Unreliability of results of PCR detection of Helicobacter pylori in clinical or environmental samples. J Clin Microbiol. 2009;47:738-742. [PMID: 19129407 DOI: 10.1128/jcm.01563-08]

Standard addition method for rapid, cultivation-independent quantification of Legionella pneumophila cells by qPCR in biotrickling filters

Cultivation-independent molecular biological methods are essential to rapidly quantify pathogens like Legionella pneumophila (L. pneumophila) which is important to control aerosol-generating engineered water systems. A standard addition method was established to quantify L. pneumophila in the very complex matrix of process water and air of exhaust air purification systems in animal husbandry. Therefore, cryopreserved standards of viable L. pneumophila were spiked in air and water samples to calibrate the total bioanalytical process which includes cell lysis, DNA extraction, and qPCR. A standard addition algorithm was employed for qPCR to determine the initial concentration of L. pneumophila. In mineral water, the recovery rate of this approach (73%-134% within the concentration range of 100-5000 Legionella per mL) was in good agreement with numbers obtained from conventional genomic unit (GU) calibration with DNA standards. In air samples of biotrickling filters, in contrast, the conventional DNA standard approach resulted in a significant overestimation of up to 729%, whereas our standard addition gave a more realistic recovery of 131%. With this proof-of-principle study, we were able to show that the molecular biology-based standard addition approach is a suitable method to determine realistic concentrations of L. pneumophila in air and process water samples of biotrickling filter systems. Moreover, this quantification strategy is generally a promising method to quantify pathogens in challenging samples containing a complex microbiota and the classical GU approach used for qPCR leads to unreliable results.

The link between Helicobacter pylori infection and gallbladder and biliary tract diseases: A review

Helicobacter pylori is a gram-negative pathogen commonly associated with peptic ulcer disease and gastric cancer. H. pylori infection has also been reported in cholelithiasis, cholecystitis, gallbladder polyps, and biliary tract cancers. However, the association between H. pylori and gallbladder and biliary tract pathologies remains unclear due to the paucity of literature. In response to the current literature gap, we aim to review and provide an updated summary of the association between H. pylori with gallbladder and biliary tract diseases and its impact on their clinical management. Relevant peer-reviewed studies were retrieved from Medline, PubMed, Embase, and Cochrane databases. We found that H. pylori infection was associated with cholelithiasis, chronic cholecystitis, biliary tract cancer, primary sclerosing cholangitis, and primary biliary cholangitis but not with gallbladder polyps. While causal links have been reported, prospective longitudinal studies are required to conclude the association between H. pylori and gallbladder pathologies. Clinicians should be aware of the implications that H. pylori infection has on the management of these diseases.

Analysis of Genetic Relatedness between Gastric and Oral Helicobacter pylori in Patients with Early Gastric Cancer Using Multilocus Sequence Typing

The oral cavity is the second most colonized site of Helicobacter pylori after the stomach. This study aimed to compare the genetic relatedness between gastric and oral H. pylori in Japanese patients with early gastric cancer through multilocus sequence typing (MLST) analysis using eight housekeeping genes. Gastric biopsy specimens and oral samples were collected from 21 patients with a fecal antigen test positive for H. pylori. The number of H. pylori allelic profiles ranged from zero to eight since the yield of DNA was small even when the nested PCR was performed. MLST analysis revealed that only one patient had a matching oral and gastric H. pylori genotype, suggesting that different genotypes of H. pylori inhabit the oral cavity and gastric mucosa. The phylogenetic analysis showed that oral H. pylori in six patients was similar to gastric H. pylori, implying that the two strains are related but not of the same origin, and those strains may be infected on separate occasions. It is necessary to establish a culture method for oral H. pylori to elucidate whether the oral cavity acts as the source of gastric infection, as our analysis was based on a limited number of allele sequences.

Association of Chronic Periodontitis with Helicobacter pylori Infection in Stomach or Mouth: A Systematic Review and Meta-Analysis

Helicobacter pylori (H. pylori) infection and periodontitis are both inflammatory conditions associated with systemic diseases. Researchers have attempted to investigate the correlation between them. This systematic review and meta-analyses were conducted to investigate the association of H. pylori infection in the stomach and/or in subgingival plaque and gingival crevicular fluid with chronic periodontitis. The protocol was created according to the Preferred Reporting Items for Systematic review and Meta-Analysis Protocols (PRISMA-P) statement. The study was designed according to the Cochrane criteria. A comprehensive literature search was performed in MEDLINE, Scopus, and CENTRAL, combined with hand-searching and assessment of gray literature. The meta-analysis of the included studies was made by the Review Manager (RevMan) 5.4 software. The effect measure of the outcome was odds ratios with 95% confidence intervals. Heterogeneity was assessed by chi-square and I2. Four observational studies involving 818 subjects were included in this meta-analysis. The odds of oral H. pylori presence were higher in patients with chronic periodontitis, compared to healthy controls, with an odds ratio of 1.87 (95% confidence interval 0.85–4.10; p = 0.12). The odds of the presence of H. pylori in the stomach also were higher in patients with chronic periodontitis, with an odds ratio of 1.80 (95% confidence interval 0.82–3.95; p = 0.15). There is no evidence for an association between chronic periodontitis and the prevalence of H. pylori, detected either in subgingival plaque and gingival crevicular fluid or in the stomach.

Helicobacter pylori Infection, Its Laboratory Diagnosis, and Antimicrobial Resistance: a Perspective of Clinical Relevance

Despite the recent decrease in overall prevalence of Helicobacter pylori infection, morbidity and mortality rates associated with gastric cancer remain high. The antimicrobial resistance developments and treatment failure are fueling the global burden of H. pylori-associated gastric complications. Accurate diagnosis remains the opening move for treatment and eradication of infections caused by microorganisms. Although several reports have been published on diagnostic approaches for H. pylori infection, most lack the data regarding diagnosis from a clinical perspective. Therefore, we provide an intensive, comprehensive, and updated description of the currently available diagnostic methods that can help clinicians, infection diagnosis professionals, and H. pylori researchers working on infection epidemiology to broaden their understanding and to select appropriate diagnostic methods. We also emphasize appropriate diagnostic approaches based on clinical settings (either clinical diagnosis or mass screening), patient factors (either age or other predisposing factors), and clinical factors (either upper gastrointestinal bleeding or partial gastrectomy) and appropriate methods to be considered for evaluating eradication efficacy. Furthermore, to cope with the increasing trend of antimicrobial resistance, a better understanding of its emergence and current diagnostic approaches for resistance detection remain inevitable.

The validity evaluation of different 16srRNA gene primers for helicobacter detection urgently requesting to design new specific primers

Molecular diagnosis of helicobacters by PCR is simpler, more accurate, and feasible compared to other diagnostic methods. Validity and accuracy are highly dependent on the PCR primer design, diffusion time, and mutation rate of helicobacters. This study aimed to design 16srRNA -specific primers for Helicobacter spp. and H. pylori. Application of comparative statistical analysis of the diagnostic utility of the most available 16srRNA genus-specific primers. The new primers were designed using bioinformatics tools (MAFFT MSA and Gblocks command line). A comparative study was applied on nine genus-specific 16srRNA primers in comparison to the ConsH using in silico and laboratory evaluation. The results demonstrated that the best specificity and sensitivity of the primers designed for this study compared to other primers. The comparative study revealed that the heminested outer/inner primers were the worst. Although H276, 16srRNA(a), HeliS/Heli-nest, and Hcom had acceptable diagnostic utility, false positive and false negative results were obtained. Specificity testing on clinical samples indicated a surprising result; that H. pylori was not the sole enemy that we were looking for, but the Non-Helicobacter pylori Helicobacters should be considered as a real risk prognostic for gastric diseases, consequently, a specific diagnosis and treatment should be developed. This study concluded that our designed primers were the most specific and sensitive in comparison with other primers. In addition, in silico evaluation is not accurate enough for primer assessment and that the laboratory evaluation is mandatory.

