scholarly journals Determination of Helicobacter pylori Virulence Genes in Gastric Biopsies by PCR

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Tamer Essawi ◽  
Wail Hammoudeh ◽  
Israr Sabri ◽  
Walid Sweidan ◽  
Mohammad A. Farraj

Aim. The aim of this study was to identify the presence of H. pylori in biopsy specimens from symptomatic patients by PCR. In addition, the rate of cagA, vacA, iceA1, and iceA2 virulence genes was determined. Materials and Methods. One hundred antral gastric biopsy specimens were collected during endoscopy from patients suffering from gastroduodenal symptoms. The samples were collected by the gastroenterologists in their own clinics in Ramallah, Palestine. DNA was extracted from the biopsies and subsequently used for PCR identification of H. pylori and the virulence genes using specific primers. Results. The rate of positive H. pylori in the collected biopsies was 44%. The rates of the virulence genes in this sample: cagA, vacA, iceA1, and iceA2 were 65.9%, 40.9%, 63.6%, and 84.1%, respectively. Conclusion. The iceA2 gene was the most frequent in this study. Much research is necessary to determine the presence of an association of this gene with gastric pathology. Variation in the rates of the iceA gene in different countries is a strong indication of its geographical distribution. This study would provide important information regarding the prevalence of virulence genes (vacA, cagA, iceA1, and iceA2) in H. pylori strains in the sample tested in this country.

2017 ◽  
Vol 54 (3) ◽  
pp. 217-221 ◽  
Author(s):  
Myriam Lucrecia MEDINA ◽  
Marcelo Gabriel MEDINA ◽  
Luis Antonio MERINO

ABSTRACT BACKGROUND: The clinical outcome of Helicobacter pylori infection has been associated with virulence factors. The presence of these factors is useful as molecular markers in the identification of the high risk for developing severe gastric pathologies. OBJECTIVE: To correlate the presence of virulence markers cagA and bab2A of H. pylori in oral and gastric biopsy samples. METHODS: An observational, prospective, descriptive, and cross-sectional study was carried out between September 2011 and September 2012. Patients suffering dyspepsia with indication for upper gastrointestinal video endoscopy who attended the Gastroenterology Service of the Hospital Dr. Julio C. Perrando were included. Epidemiological investigation was completed. To detect the bacteria and their virulence genes, samples of saliva, dental plaque and gastric biopsy were taken and processed by PCR. RESULTS: Sixty-one patients were selected for this study (30 women and 31 men). H. pylori was detected in 31 gastric biopsies and 31 oral samples. Significant difference between oral and gastric samples was found in cagA genotype. Agreement between oral and gastric genotypes was found in 38.7% of samples from the same patient. CONCLUSION: This study is the first in provide information about the genotypes of the Argentinean Northeast H. pylori strains. Despite the high prevalence of H. pylori infection, the most of patients had less virulent genotypes in oral cavity and gastric tissue. The cagA / babA2 combination was not frequent in the samples studied. There was not a statistical correlation between the virulence genes and gastroduodenal or oral diseases. Although in some patients the same genotype was found both in oral and gastric samples, it cannot be ensure that they corresponding to the same strain because a DNA sequencing was not performed.


2005 ◽  
Vol 51 (7) ◽  
pp. 569-573 ◽  
Author(s):  
Fusun Can ◽  
Zerrin Yilmaz ◽  
Muge Demirbilek ◽  
Banu Bilezikci ◽  
Ganiye Kunefeci ◽  
...  

