the identification of microorganisms regardless of their culturability. A large number of reports have been published that describe PCR-inspired methods, frequently complemented by sequencing or hybridization profiling, to infer taxonomic and clonal microbial diversity or to detect and identify microorganisms using taxa-specific genomic markers. Typing methods have been particularly useful for microbial ecology-driven studies; however, they are not suitable for diagnostic purposes, such as the detection of specific species, strains or clones. Recently, comprehensive reviews have been written describing the panoply of typing methods available and describing their advantages and limitations; however, molecular approaches for bacterial detection and identification were either not considered or only vaguely discussed. This review focuses on DNA-based methods for bacterial detection and identification, highlighting strategies for selecting taxa-specific loci and emphasizing the molecular techniques and emerging technological solutions for increasing the detection specificity and sensitivity. The massive and increasing number of available bacterial sequences in databases, together with already employed bioinformatics tools, hold promise of more reliable, fast and cost-effective methods for bacterial identification in a wide range of samples in coming years. This tendency will foster the validation and certification of these methods and their routine implementation by certified diagnostic laboratories.