Comparison of invasive histological and molecular methods in the diagnosis of Helicobacter pylori from gastric biopsies of Sudanese patients: a cross-sectional study

Background: The continuous rise in the number of patients suffering from Helicobacter pylori is probably due to the changes in modern life. Nowadays, patients suffering from gastrointestinal problems are diagnosed through invasive and non-invasive techniques. The choice of a diagnostic test is influenced by factors such as the tests' sensitivity and specificity, the clinical conditions, and the cost-effectiveness of the testing strategy. This study aimed to compare molecular detection methods of H. pylori by polymerase chain reaction (PCR) targeting the 16S rRNA, ureA and glmM genes with an invasive histopathological technique. Methods: 290 gastric biopsies were collected using gastrointestinal endoscopy from patients with gastritis symptoms in different hospitals in Khartoum state. Two gastric biopsies were collected from each patient for PCR and histopathology. Results: A total of 103 (35.5%) samples were positive by histopathological examination, 88 (30.3%) by 16S rRNA, 39 (13.4%) by glmM gene, and 56 (19.3%) by ureA gene. The highest sensitivity was observed in 16S rRNA (46.6%), followed by glmM (24.3%) and ureA (23.3%). While the best specificity was observed in glmM gene (92.5%), followed by ureA (82.3%) and 16S rRNA (78.6%). Conclusion: PCR test targeting the 16S rRNA gene exhibited the best results for molecular detection of H. pylori compared to other genes.

Comparison of invasive histological and molecular methods in the diagnosis of Helicobacter pylori from gastric biopsies of Sudanese patients: a cross-sectional study

Background: The continuous rise in the number of patients suffering from Helicobacter pylori is probably due to the changes in modern life. Nowadays, patients suffering from gastrointestinal problems are diagnosed through invasive and non-invasive techniques. The choice of a diagnostic test is influenced by factors such as the tests' sensitivity and specificity, the clinical conditions, and the cost-effectiveness of the testing strategy. This study aimed to compare molecular detection methods of H. pylori by polymerase chain reaction (PCR) targeting the 16S rRNA, ureA and glmM genes with an invasive histopathological technique. Methods: 290 gastric biopsies were collected using gastrointestinal endoscopy from patients with gastritis symptoms in different hospitals in Khartoum state. Two gastric biopsies were collected from each patient for PCR and histopathology. Results: A total of 103 (35.5%) samples were positive by histopathological examination, 88 (30.3%) by 16S rRNA, 39 (13.4%) by glmM gene, and 56 (19.3%) by ureA gene. The highest sensitivity was observed in 16S rRNA (46.6%), followed by glmM (24.3%) and ureA (23.3%). While the best specificity was observed in glmM gene (92.5%), followed by ureA (82.3%) and 16S rRNA (78.6%). Conclusion: PCR test targeting the 16S rRNA gene exhibited the best results for molecular detection of H. pylori compared to other genes.

Tumor tissue Helicobacter pylori and human papillomavirus infection in head and neck squamous cell carcinoma patients and association with clinicopathological indices: A cross-sectional medical survey

Background:

The associations between Helicobacter pylori and human papillomavirus (HPV) with head and neck squamous cell carcinomas (HNSCCs) are approved before. However, the association between demographic, clinicopathological, and histologic characteristics of HNSCC patients and molecular detection of HPV and H. pylori has not been enough investigated.

Materials and Methods:

In this cross-sectional study, 62 patients with HNSCC from January 2016 to February 2020 were entered the study. For H. pylori detection 16S ribosomal RNA and glmM genes and HPV detection, MY09 and MY11 genes were used. P < 0.05 is considered as significant level.

Results:

There were 34 patients with advanced-stage cancer (54.8%). Grade I patients (61.3%) had the highest frequency. There were 20 (32.25%) and 7 (11.29%) patients with positive H. pylori infection among tumor tissue and healthy tissue margins, respectively. Positive HPV infections were in 8 (12.90%) and 3 (4.83%) patients, respectively, in tumor tissue and healthy tissue margins (P = 0.01). There was a significant difference between histological grade and infection to HPV among HNSCC patients (P = 0.01), and most of the positive HPV cases had well-, moderate-, and poorly-differentiated tumors, respectively. Our study showed a significant increase in HPV infection in the advanced-stage group compared to the early-stage group (P = 0.05).

Conclusion:

Our study findings concluded a significant relationship between HPV infection in HNSCC patients with age, stage, and grade. In summary, our findings based on polymerase chain reaction analysis concluded remarkably a potential role of HPV infection and to some extent H. pylori infection into the contribution of HNSCC malignancies.

DNA diagnostics for reliable and universal identification of Helicobacter pylori

Reliable diagnostics are a major challenge for the detection and treatment of Helicobacter pylori (H. pylori) infection. Currently at the forefront are non-invasive urea breath test (UBT) and stool antigen test (SAT). Polymerase chain reaction (PCR) is not endorsed due to nonspecific primers and the threat of false-positives. The specificity of DNA amplification can be achieved by nested PCR (NPCR), which involves two rounds of PCR. If the primers are properly designed for the variable regions of the 16S rRNA gene, it is not difficult to develop an NPCR assay for the unambiguous identification of H. pylori. Elaborate NPCR for a 454 bp amplicon was validated on 81 clinical biopsy, stool, and saliva samples, each from the same individuals, and compared with available H. pylori assays, namely histology, rapid urease test, SAT, and ¹³C-UBT. The assay was much more sensitive than simple PCR, and it was equally sensitive in biopsy samples as the ¹³C-UBT test, which is considered the gold standard. In addition, it is sufficiently specific because sequencing of the PCR products exclusively confirmed the presence of H. pylori-specific DNA. However, due to the threshold and lower abundance, the sensitivity was much lower in amplifications from stool or saliva. Reliable detection in saliva also complicates the ability of H. pylori to survive in the oral cavity aside from and independent of the stomach. The reason for the lower sensitivity in stool is DNA degradation; therefore, a new NPCR assay was developed to obtain a shorter 148 bp 16S rRNA amplicon. The assay was validated on stool samples from 208 gastroenterological patients and compared to SAT results. Surprisingly, this NPCR revealed the presence of H. pylori in twice the number of samples as SAT, indicating that many patients are misdiagnosed, not treated by antibiotics, and their problems are interpreted as chronic. Thus, it is unclear how to properly diagnose H. pylori in practice. In the first approach, SAT or UBT is sufficient. If samples are negative, the 148 bp amplicon NPCR assay should be performed. If problems persist, patients should not be considered negative, but due to threshold H. pylori abundance, they should be periodically tested. The advantage of NPCR over UBT is that it can be used universally, including questionable samples taken from patients with achlorhydria, receiving proton pump inhibitors, antibiotics, bismuth compound, intestinal metaplasia, or gastric ulcer bleeding.

Helicobacter pylori genotypes associated with gastric cancer and dysplasia in Colombian patients

INTRODUCTION AND AIMS

Colombia has high incidence levels of gastric cancer that can be explained by the genetic variability of Helicobacter pylori (H. pylori). Our aim was to establish the relation of the H. pylori CagA and VacA genotypes to dysplasia and gastric cancer, in a high-risk population.

MATERIAL AND METHODS

A case-control study was conducted on 202 patients from a high-risk cancer zone. Patients with dysplasia and gastric cancer (cases) and patients with nonatrophic gastritis (controls) were included. Endoscopic sampling and histologic classification were carried out according to the Sydney system and the Lauren classification. Genetic information was obtained through polymerase chain reaction on paraffin blocks. The measures of association of the variables of interest were evaluated in bivariate and multivariate models. A P<0.05 was considered statistically significant and the SPSS version 25 program was employed.

RESULTS

Age above 50 years (OR: 23.76; CI: 8.40-67.17; P=0.000) and the VacA s1m1 genotype (OR: 6.18; CI: 1.25-30.51; P=0.025) were associated with higher risk for developing dysplasia and gastric cancer. The CagA+ genotype was not found to be a risk factor for developing those pathologies (OR: 1.02; CI: 0.39-2.62; P=0.965).

CONCLUSIONS

The H. pylori VacA genotypes are markers for the development of gastric cancer. That information could be used to create a risk index in a predictive model to optimize the healthcare of higher-risk patients.

Demographic, Chemical, and Helicobacter pylori Positivity Assessment in Different Types of Gallstones and the Bile in a Random Sample of Cholecystectomied Iranian Patients with Cholelithiasis

BACKGROUND

The occurrence of stones in the gallbladder or common bile duct and the symptoms and complications they cause is called gallstone disease. The symptoms of gallstone disease range from mild, nonspecific symptoms to a severe right quadrant abdominal pain. Characteristics of gallstone types in an Iranian population have not been well studied before and there are very limited studies on the demographic pattern of stone types in our country, so this study is one of the first studies on its kind on the epidemiology of gallstone types in Iran. As information on chemical components of the stone will help in the management and prevention of gallstones, in this study, we aimed to do chemical component analysis of gallstones including cholesterol, bilirubin, and calcium. Given the conflicting reports about the relationship between H. pylori infections and gallstone formation, this study aimed to investigate the relationship between H. pylori positivity in the bile specimen of Iranian patients with cholelithiasis and formation and type of stone.