A reliable diagnostic test for Helicobacter pylori is important in clinical practice and research. The ideal diagnostic test for H. pylori should be sensitive, specific, and cost-effective. Helicobacter pylori resistance to clarithromycin is a common reason for failure of eradication therapy. The aim of this study was to evaluate the fluorescent in situ hybridization (FISH) method to detect H. pylori and determine clarithromycin resistance in formalin-fixed, paraffin-embedded gastric biopsy specimens. One hundred seventeen gastric biopsy specimens from patients with dyspepsia were examined for the presence of H. pylori by conventional culture, FISH, and histopathological methods. A set of fluorescent-labeled oligonucleotide probes binding to either H. pylori 16S rRNA or 23S rRNA sequences were used for FISH analysis. Phenotypic antibiotic susceptibilities of the isolates were tested using the Epsilometer test method (E test). Helicobacter pylori was detected in 70 of 117 biopsy specimens by histopathological examination and FISH, whereas it was detected in 47 specimens by culturing. Histopathology and FISH techniques failed to identify H. pylori in 1 biopsy sample isolated by culture. Clarithromycin resistance was found in 11 of 46 H. pylori isolates using the E test method. All of the phenotypic resistance measurements of isolates were correlated with genotypic clarithromycin resistance. Eleven clarithromycin-resistant strains were identified by FISH. The diagnosis of H. pylori infection and the determination of clarithromycin resistance in formalin-fixed, paraffin-embedded specimens using FISH is promising because it provides a rapid, reliable, and culture-independent diagnosis.Key words: Helicobacter pylori, clarithromycin resistance, FISH.


2019 ◽  
Vol 19 (3) ◽  
pp. 274-278 ◽  
Author(s):  
Saba Fakhrieh Asl ◽  
Mehrnaz Pourvahedi ◽  
Ali Mojtahedi ◽  
Mohammad Shenagari

Objective:Helicobacter pylori is a Gram-negative bacterium which has a serious effect on up to half of the world’s population and has been related to different gastric diseases. The goal of this study was to assess the frequency of babA, cagE and cagA genotypes among H. pylori strains isolated from gastric biopsies of endoscopic patients in the north of Iran.Methods:The present study was performed on 90 strains of H. pylori isolated from patients with gastric diseases (Gastric ulcer (GU), Duodenal ulcer (DU), Gastritis (G), Non-ulcer dyspepsia (NUD) and Gastric adenocarcinoma (GC)). DNA was extracted from all isolated strains and PCR method was performed to detect the prevalence of babA2, cagE and cagA genes using specific primers.Results:Among 90 samples of H. pylori, babA2, cagE, and cagA genes were detected in 42.2%, 30% and 82.2% of strains respectively. The statistical analysis showed that the prevalence of cagA gene in GU, G, DU, and NUD was significantly higher than other genes. Moreover, cagA, and babA2 genes were significantly more prevalent in GC patients compared to cagE gene. Our isolates exhibited 8 distinct arrangements of virulence patterns. The occurrence of cagA (35.6%) was the most prevalent pattern followed by cagA/babA2 (20%) and cagA/babA2/cagE (14.4%).Conclusion:In summary, as first report from Guilan province in the north of Iran, we showed significant association between the presence of babA2, cagE, and cagA genes in different types of gastric disorders.


2019 ◽  
Vol 7 (19) ◽  
pp. 3211-3215
Author(s):  
Wafaa Redha Mohammed Al-Sabbagh ◽  
Alaa Qasim Yahya ◽  
Rasha Abdelraouf Alsafi

BACKGROUND: Helicobacter pylori is an important gastrointestinal infective bacteria with many serious complications including gastric erosions and ulceration, duodenal ulcer, gastric carcinoma and MALT gastric lymphoma. The gastric biopsy is commonly performed in H. pylori-positive dyspeptic individuals, and many previous researchers studied the histopathological features of infected gastric biopsies however little previous studies focused on the histopathological findings in young population in comparison to the older one. AIM: To make a focus on the histopathological effects of H. pylori infection in young patients compared with the older one and predicts the need for endoscopy in this population, also to estimates the prevalence of infection in Iraqi patients. MATERIAL AND METHODS: the sample for this study is 180 patients in total, they attended Marjan medical city in Iraq for dyspepsia of more than 3 months and prepared for OGD. Patients asked for their permission to do immunological tests for H. pylori. Both serology for H. pylori antibodies and stool for antigen tests are used, and the case is included in the study only if both tests were positive, after OGD, the gastric biopsies are processed and examined histopathologically. RESULTS: Normal gastric biopsy is the most common histopathological finding in young (< 25 years) patients (75%) while chronic atrophic gastritis is the most common one in patients > 25 years age (57%). The prevalence of Helicobacter pylori infection in dyspeptic patients was 73.3%, the correlation between infection and sex was insignificant (p-value 0.06), and no significant correlation between infection and age (p-value 0.07) was concluded. CONCLUSION: H. pylori-related histopathological changes of gastric mucosa in young (< 25 years) are commonly mild and does not necessitate endoscopy at this age unless there are alarming signs.