METHODS

This prospective study reviewed a total of 196 patients who underwent cholecystectomy for symptomatic cholelithiasis at Shahid Beheshti Training and Research Hospital affiliated to the Yasuj University of Medical Sciences between September 2015 and May 2018. Chemical analysis of gallstone components performed using the colorimetry method. Microbiological analysis for H. pylori was done using the OnSite H. pylori Ag Rapid Test on the bile sample. For the validation test of bile, the H. pylori Rapid Stool Ag Test on stool was used, and Cohen's Kappa statistical analysis was done next.

RESULTS

There were significant associations between the stone types and age, chemical composition of the stones such as calcium, cholesterol, and bilirubin levels, and also H. pylori positivity and cholesterol and bilirubin levels; however, no significant association was found between the stone types and sex, H. pylori positivity and age, sex, stone types, and calcium level. The main bile and validity tests were matched to the substantial agreement according to Cohen's Kappa analysis. The most common drugs used were proton pump inhibitors, nonsteroidal anti-inflammatory drugs, antihypertensive drugs, and oral contraceptives.

CONCLUSIONS

This study suggested that the chemical composition of the stones could predict the presence of bacteria, there is no correlation between H. pylori and gallstone formation, and some of the drugs could be predisposing factors for gallstones. This work provides an objective basis for further research into gallbladder stone formation; meanwhile, it has great significance in the treatment and prevention of gallbladder stones. Trial registration. The project was found to be in accordance to the ethical principles and the national norms and standards for conducting research in Iran with the approval ID IR.YUMS.REC.1399.147 and date 2020.09.23, and this project is the result of a residency dissertation to obtain the specialty in general surgery, which has been registered with the research project number 960159 in the Vice Chancellor for Research and Technology Development of the Yasuj University of Medical Sciences, Yasuj, Iran, URL: https://ethics.research.ac.ir/EthicsProposalViewEn.php?id=160634.

Profile of Helicobacter pylori cagA &vacA genotypes and its association with the spectrum of gastroduodenal disease

PURPOSE

Globally, H. pylori virulence factors cagA and vacA genotypes and its variation is leading to the austere form of the gastroduodenal disease. Our objectives were to detect H. pylori in dyspeptic patients from biopsy samples with the validation of the various existing diagnostic tools and to screen the cagA, vacA genotypes profile from biopsy specimens and how it impacts in progression of gastroduodenal disease in southern India.

METHODS

374 patients who attended endoscopy unit at Kasturba Hospital, Manipal with their consent obtained their biopsies. H. pylori were detected by HPE, Culture, RUT and PCR and its virulence gene were patterned with PCR.

RESULTS

The positive rate of H. pylori by HPE, RUT, Culture and PCR were 51.33%, 47.1%, 32.4% and 50.3% respectively and comparison by Bayesian LCMs analysis showed PCR is superior among them. The frequency of H. pylori virulence gene viz cagPAI (cagA) were 80.9%, and vacA alleles-s1m1 (42%), s1m2 (33%) and s2m2 (25%) genotypes by PCR respectively. Four combinations of cagA/vacA genotypes were noted, majority of strains harboured cagA⁺/vacA s1m1 genotypes (42.6%), interestingly this hyper-virulent strain more frequently seen in severe gastroduodenal disease whereas cagPAI negative strains as well as cagA^-/vacA s2m2 combinations (19.1%) are seen most commonly in functional dyspepsia cases and depicted significant association by Chi-square test.

CONCLUSIONS

This study validates and compares the existing diagnostic methods for detecting H. pylori in biopsies. Also, it reveals some pattern of virulence gene combination will play a vital role in disease progression.

Helicobacter pylori genotypes associated with gastric cancer and dysplasia in Colombian patients

INTRODUCTION AND AIMS

Colombia has high incidence levels of gastric cancer that can be explained by the genetic variability of Helicobacter pylori (H. pylori). Our aim was to establish the relation of the H. pylori CagA and VacA genotypes to dysplasia and gastric cancer, in a high-risk population.

MATERIAL AND METHODS

A case-control study was conducted on 202 patients from a high-risk cancer zone. Patients with dysplasia and gastric cancer (cases) and patients with nonatrophic gastritis (controls) were included. Endoscopic sampling and histologic classification were carried out according to the Sydney system and the Lauren classification. Genetic information was obtained through polymerase chain reaction on paraffin blocks. The measures of association of the variables of interest were evaluated in bivariate and multivariate models. A P<0.05 was considered statistically significant and the SPSS version 25 program was employed.

RESULTS

Age above 50 years (OR: 23.76; CI: 8.40-67.17; P=0.000) and the VacA s1m1 genotype (OR: 6.18; CI: 1.25-30.51; P=0.025) were associated with higher risk for developing dysplasia and gastric cancer. The CagA+ genotype was not found to be a risk factor for developing those pathologies (OR: 1.02; CI: 0.39-2.62; P=0.965).

CONCLUSIONS

The H. pylori VacA genotypes are markers for the development of gastric cancer. That information could be used to create a risk index in a predictive model to optimize the healthcare of higher-risk patients.

Current Prevalence of Oral Helicobacter pylori among Japanese Adults Determined Using a Nested Polymerase Chain Reaction Assay

In Japan, gastric Helicobacter pylori infection prevalence has markedly decreased with socioeconomic development. We aimed to investigate the prevalence of oral H. pylori in Japanese adults in 2020 by sex, age, sampling site, and medical history. Unstimulated saliva, supragingival biofilm, and tongue coating were obtained from 88 subjects-with no complaints of upper digestive symptoms-attending a dentist's office for dental check-up or disorders. Supragingival biofilm was collected from the upper incisors, lower incisors, upper right molars and lower left molars to analyze the characteristic distribution. Oral H. pylori was detected using nested polymerase chain reaction. Oral H. pylori prevalence did not statistically differ by sex or age. Supragingival biofilm (30.7%) was the most common oral H. pylori niche; it was also detected in 4.5% of saliva and 2.3% of tongue samples. The lower incisor was the most common site among the supragingival biofilm samples, followed by the upper incisors, lower left molars, and upper right molars. Oral H. pylori DNA was frequently detected in patients with a history of gastric H. pylori infection. Oral H. pylori has a characteristic distribution independent of sex and age, suggesting that it is part of the normal microflora in the adult oral cavity.

Diagnostic reliability of nested PCR depends on the primer design and threshold abundance of Helicobacter pylori in biopsy, stool, and saliva samples

BACKGROUND

The aim of this work was to find a reliable nested PCR for the detection of Helicobacter pylori in biopsy, stool, and saliva specimens.

MATERIALS AND METHODS

Novel nested PCR was elaborated and validated on 81 clinical biopsy, stool, and saliva samples from the same individual and compared to available H pylori assays: histology, rapid urease test (RUT), stool antigen test (SAT), ¹³ C-urea breath test (UBT).

RESULTS

The efficiency and selectivity of 17 published nested polymerase chain reactions (PCR) available for Helicobacter pylori detection were re-evaluated. Most of them had serious limitations and mistakes in primer design. Hence, we elaborated a nested PCR for the unambiguous identification of H pylori in biopsy, stool, and saliva, using primers targeted to variable regions of the 16S ribosomal RNA (rRNA) gene. Moreover, we determined the detection limit by adding a known number of cells. This number was as low as 0.5 cells in a PCR vial, but due to the DNA isolation procedures, it required 1-5 × 10³ cells/g or ml of specimen. The sensitivity for nested PCR from stomach biopsies was on the same scale as ¹³ C-UBT (93.8%), but it was much lower in amplifications from stool (31.3%). Sequencing of all obtained PCR products exclusively confirmed H pylori-specific DNA sequences.

CONCLUSIONS

Elaborated nested PCR assay can serve as an auxiliary method for controversial samples (patients with bleeding or taking proton-pump inhibitor) in laboratories with basic equipment. The sensitivity and specificity for the amplification from gastric biopsies was almost like ¹³ C-UBT. Despite the good sensitivity, the threshold occurrence and the ability to survive in the oral cavity aside from and independent of the stomach is the reason why H pylori DNA cannot be reliably detected in saliva, stool, and some biopsy samples.

Analysis of by high-throughput sequencing: Helicobacter pylori infection and salivary microbiome

Background

There have been reports of Helicobacter pylori (H. pylori) in the oral cavity and it has been suggested that the oral cavity may be a reservoir for H. pylori reflux from the stomach. High-throughput sequencing was used to assess the structure and composition of oral microbiota communities in individuals with or without confirmed H. pylori infection.

Methods

Saliva samples were obtained from 34 H. pylori infected and 24 H. pylori uninfected subjects. Bacterial genomic DNA was extracted and examined by sequencing by amplification of the 16S rDNA V3-V4 hypervariable regions followed by bioinformatics analysis. Saliva sampling was repeated from 22 of the 34 H. pylori infected subjects 2 months after H. pylori eradication.

Results

High-quality sequences (2,812,659) clustered into 95,812 operational taxonomic units (OTUs; 97% identity). H. pylori was detected in the oral cavity in infected (12/34), uninfected (11/24) and eradicated (15/22) subjects by technique of high-throughput sequencing, occupying 0.0139% of the total sequences. Alpha diversity of H. pylori infected subjects was similar to that of uninfected subjects (Shannon: 1417.58 vs. 1393.60, p > 0.05, ACE: 1491.22 vs. 1465.97, p > 0.05, Chao 1: 1417.58 vs. 1393.60, p > 0.05, t-test). Eradication treatment decreased salivary bacterial diversity (Shannon, p = 0.015, ACE, p = 0.003, Chao 1, p = 0.002, t-test). Beta diversity analysis based on unweighted UniFrac distances showed that the salivary microbial community structure differed between H. pylori infected and uninfected subjects (PERMANOVAR, pseudo-F: 1.49, p = 0.033), as well as before and after H. pylori eradication (PERMANOVAR, pseudo-F: 3.34, p = 0.001). Using LEfSe analysis, 16 differentially abundant genera were defined between infected and uninfected subjects, 12 of which had a further alteration after successful eradication.

Conclusions

Our study using high-throughput sequencing showed that H. pylori was present commonly in the oral cavity with no clear relation to H. pylori infection of the stomach. Both H. pylori infection and eradication therapy caused alterations in community and structure of the oral microbiota.

Trial registration

clinicaltrials.gov, NCT03730766. Registered 2 Nov 2018 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/ NCT03730766.

Helicobacter pylori severely reduces expression of DNA repair proteins PMS2 and ERCC1 in gastritis and gastric cancer

Gastric cancers are the third leading cause of cancer mortality in the world. Helicobacter pylori causes over 60 % of all stomach cancers. Colonization of the gastric mucosa by H. pylori results in increased DNA damage. Repair of DNA damage may also be reduced by H. pylori infection. Reduced DNA repair in combination with increased DNA damage can cause carcinogenic mutations. During progression to gastric cancer, gastric epithelium goes through stages of increasing pathology. Determining the levels of DNA repair enzymes during progression to gastric cancer could illuminate treatment approaches. Our aim is to determine the level of gastric expression of DNA repair proteins ERCC1 (a nucleotide excision repair enzyme) and PMS2 (a mismatch repair enzyme) in the presence of H. pylori infection at successive stages of gastric pathology and in gastric cancers. We analyzed gastric tissues of 300 individuals, including 30 without dyspepsia, 200 with dyspepsia and 70 with gastric cancers. The presence of H. pylori, gastric pathology and expression of DNA repair proteins ERCC1 and PMS2 were evaluated. Infection by H. pylori carrying the common cagA gene reduced median nuclear expression of ERCC1 and PMS2 to less than 20 % and 15 % of normal, respectively, in all pathologic stages preceding cancer. ERCC1 and PMS2 nuclear expression was 0-5 % of normal in gastric cancers. H. pylori can cause deficiency of ERCC1 and PMS2 protein expression. These deficiencies are associated with gastric pathology and cancer. This reduction in DNA repair likely causes carcinogenic mutations. Substantially reduced ERCC1 and PMS2 expression appears to be an early step in progression to H. pylori-induced gastric cancer.

Association between Helicobacter pylori infection and dental pulp reservoirs in Japanese adults

Background

Helicobacter pylori (H. pylori) colonize the stomach and are considered an etiological agent of gastric cancer. The oral cavity is a transmission route to the stomach, but the exact site of colonization has not yet been explicated. Our study investigated the association between H. pylori infection and presence in oral samples.

Methods

Dental pulp, supragingival plaque, and saliva from 192 patients visiting the Dentistry’s outpatient clinic were collected for testing. The H. pylori ureA gene was identified via Nested PCR. Urine anti-H. pylori antibody test was utilized to detect infection.

Results

Twenty-five subjects were found to be antibody-positive. PCR analysis of dental pulp revealed that 23 subjects possessed the ureA gene. Twenty-one subjects were positive for both antibodies and genes in dental pulp. PCR testing revealed that 2 subjects were positive in dental plaque but negative for saliva. The subjects positive for H. pylori in dental pulp expressed clinical signs of severe dental caries.

Conclusions

H. pylori infected subjects expressed H. pylori in samples from the oral cavity. The main reservoir for infection within the oral cavity was determined to be dental pulp. Moreover, H. pylori are likely transmitted from dental caries to the root canal.

Potential transmission sources of Helicobacter pylori infection: detection of H. pylori in various environmental samples

PURPOSE

Helicobacter pylori is one of the most common human infectious agents which may be transmitted via water. This study was designed to test H. pylori presence via molecular methods in various aquatic environments as well as sewage sludge (SS) to understand the role of these environments in the pathogen's transmission.

METHODS

specific primers for the 16S rRNA and ureA genes of H. pylori were used in a nested and semi-nested PCR, respectively. Detection sensitivity of H. pylori in environmental samples by semi-nested PCR was also compared with real-time PCR. Analysis of fecal coliforms (FC) as pollution indicator bacteria was also performed.

RESULTS

H. pylori 16S rRNA gene was detected in 36% (14/39) of wastewater samples and 8% (2/25) of water samples, while amplification of ureA gene yielded only two positive results. None of the SS samples were positive for H. pylori and real-time PCR could not identify H. pylori in any of the samples. The results showed no correlation between the presence of H. pylori and FC.

CONCLUSIONS

Our result revealed the widespread presence of H. pylori in wastewater samples which indicates wastewater may be a source for dissemination and transmission of H. pylori infection. Further research is needed to determine the risk of H. pylori in wastewater reuse for irrigation of crops.

Application of PCR and Microscopy to Detect Helicobacter pylori in Gastric Biopsy Specimen among Acid Peptic Disorders at Tertiary Care Centre in Eastern Nepal

BACKGROUND

Helicobacter pylori infection is most prevalent in developing countries. It is an etiological agent of peptic ulcer, gastric adenocarcinoma, and mucosal-associated lymphoid tissue (MALT) lymphoma. Despite the development of different assays to confirm H. pylori infection, the diagnosis of infection is challenged by precision of the applied assay. Hence, the aim of this study was to understand the diagnostic accuracy of PCR and microscopy to detect the H. pylori in the gastric antrum biopsy specimen from gastric disorder patients.

METHODS

A total of 52 patients with gastric disorders underwent upper gastrointestinal endoscopy with biopsy. The H. pylori infection in gastric biopsies was identified after examination by microscopy and 23S rRNA specific PCR. The agreement between two test results were analysed by McNemar's test and Kappa coefficient.

RESULT

H. pylori infection was confirmed in 9 (17.30%) patients by both assays, 6.25% in antral gastritis, 22.22% in gastric ulcer, 100% in gastric ulcer with duodenitis, 50% in gastric ulcer with duodenal ulcer, and 33.33% in severe erosive duodenitis with antral gastritis. Out of nine H. pylori infection confirmed patients, 3 patients were confirmed by microscopy and 8 patients by PCR. In case of two patients, both microscopy and PCR assay confirmed the H. pylori infection. The agreement between two test results was 86.54% and disagreed by 13.46% (p value > 0.05).

CONCLUSION

We found that PCR assay to detect H. pylori is more sensitive than microscopy. However, we advocate for the combination of both assays to increase the strength of diagnostic accuracy due to the absence of the gold standard assay for H. pylori infection.