2000 ◽  
Vol 14 (4) ◽  
pp. 277-282 ◽  
Author(s):  
Masahiro Yoshinaga ◽  
Akira Ohtani ◽  
Satoru Tsuruta ◽  
Tetsuya Kato ◽  
Eishi Higashi ◽  
...  

BACKGROUND: Recent studies have shown that acid-suppressive therapy increases the severity ofHelicobacter pylori- associated gastritis in the corpus.PURPOSE: To evaluate interleukin (IL)-8 production in the gastric corpus mucosa before and during acid-suppressive therapy inH pylori-infected patients.PATIENTS AND METHODS: Ten patients with reflux esophagitis (fiveH pylori-positive and fiveH pylori-negative) were treated with omeprazole 20 mg. Serum gastrin concentrations,H pyloricolonization density and mucosal IL-8 levels in the corpus were investigated at entry and two weeks after starting therapy. IL-8 levels were measured by ELISA. The organism density was determined, and scored according to area occupied by the bacterial colonies. The presence ofH pyloriwas assessed by rapid urease testing and histological finding of gastric biopsy specimens.RESULTS: InH pylori-positive patients, concentrations of IL-8 during therapy significantly exceeded those before therapy (36.2±6.8 versus 18.3±3.8 pg/mg protein; P<0.05) without alteringH pyloridensity. InH pylori-negative patients, IL-8 levels were similar before and during therapy (6.1±2.7 versus 6.3±3.0 pg/mg protein). Concentrations of gastrin during therapy were significantly higher than those before therapy in all patients.CONCLUSIONS: The results suggest that acid suppression increases mucosal IL-8 levels inH pylori-infected patients with reflux esophagitis.


1998 ◽  
Vol 12 (4) ◽  
pp. 295-298 ◽  
Author(s):  
Diane E Taylor ◽  
Qin Jiang ◽  
Richard N Fedorak

The incidence of antibiotic resistance to amoxicillin, clarithromycin, erythromycin, metronidazole and tetracycline inHelicobacter pyloristrains isolated from gastric biopsy specimens obtained in Alberta was investigated. Results for all antibiotics were obtained using agar dilution, and in addition to metronidazole, the E test was used. Resistance to amoxicillin and tetracycline was not detected. Metronidazole resistance determined using agar dilution was approximately 12% (95% CI 4% to 26%) when minimal inhibitory concentrations (MICs) were at least 8 µg/mL, but fell to 2% (95% CI 0.1% to 13%) when MICs were set at 32 µg/mL or greater. The E test for metronidazole resistance (MIC 8 µg/mL or greater) yielded a slightly higher percentage of resistant strains compared with agar dilution tests (14%, 95% CI 5% to 29%). One of the 31 strains was resistant to clarithromycin (MIC 8 µg/mL) and erythromycin (MIC 16 µg/mL). Thus, the incidence of resistance to clarithromycin, part of the currently used triple therapy for eradication ofH pylori, was 3% (95% CI 0.1% to 17%).


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Nicoline F. Tanih ◽  
Roland N. Ndip

Rapid diagnosis and treatment ofHelicobacter pylori(H. pylori) presents a challenge. We aimed at investigating the presence ofH. pylori, susceptibility profile, and associated mutations in an effort to validate the effectiveness of GenoType HelicoDR assay inH. pylorityping in our environment. Two hundred and fifty-four biopsy specimens were cultured and DNA extracted from seventy-eight positive cultures using the Qiagen DNA extraction kit. The GenoType Helico DR which employs reverse hybridisation was used to confirm the presence ofH. pylori, determination of its susceptibility to antimicrobials, and detection of mutations conferring resistance to clarithromycin and fluoroquinolones. The organism was isolated from 168/254 (66.1 %) of the specimens by culture. Of the 78 strains used for further investigation, 12/78 (15.38%) were resistant to clarithromycin while 66/78 (84.61%) were susceptible. For fluoroquinolone, 70/78 (89.74%) strains were susceptible while 8 (10.26%) were resistant. Mutations were observed in 17 strains with A2147G being the most prevalent; A2146C and D91N were the least. The reverse hybridisation assay is an easy and fast technique in confirming the presence ofH. pylori, its antimicrobial profile, and associated mutations. Analysis regarding the suitability of this assay forH. pylorityping is warranted in other regions.


2021 ◽  
Author(s):  
Esraa Osman ◽  
Maram M. Elnosh ◽  
Aalaa Mahgoub Albasha ◽  
Amira A M Fadl ◽  
Luai Osman Ibrahim Marouf ◽  
...  

Abstract ObjectivesHelicobacter pylori cytotoxin-associated gene pathogenicity island (cag-PAI) is one of the strain-specific genes (they do not exist in all strains). cag-PAI is involved in inducing inflammation, ulceration, and carcinogenesis. This study aimed to detect and characterize cagA and cagE virulence genes among H. pylori strains from Sudanese patients with gastric discomfort.ResultOut of 288 gastric biopsies screened for the presence of H. pylori, 34% (98/288) were positive, cagA gene was present in 41% (40/98) of specimens, mostly in patients with gastritis 72.5% (29/40), followed by duodenal ulcer 15% (6/40), esophagitis 5% (2/40), and 7.5% (3/40) in patients diagnosed normal by endoscopy. cagE gene was present in 39% (38/98) of specimens, the majority 73.7% (28/38) were from patients with gastritis, 10.5% (4/38) duodenal ulcer, 5.3% (2/38) esophagitis, 2.6% (1/38) gastric ulcer, and 7.9% (3/38) were diagnosed as normal. The cagA and cagE protein sequences have synonymous amino acid variations.


2005 ◽  
Vol 62 (1) ◽  
pp. 39-43 ◽  
Author(s):  
Tatjana Babic ◽  
Hakija Basic ◽  
Biljana Selimovic-Miljkovic ◽  
Branislava Kocic ◽  
Gordana Tasic

Aim. To compare the sensitivity of detecting H. pylori in gastric biopsy and resection specimens using modified Giemsa stain and immunohistochemistry, using a commercially available anti-H. pylori antibody (Dako, Denmark). Methods. Gastric antral biopsy specimens showing chronic gastritis (28 cases) together with tissue blocks from gastrectomy specimens for duodenal ulcer (2 cases) were stained with modified Giemsa and immunoenzymatic alkaline phosphatase - anti-alkaline phosphatase (APAAP) method, and were carefully examined for the presence of H. pylori. Results. Using a modified Giemsa stain, the spiral shaped bacteria of H. pylori stained blue, were attached to the brush border of the gastric foveolar epithelial cells. However, the specificity of modified Giemsa stain depended on the morphological appearance of H. pylori. The specificity of immunostaining permitted detection of low numbers or even single organisms. In all cases bacteria were more prominent and easier to detect in immunostained preparations. H. pylori was identified in 22 (73.3%) of 30 sections stained with modified Giemsa stain, but it could be identified with greater frequency in sections stained with APAAP, in 27 (90%) of 30 sections. Conclusion. Immunohistochemical identification of H. pylori was better than Giemsa stain for detecting that organism.


2012 ◽  
Vol 64 (4) ◽  
pp. 1297-1299
Author(s):  
Tatjana Babic ◽  
Biljana Miljkovic-Selimovic ◽  
Branislava Kocic ◽  
A. Nagorni ◽  
Ljiljana Ristic

The culture of Helicobacter pylori from a gastric biopsy is the ?gold standard? in the diagnosis of H. pylori infection. However, the primary isolation of H. pylori from gastric biopsies is rather demanding. The duration of incubation for the isolation of H. pylori has been recommended to be five to seven days: in the present case, we found that a prolonged incubation period allowed the successful isolation of H. pylori from a patient with ulcus ventriculi. Biopsies were placed directly into transport medium and processed for culture within two hours. On day 14, one suspected H. pylori-like colony appeared on one of the plates. The isolate was confirmed to be H. pylori based on its typical colony morphology, negative Gram stain, and positive urease, catalase and oxidase tests. The isolate, requiring 14 days recovery, later exhibited the normal growth characteristics of H. pylori strains, indicating its unusually long incubation requirement was a temporary predicament.


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