The urban and rural capybaras (Hydrochoerus hydrochaeris) as reservoir of Salmonella in the western Amazon, Brazil

ABSTRACT: The capybara (Hydrochoerus hydrochaeris) is the largest rodent in the world. In the state of Acre, Brazil, populations of capybaras have been increasing significantly. The role of capybaras in the transmission of certain bacterial zoonotic infections is not well understood, including bacteria of the genus Salmonella. Salmonella spp. generally cause enteritis or septicemia in mammals, however many mammalian species can carry the bacteria asymptomatically and shed it in their feces. To better understand the possible role of capybaras as reservoirs of Salmonella spp., we conducted a study of Salmonella within fecal samples from capybara in Acre. In a convenience sample, 54 capybaras from two urban and two rural areas of Acre were captured and kept for three to four days for sampling. None of the animals were symptomatic of any intestinal illness. Three separate fecal samples were collected from each animal, during their stays in captivity. Each sample was cultured for the presence of Salmonella spp. at the bacteriology laboratory of the Veterinary College of the Federal University of Acre. Samples were seeded in tetrationate pre-enrichment broth and in pre-enrichment broth peptone. After a 24 hour of incubation all samples were streaked on MacConkey Agar (MC) and Salmonella-Shigella Agar (SS). Suggestive colonies were submitted to biochemical analysis. Salmonella compatible colonies according to biochemical profile were submitted to serotyping (Sorokit for Salmonella - Probac do Brasil). In addition, the first sample from each of the 54 capybara was tested for Salmonella spp. using PCR targeting gene hilA. Eight (5%) of the 162 samples examined by bacterial culture were positive for Salmonella spp., while four (7%) of the 54 examined by PCR were positive. From the eight positive animals on culture, five were from urban area and three from rural area. On PCR, only one positive animal was from urban area and four were from rural area. Overall, by either test, one of the 54 animals was positive. All samples were collected in free - living animals with no apparent clinical signs of salmonellosis, indicating the potential of capybara as reservoir on this ecosystem.

Molecular and clinical analyses of Helicobacter pylori colonization in inflamed dental pulp

Background

Recently, dental pulp has been considered a possible source of infection of Helicobacter pylori (H. pylori) in children. We previously developed a novel PCR system for H. pylori detection with high specificity and sensitivity using primer sets constructed based on the complete genome information for 48 H. pylori strains. This PCR system showed high sensitivity with a detection limit of 1–10 cells when serial dilutions of H. pylori genomic DNA were used as templates. However, the detection limit was lower (10²–10³ cells) when H. pylori bacterial DNA was detected from inflamed pulp specimens. Thus, we further refined the system using a nested PCR method, which was much more sensitive than the previous single PCR method. In addition, we examined the distribution and virulence of H. pylori in inflamed pulp tissue.

Methods

Nested PCR system was constructed using primer sets designed from the complete genome information of 48 H. pylori strains. The detection limit of the nested PCR system was 1–10 cells using both H. pylori genomic DNA and bacterial DNA isolated from inflamed pulp specimens. Next, distribution of H. pylori was examined using 131 inflamed pulp specimens with the nested PCR system. In addition, association between the detection of H. pylori and clinical information regarding endodontic-infected teeth were investigated. Furthermore, adhesion property of H. pylori strains to human dental fibroblast cells was examined.

Results

H. pylori was present in 38.9% of inflamed pulp specimens using the nested PCR system. H. pylori was shown to be predominantly detected in primary teeth rather than permanent teeth. In addition, samplings of the inflamed pulp were performed twice from the same teeth at 1- or 2-week intervals, which revealed that H. pylori was detected in most specimens in both samplings. Furthermore, H. pylori strains showed adhesion property to human dental fibroblast cells.

Conclusion

Our results suggest that H. pylori colonizes inflamed pulp in approximately 40% of all cases through adhesion to human dental fibroblast cells.

Primary antibiotic resistance and its relationship with cagA and vacA genes in Helicobacter pylori isolates from Algerian patients

The epidemiology of Helicobacter pylori resistance to antibiotics is poorly documented in Africa and especially in Algeria. The aim of our study was to determine the antibiotic resistance rates, as well as its possible relationship with VacA and CagA virulence markers of isolates from Algerian patients. One hundred and fifty one H. pylori isolate were obtained between 2012 and 2015 from 200 patients with upper abdominal pain. Antimicrobial susceptibility testing was performed for amoxicillin, clarithromycin, metronidazole, ciprofloxacin, rifampicin and tetracycline. Molecular identification of H. pylori and the detection of vacA and cagA genes were performed using specific primers. We found that H. pylori was present in 83.5% of collected biopsies, 54.9% of the samples were cagA positive, 49.67% were vacA s1m1, 18.30% were vacA s1m2 and 25.49% were vacA s2m2. Isolates were characterized by no resistance to amoxicillin (0%), tetracycline (0%), rifampicin (0%), a high rate of resistance to metronidazole (61.1%) and a lower rate of resistance to clarithromycin (22.8%) and ciprofloxacin (16.8%). No statically significant relationship was found between vagA and cagA genotypes and antibiotic resistance results (p > 0.5) except for the metronidazole, which had relation with the presence of cagA genotype (p = 0.001).

Sensitivity of Helicobacter pylori detection by Giemsa staining is poor in comparison with immunohistochemistry and fluorescent in situ hybridization and strongly depends on inflammatory activity

BACKGROUND

Conventional stainings (including H&E and special stains like Giemsa) are the most widely applied histopathologic detection methods of Helicobacter pylori (HP).

MATERIALS AND METHODS

We aimed to compare the diagnostic performance of Giemsa staining with immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) on a monocentric cohort of 2896 gastric biopsies and relate results to histologic alterations in order to find such histopathologic subgroups in which these methods underperform. All cases were categorized regarding presence or absence of chronic gastritis, inflammatory activity, and mucosal structural alterations.

RESULTS

Giemsa revealed 687 cases (23.7%), IHC 795 cases (27.5%), and FISH 788 cases (27.2%) as being HP positive. Giemsa showed significantly lower overall sensitivity (83.3%) compared to IHC (98.8%) and FISH (98.0%). Moreover, the sensitivity of Giemsa dramatically dropped to 33.6% in the nonactive cases. We found that sensitivity of Giemsa strongly depends on HP density and, accordingly, on the presence of activity. Structural alterations (intestinal metaplasia, atrophy, etc.) had only no or weak effect on sensitivity of the three stainings. Both IHC and FISH proved to be equally reliable HP detecting techniques whose diagnostic performance is minimally influenced by mucosal inflammatory and structural alterations contrary to conventional stainings.

CONCLUSIONS

We highly recommend immunohistochemistry for clinically susceptible, nonactive chronic gastritis cases, if the conventional stain-based HP detection is negative. Moreover, we recommend to use IHC more widely as basic HP stain. Helicobacter pylori FISH technique is primarily recommended to determine bacterial clarithromycin resistance. Furthermore, it is another accurate diagnostic tool for HP.

Helicobacter pylori DNA isolation in the stool: an essential pre-requisite for bacterial noninvasive molecular analysis

PURPOSE

Real-time polymerase chain reaction (RT-PCR) is a widely used technique for bacterial and viral infection diagnosis. Herein, we report our preliminary experience in retrieving H. pylori genetic sequences in stools and analyzing genotypic clarithromycin resistance by RT-PCR (noninvasive), with the aim of comparing this procedure with that performed on biopsy samples (invasive).

MATERIALS AND METHODS

After 'in vitro' demonstration of H. pylori DNA detection from pure and stool-mixed bacteria, 52 consecutive patients at the first diagnosis of infection were investigated. DNA was extracted from biopsy tissue and stool samples (THD^® Fecal Test, Italy). RT-PCR was performed to detect 23S rRNA encoding bacterial subunit gene and search A2143G, A2142C, A2142G point mutations for clarithromycin resistance assessment.

RESULTS

RT-PCR showed H. pylori positive DNA in all infected patients with full concordance between tissue and stool detection (100%). We found A2143G mutation in 10 (19.2%), A2142G in 4 (7.7%) and A2142C in 5 (9.6%) patients; there was a full agreement between biopsy and fecal samples. A2143G was found in all the four A2142G positive cases and in three out of the five A2142C positive strains. Overall clarithromycin resistance rate in our series was 23%.

CONCLUSIONS

Despite the need of confirmation on large sample, stool RT-PCR analysis could represent a feasible tool to detect H. pylori DNA sequences and antibiotic resistance point mutations. As compared to tissue molecular analysis, this technique is noninvasive, with potential advantages such as improvement of patient compliance, reduction of diagnostic procedure time/cost and improvement of therapeutic outcome.

An In Silico Approach for Identification of the Pathogenic Species, Helicobacter pylori and Its Relatives

Helicobacter is an economically important genus within the phylum Proteobacteria and include many species which cause many diseases in humans. With the conventional methods, it is difficult to identify them easily due to the high genetic similarity among its species. In the present study, 361 16S rRNA (rrs) gene sequences belonging to 45 species of genus Helicobacter were analyzed. Out of these, 264 sequences of 10 clinically relevant species (including Helicobacter pylori) were used. rrs gene sequences were analyzed to obtain a phylogenetic framework tree, in silico restriction enzyme analysis and species-specific conserved motifs. Protein sequences of another housekeeping gene, hsp60 were also subjected to phylogenetic analysis to supplement the data obtained using rrs sequences. Using these approaches, six out of ten species (including H. pylori) were easily segregated, whereas four species namely H. bilis, H. cinaedi, H. felis and Candidatus H. heilmannii were found to be heterogeneous. The above approaches have also helped in segregating unclassified sequences, thus proving them as an easy diagnostic method for identifying members of genus Helicobacter up to species level.

Establishment of a nested-ASP-PCR method to determine the clarithromycin resistance of Helicobacter pylori

AIM: To investigate clarithromycin resistance positions 2142, 2143 and 2144 of the 23SrRNA gene in Helicobacter pylori (H. pylori) by nested-allele specific primer-polymerase chain reaction (nested-ASP-PCR).

METHODS: The gastric tissue and saliva samples from 99 patients with positive results of the rapid urease test (RUT) were collected. The nested-ASP-PCR method was carried out with the external primers and inner allele-specific primers corresponding to the reference strain and clinical strains. Thirty gastric tissue and saliva samples were tested to determine the sensitivity of nested-ASP-PCR and ASP-PCR methods. Then, clarithromycin resistance was detected for 99 clinical samples by using different methods, including nested-ASP-PCR, bacterial culture and disk diffusion.

RESULTS: The nested-ASP-PCR method was successfully established to test the resistance mutation points 2142, 2143 and 2144 of the 23SrRNA gene of H. pylori. Among 30 samples of gastric tissue and saliva, the H. pylori detection rate of nested-ASP-PCR was 90% and 83.33%, while the detection rate of ASP-PCR was just 63% and 56.67%. Especially in the saliva samples, nested-ASP-PCR showed much higher sensitivity in H. pylori detection and resistance mutation rates than ASP-PCR. In the 99 RUT-positive gastric tissue and saliva samples, the H. pylori-positive detection rate by nested-ASP-PCR was 87 (87.88%) and 67 (67.68%), in which there were 30 wild-type and 57 mutated strains in gastric tissue and 22 wild-type and 45 mutated strains in saliva. Genotype analysis showed that three-points mixed mutations were quite common, but different resistant strains were present in gastric mucosa and saliva. Compared to the high sensitivity shown by nested-ASP-PCR, the positive detection of bacterial culture with gastric tissue samples was 50 cases, in which only 26 drug-resistant strains were found through analyzing minimum inhibitory zone of clarithromycin.

CONCLUSION: The nested-ASP-PCR assay showed higher detection sensitivity than ASP-PCR and drug sensitivity testing, which could be performed to evaluate clarithromycin resistance of H. pylori.

Comparative Evaluation of RUT, PCR and ELISA Tests for Detection of Infection with Cytotoxigenic H. pylori

PURPOSE

Helicobacter pylori is one of the most prevalent infectious agents in the world which causes a variety of gastrointestinal diseases including gastritis, peptic ulcer and gastric carcinoma. The objective of this study was to comparatively evaluate invasive (rapid urease test and polymerase chain reaction) and non-invasive (enzyme-linked immunosorbent assay) tests in diagnosis of infection with cytotoxigenic H. pylori.

METHODS

Biopsy specimens and sera were collected from 105 patients with gastric disorders. The presence of H. pylori infection in gastric biopsies was evaluated by RUT and PCR methods using chemotaxis signal transduction protein gene (CSTP), Urea C and HP-16srRNA primers. Serum samples were used for the ELISA test. Detection of infection with cag A-positive strains was performed by PCR and cag A-IgG ELISA kit.

RESULTS

Patients with at least two out of three positive results were regarded as infected. The sensitivity, specificity, predictive value and accuracy of the three different methods were evaluated. Of the 105 gastric biopsies, H. pylori were positive in 51 patients (48.57%). The best sensitivity (92.16%) belonged to RUT. The sensitivities of other tests including PCR and ELISA test were 88.24% and 90.20%, respectively. PCR showed the best specificity (94.44%), and the specificities of the other tests including RUT and ELISA test, were 90.74 % and 61.11%, respectively. Furthermore, results of PCR and cag A-IgG ELISA showed high prevalence of cag A-positive strain in the study population.

CONCLUSION

Based on our findings, serum ELISA is a rapid noninvasive test for screening of H. pylori infection in the absence of endoscopy indication. In addition, considering the high prevalence of cytotoxigenic H. pylori strains, cag A is suggested as a promising target for PCR and non- invasive ELISA tests for detection of infection with toxigenic strains.

Novel detection of Helicobacter pylori in fish: A possible public health concern

Helicobacter pylori is one of the most common human pathogens worldwide with serious clinical outcomes. Although, H. pylori is a major water-borne pathogen, its occurrence in fish is still unknown. This leads us to conduct the current study in order to clarify this point and to investigate the potential role of fish in the epidemiology of H. pylori. For this purpose, fecal samples were obtained from 315 fish from different species and were caught from various aquatic environments at different localities in Egypt. The obtained fecal samples were examined for the occurrence of H. pylori using monoclonal antibody based lateral flow immunoassay for antigen detection and after then the positive samples were confirmed by PCR. In addition, fecal samples from 18 fish handlers were also examined for the presence of H. pylori by lateral flow technique. The overall prevalence rates of H. pylori in the examined fish were 6.7% and 1.9% for LF and PCR, respectively, whereas 61.1% of fish handlers were positive. Only tilapia fish showed positive results by both techniques in rates 10.9% and 3.1%, respectively. Interestingly, H. pylori was detected in cultured and wild tilapia in various aquatic environments at different localities, whereas all other fish species were negative even those that were collected from the same water source where positive tilapia were caught. These results concluded that tilapia fish may be considered as a potential zoonotic reservoir for H. pylori and thus, H. pylori may become a new fish-borne pathogen. Further studies are needed to investigate the occurrence of H. pylori in other fish species.

Diagnosis of Helicobacter pylori Infection in the Proton Pump Inhibitor Era

Proton pump inhibitors (PPI) are a major cause of false-negative Helicobacter pylori test results. Detecting PPI use and stopping it 2 weeks before testing is the preferred approach to improve the reliability of H pylori diagnostic tests. Immunoblot and molecular methods may be useful for the detection of H pylori infection in difficult cases. When conventional tests are negative and eradication is strongly indicated, empirical H pylori treatment should be considered. In this article, an updated critical review of the usefulness of the various invasive and noninvasive tests in the context of extensive PPI use is provided.

Influence of prostate stem cell antigen gene polymorphisms on susceptibility to Helicobacter pylori-associated diseases: a case-control study

BACKGROUND

Patients with duodenal ulcer have a reduced risk of developing gastric cancer compared to those without. Recently, the prostate stem cell antigen (PSCA) rs2294008 C>T polymorphism was found to be associated with different pathogenesis of duodenal ulcer and gastric cancer developments. However, whether PSCA rs2294008 C>T polymorphism is associated with severity of gastric mucosal atrophy is unclear. We examined the influence of the PSCA rs2294008 C>T polymorphism on susceptibility to H. pylori-related diseases and the relationships between PSCA polymorphism and gastric mucosal atrophy.

METHODS

PSCA rs2294008 C>T polymorphism was assessed in H. pylori-positive Japanese patients (n = 488) with noncardia gastric cancer (n = 193), gastric ulcer (n = 84), duodenal ulcer (n = 61), and atrophic gastritis (n = 150), as well as in H. pylori-negatives (n = 266).

RESULTS

Frequency of PSCA rs2294008 C/C genotype in duodenal ulcer was 36.1%, which was significantly higher than those with gastric cancer (12.4%), gastric ulcer (19.0%), gastritis (10.7%), and H. pylori-negatives (19.5%) (p < .001). Compared with duodenal ulcer, having the T allele significantly increased the risk of gastric cancer (OR: 3.97, 95% CI: 2.02-7.80; p < .001), gastric ulcer (2.40, 1.13-5.10; p = .023), and gastritis (4.72, 2.26-9.86; p < .001). Mean pepsinogen (PG) I/PG II ratio in T allele carriers (2.17 ± 0.75) was significantly lower than that in C/C genotype (3.39 ± 1.27, p < .001).

CONCLUSIONS

The PSCA rs2294008 C>T polymorphism is associated with differing susceptibilities to H. pylori-associated diseases. The PSCA rs2294008 C>T polymorphism may be acting through induction of gastric mucosal atrophy, finally leading to development of gastric ulcer and gastric cancer in PSCA rs2294008 T allele carriers, but not duodenal ulcer.

An hypothesis: the dramatic decline in heart attacks in the United States is temporally related to the decline in duodenal ulcer disease and Helicobacter pylori infection

BACKGROUND

Studies of autopsies of military members dying in three US wars indicate that the prevalence of atherosclerosis in successive cohorts of healthy young men and women has dramatically decreased over the past half century.

OBJECTIVE

The objective of this study was to compare the decline in the prevalence of atherosclerosis and myocardial infarction with previously published studies on the decline in the prevalence of duodenal ulcer.

METHODS

A plot of the prevalence of coronary atherosclerosis and the prevalence of myocardial infarction in three cohorts of young men and women born from 1930 to 1980 was constructed.

RESULTS

The figure shows a marked decline in prevalence in atherosclerosis beginning in a military cohort born around 1930 and a similar marked decline in prevalence of myocardial infarction in the US population beginning in 1970. In published studies duodenal ulcer began to decline in prevalence in 1960. As duodenal ulcers began to occur at age 30 and myocardial infarctions began to occur at age 40 at the time of peak prevalence, the cohort born in 1930 was the first to experience a decline in prevalence of both duodenal ulcer and heart attacks.

CONCLUSION

The study shows that the decline in heart attacks is temporally related to the decline in duodenal ulcer and by inference, Helicobacter pylori infection.

Helicobacter pylori identification: a diagnostic/confirmatory method for evaluation

The Helicobacter pylori extra gastric reservoir is probably the oral cavity. In order to evaluate the presence of this bacterium in patients with periodontitis and suspicious microbial cultures, saliva was collected from these and non-periodontitis subjects. PCRs targeting 16S rRNA gene and a 860 bp specific region were performed, and digested with the restriction enzyme DdeI. We observed that the PCR-RFLP approach augments the accuracy from 26.2 % (16/61), found in the PCR-based results, to 42.6 % (26/61), which is an excellent indicator for the establishment of this low-cost procedure as a diagnostic/confirmatory method for H. pylori evaluation.

Detection of Helicobacter pylori in Oral Lesions

Background and aims. Helicobacter pylori is a microaerophilic gram-negative spiral organism. It is recognized as the etiologic factor for peptic ulcers, gastric adenocarcinoma and gastric lymphoma. Recently, it has been isolated from dental plaque and the dorsum of the tongue. This study was designed to assess the association between H. pylori and oral lesions such as ulcerative/inflammatory lesions, squamous cell carcinoma (SCC) and primary lymphoma.

Materials and methods. A total of 228 biopsies diagnosed as oral ulcerative/inflammatory lesions, oral squamous cell carcinoma (OSCC) and oral primary lymphoma were selected from the archives of the Pathology Department. Thirty-two samples that were diagnosed as being without any pathological changes were selected as the control group. All the paraffin blocks were cut for hematoxylin and eosin staining to confirm the diagnoses and then the samples were prepared for immunohistochemistry staining. Data were collected and analyzed.

Results. Chi-squared test showed significant differences between the frequency of H. pylori positivity in normal tissue and the lesions were examined (P=0.000). In addition, there was a statistically significant difference between the lesions examined (P=0.042). Chi-squared test showed significant differences between H. pylori positivity and different tissue types except inside the muscle layer as follows: in epithelium and in lamina propria (P=0.000), inside the blood vessels (P=0.003), inside the salivary gland duct (P=0.036), and muscle layer (P=0.122).

Conclusion. There might be a relation between the presence of H. pylori and oral lesions. Therefore, early detection and eradication of H. pylori in high-risk patients are suggested.

No detection of Helicobacter pylori in atherosclerotic plaques in end stage renal disease patients undergoing kidney transplantation

Chronic infection known to be a predisposing factor for the development of atherosclerosis. Several studies have found a possible role of Helicobacter pylori in the pathogenesis of atherosclerosis. The aim of this study was to investigate the presence of H. pylori in atherosclerotic plaques in iliac arteries in 25 end stage renal disease (ESRD) patients undergoing kidney transplantation. Esophagogastroduodenoscopy was performed in all patients before transplantation. Biopsy specimens obtained from gastric antrum were sent for pathologic evaluation. Gastric H. pylori infection was confirmed by microscopic assessment and rapid urease test. Arterial specimens were obtained from iliac arteries during kidney transplantation. Presence of H. pylori DNA in atherosclerotic plaques and healthy vessel samples was evaluated by the polymerase chain reaction (PCR). The mean age of patients was 44.1 ± 22.6 years. Risk factors in patients with atherosclerosis were hypertension (68%), diabetes mellitus (20%), hyperlipidemia (20%), positive family history (16%). Atherosclerotic plaques were found in 21 (84%) patients. PCR analysis did not detect H. pylori in any case. There was a significant relationship of atherosclerosis with hypertension (P = 0.006) but not with diabetes mellitus and hyperlipidemia (P = 0.5). There was no significant relationship between atherosclerosis and gastric H. pylori infection (P = 0.6). This study revealed no association between the presence of H. pylori as a pathogen of vessel walls and atherosclerosis in ESRD.

Determination of Helicobacter pylori Virulence Genes in Gastric Biopsies by PCR

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.

PCR detection of Helicobacter pylori in clinical samples

Helicobacter pylori is an important pathogen whose primary niche is the human stomach. H. pylori is etiologically associated with gastric inflammation (gastritis), peptic ulcer disease, and gastric cancer. Both noninvasive (e.g., urea breath and stool antigen tests) and invasive (gastric biopsy for histology, culture, or PCR) tests are used for diagnosis. PCR detection of H. pylori has been reported using a variety of clinical samples including gastric biopsy, gastric juice, saliva, dental plaque, and stools as well as environmental samples. Whenever possibly, noninvasive tests are preferred over invasive tests. H. pylori are excreted in the stool. Culture from stool is variable whereas stool antigen testing is widely used. Stool consists of a complicated mixture of commensal bacteria and chemicals and often includes inhibitors of PCR. Nevertheless, simple extraction methods are available to efficiently extract DNA from human stools and nested-PCR targeting the 23S rRNA gene have proven to be highly sensitive for the detection of H. pylori. Detection of clarithromycin susceptibility/resistance is important clinically and the mutation of the 23S rRNA gene responsible for resistance can also be detected using stool. This described method can be modified for other clinical samples such as gastric juice or biopsy material.

Comparing Multiplex PCR and Rapid Urease Test in the Detection of H. pylori in Patients on Proton Pump Inhibitors

Background. This study was conducted to assess the diagnostic value of a multiplex PCR assay to detect H. pylori infection and to further evaluate the negative results from the CLOtest on patients with and without PPI treatment. Methods. This study is a retrospective cohort that included 457 patients with symptoms of dyspepsia, who underwent upper endoscopy at Evanston and Glenbrook Northshore Hospital from June 2003 to October 2007. A total of 556 samples were reported with some patients having more than one test over the time period. The CLOtest was performed first on the gastric specimen and from that specimen, the DNA was isolated and the one-step multiplex PCR was performed. Results. By M-PCR testing, H. pylori was detected in 143 (52.2%) of 274 cases in the control group and 130 (46.1%) of 282 cases in patients on PPI treatment (P = 0.1746). The CLOtest detected the presence of H. pylori in 4 (1.4%) of 282 cases from the same group receiving PPI treatment and 29 (10.6%) of 274 cases from the group not taking a PPI (P ≤ 0.0001). Conclusion. Our PCR is sensitive enough to detect the presence of H. pylori despite being on PPI treatment.

Is Helicobacter pylori resident or transient in the human oral cavity?

Helicobacter pylori colonizes the stomachs of at least half of the world's human population. The role of the oral cavity in this colonization is not clear and there are, to date, no comprehensive data that clearly demonstrate the isolation of this bacterium from the oral cavity. The aim of this study was to evaluate the prevalence of H. pylori in the oral cavity of 15 patients who tested positive for H. pylori. A comprehensive dental examination of all patients was conducted. Samples were taken from supragingival and subgingival plaque, saliva, periapical exudates and tongue swabs. All samples were taken before the application of antibiotics. A total of 163 oral samples were investigated by PCR using two different H. pylori-specific primer pairs. A PCR inhibition control using a modified plasmid was always included for the most specific primer pair. In addition, a culture technique was used to confirm PCR results. Despite a PCR detection limit of 10(2) bacteria ml(-1), out of 14 patients, H. pylori could not be detected in any of the samples taken. In one patient, H. pylori-positive PCR signals were obtained in two samples using only one primer pair. H. pylori could not be cultivated from these two PCR-positive samples; therefore, no correlation to oral colonization status could be established. This study challenges the misleading preconception that H. pylori resides in the human oral cavity and suggests that this bacterium should be considered transient and independent of the oral status. To date, positive PCR results for H. pylori in the oral cavity have been overestimated and not critically interpreted in literature.

Detection of clarithromycin resistance in Helicobacter pylori following noncryogenic storage of rapid urease tests for 30 days

OBJECTIVE

Traditional Helicobacter pylori (H. pylori) eradication therapy has been undermined by increasing antimicrobial, especially clarithromycin, resistance. Susceptibility testing in some areas is difficult to achieve or unavailable. We aimed to determine whether gastric biopsy specimens stored at room temperature for rapid urease test (RUT) were suitable for clarithromycin susceptibility testing of H. pylori.

METHODS

After 30 days of storage at room temperature, DNA was extracted from gastric biopsies present in RUTs (Hpfast). H. pylori status and clarithromycin susceptibility were evaluated using H. pylori-specific polymerase chain reaction (PCR) for ureA, vacA, and allele-specific primer-PCR of the 23S rRNA genes. The PCR results were compared with histology, RUT, and culture results. H. pylori positive was defined as RUT and either culture or histology positive; H. pylori negative as RUT, culture and histology negative.

RESULTS

Samples from 31 patients were evaluated; 11 were H. pylori positive including 9 by culture; seven of which had allele-specific primer-PCR results from the RUT specimen for the detection of mutations of the 23S rRNA gene. When both tests were available, culture and PCR results were concordant in 7 cases. In 15 of the 20 histology, RUT and culture negative patients, three PCR were negative. In one patient, all of the three tests were positive; and in three only the 23S rRNA was positive and in one only ureA was positive.

CONCLUSION

Gastric biopsy specimens stored in the gel of RUT for 30 days can be used for molecular testing to confirm the diagnosis of H. pylori infection and test for clarithromycin susceptibility.

The effectiveness of systemic eradication therapy against oral Helicobacter pylori

BACKGROUND

Helicobacter pylori infection is associated with numerous gastroduodenal diseases. The oral cavity could be a potential extragastric reservoir for H. pylori, and oral H. pylori might cause gastric reinfection after the eradication therapy. The aim of the study was to evaluate the presence of H. pylori in oral cavity of patients with gastric H. pylori infection and to examine the effectiveness of the eradication therapy against H. pylori in stomach and in the oral cavity.

METHODS

Fifty-six patients with chronic periodontitis and gastric H. pylori were enrolled in the study. Gastric H. pylori infection was determined using (13) C-urea breath test before and 3 months after eradication therapy. The presence of the oral H. pylori was assessed using polymerase chain reaction before and 3 months after eradication therapy. The 1-week eradication therapy consisted of amoxycilin 1 g, clarithromycin 500 mg, and proton pump inhibitor 20 mg twice a day.

RESULTS

Of 56 subjects with gastric infection, 23 (41.1%) harbored H. pylori in the oral cavity. Eradication rate in stomach was 78.3%, whereas in the oral cavity, H. pylori was not detected from any sample after the eradication therapy.

CONCLUSION

Almost half of the patients with gastric H. pylori harbored the bacterium in the oral cavity. After the eradication therapy, H. pylori was not detected in the oral cavity, what suggests high effectiveness of the therapy protocol in the oral cavity, or it is possible that oral H. pylori is of a transient character.

Differential effect of Helicobacter pylori eradication on time-trends in brady/hypokinesia and rigidity in idiopathic parkinsonism

BACKGROUND

We examine the effect of eradicating Helicobacter in idiopathic parkinsonism (IP). Marked deterioration, where eradication-therapy failed, prompted an interim report in the first 20 probands to reach de-blinding. The null-hypothesis, "eradication has no effect on principal outcome, mean stride length at free-walking speed," was rejected. We report on study completion in all 30 who had commenced post-treatment assessments.

METHODS

This is a randomized, placebo-controlled, parallel-group efficacy study of eradicating biopsy-proven (culture and/or organism on histopathology) Helicobacter pylori infection on the time course of facets of IP, in probands taking no, or stable long-t(1/2), anti-parkinsonian medication. Persistent infection at de-blinding (scheduled 1-year post-treatment) led to open active eradication-treatment.

RESULTS

Stride length improved (73 (95% CI 14-131) mm/year, p = .01) in favor of "successful" blinded active over placebo, irrespective of anti-parkinsonian medication, and despite worsening upper limb flexor rigidity (237 (57-416) Nm x 10(-3)/year, p = .01). This differential effect was echoed following open active, post-placebo. Gait did not deteriorate in year 2 and 3 post-eradication. Anti-nuclear antibody was present in all four proven (two by molecular microbiology only) eradication failures. In the remainder, it marked poorer response during the year after eradication therapy, possibly indicating residual "low-density" infection. We illustrate the importance of eradicating low-density infection, detected only by molecular microbiology, in a proband not receiving anti-parkinsonian medication. Stride length improved (424 (379-468) mm for 15 months post-eradication, p = .001), correction of deficit continuing to 3.4 years. Flexor rigidity increased before hydrogen-breath-test positivity for small intestinal bacterial overgrowth (208 (28-388) Nm x 10(-3), p = .02), increased further during (171 (67-274), p = .001) (15-31 months), and decreased (136 (6-267), p = .04) after restoration of negativity (32-41 months).

CONCLUSION

Helicobacter is an arbiter of progression, independent of infection-load.

Helicobacter pylori colonization of the adenotonsillar tissue: fact or fiction?

OBJECTIVE

The transmission of the gastric pathogen Helicobacter pylori involves the oral route. Molecular techniques have allowed the detection of H. pylori DNA in samples of the oral cavity, although culture of H. pylori from these type of samples has been sporadic. Studies have tried to demonstrate the presence of H. pylori in adenotonsillar tissue, with contradictory results. Our aim was to clarify whether the adenotonsillar tissue may constitute an extra gastric reservoir for H. pylori.

METHODS

Sixty-two children proposed for adenoidectomy or tonsillectomy were enrolled. A total of 101 surgical specimens, 55 adenoid and 46 tonsils, were obtained. Patients were characterized for the presence of anti-H. pylori antibodies by serology. On each surgical sample rapid urease test, immunohistochemistry, fluorescence in situ hybridization (FISH) with a peptide nucleic acid probe for H. pylori, and polymerase chain reaction-DNA hybridization assay (PCR-DEIA) directed to the vacA gene of H. pylori were performed.

RESULTS

Thirty-nine percent of the individuals had anti-H. pylori antibodies. Rapid urease test was positive in samples of three patients, all with positive serology. Immunohistochemistry was positive in samples of two patients, all with negative serology. All rapid urease test or immunohistochemistry positive cases were negative by FISH. All samples tested were negative when PCR-DEIA for H. pylori detection was used directly in adenotonsillar specimens.

CONCLUSIONS

The adenotonsillar tissue does not constitute an extra gastric reservoir for H. pylori infection, at least a permanent one, in this population of children. Moreover, techniques currently used for detecting gastric H. pylori colonization are not adequate to evaluate infection of the adenotonsillar tissues.

Detection of Helicobacter pylori in biofilms by real-time PCR

Helicobacter pylori is a cause of peptic ulcer disease and a causative agent of gastric cancer. Currently, a possible waterborne route of transmission or a possible survival in drinking water biofilms is discussed. H. pylori, like many other bacterial strains, has the ability to enter the viable but nonculturable state (vbnc) in case of unfavorable conditions. Therefore it is necessary to develop new analysis tools for vbnc bacteria. We established a fast and reliable method to detect H. pylori in drinking water biofilms by quantitative real-time PCR which makes it redundant to use difficult cultivation methods for nonculturable bacteria. With this method it was possible to identify water biofilms as a niche for H. pylori. The real-time PCR analysis targets the ureA subunit of the Helicobacter pylori urea gene which showed high specificity and sensitivity. The quantitative real-time PCR was used to detect H. pylori in biofilms of different age, unspiked and spiked with predetermined levels of cells. The drinking water biofilms were generated in a silicone-tube model. The DNA-sequences for probe and primers showed no cross-homologies to other related bacteria and it was possible to detect less than 10 genomic units of H. pylori. This novel method is a useful tool for a fast screening of drinking water biofilms for H. pylori. The results suggest that drinking water biofilms may act as a reservoir for H. pylori which raises new concerns about the role of biofilms as vectors for pathogens like Helicobacter pylori.