Correlation between positive rate and number of biopsy samples on urease test in childhood Helicobacter pylori infection

Concordance of Helicobacter pylori Detection Methods in Symptomatic Children and Adolescents

BACKGROUND

Helicobacter pylori is the most prevalent chronic bacterial infection globally, acquired mostly during childhood. It is associated with chronic gastritis, peptic ulcer disease, and gastric cancer. Due to challenges in culturing H. pylori, diagnostic reference standards often rely on combining ≥2 non-culture, biopsy-based methods. Histology with Giemsa staining is widely used in clinical settings due to its low cost and reliable performance.

METHODS

This study evaluated the concordance between histology with Giemsa staining as the reference standard and other diagnostic methods, including the rapid urease test (RUT), ureA RT-PCR, 16S sequencing, and anti-H. pylori serum IgG. Positive percent of agreement (PPA), negative percent of agreement (NPA) and concordance kappa index were calculated.

RESULTS

A total of 120 patients (41 positive and 79 negative by Giemsa staining) were analyzed. Among the methods tested, RT-PCR for ureA showed the best performance (PPA = 94.7%, NPA = 98.6%, kappa = 0.939), while RUT underperformed compared with expectations (PPA = 65.9%, NPA = 97.5%, kappa = 0.681). Serology had the lowest performance (PPA = 53.7%, NPA = 96.1%, kappa = 0.548).

CONCLUSIONS

The combination of histology with Giemsa staining and ureA RT-PCR achieved the highest detection rate and strongest agreement.

Antigenic Determinant of Helicobacter pylori FlaA for Developing Serological Diagnostic Methods in Children

The early diagnosis of Helicobacter pylori infection is important for gastric cancer prevention and treatment. Although endoscopic biopsy is widely used for H. pylori diagnosis, an accurate biopsy cannot be performed until a lesion becomes clear, especially in pediatric patients. Therefore, it is necessary to develop convenient and accurate methods for early diagnosis. FlaA, an essential factor for H. pylori survival, shows high antigenicity and can be used as a diagnostic marker. We attempted to identify effective antigens containing epitopes of high diagnostic value in FlaA. Full-sized FlaA was divided into several fragments and cloned, and its antigenicity was investigated using Western blotting. The FlaA fragment of 1345-1395 bp had strong immunogenicity. ELISA was performed with serum samples from children by using the 1345-1395 bp recombinant antigen fragment. IgG reactivity showed 90.0% sensitivity and 90.5% specificity, and IgM reactivity showed 100% sensitivity and specificity. The FlaA fragment of 1345-1395 bp discovered in the present study has antigenicity and is of high value as a candidate antigen for serological diagnosis. The FlaA 1345-1395 bp epitope can be used as a diagnostic marker for H. pylori infection, thereby controlling various gastric diseases such as gastric cancer and peptic ulcers caused by H. pylori.

Worldwide Prevalence and Risk Factors of Helicobacter pylori Infection in Children

Helicobacter pylori is usually acquired during childhood. The reports from the last two decades pointed out a decrease in H. pylori prevalence across geographical areas worldwide compared to previously reported data. Most of the studies performed in America found an overall H. pylori infection prevalence of approximately 50%. The most important risk factors in America include being male, poor adherence or difficult access to treatment, and the lack of in-home water service. Despite the descending trend in prevalence worldwide, the overall prevalence in Africa remains very high (70%). Nevertheless, the prevalence of H. pylori in children without gastrointestinal who underwent screening was reported to be only 14.2%. The main risk factors in Africa are having a traditional pit or no toilet, poverty, birth order, source of drinking water, or being a farmer. Asia seems to have the widest variations in terms of H. pylori prevalence. Several risk factors were reported in Asia to be associated with this infection, such as lower income and educational level, house crowding, rural residence, ethnicity, the use of tanks as water supplies, alcohol drinking, active smoking, eating spicy food or raw uncooked vegetables, poor living conditions and sanitation. The overall prevalence of H. pylori infection in European children is almost 25%. Portugal has the highest prevalence of all European countries at 66.2% in children 13 years of age. The risk factors in European individuals consist of living in rural areas, eating unwashed fruits and vegetables, not washing hands after school, low parental education and unemployment, and short education duration. Further studies are required to identify the precise mechanisms involved in the discrepancies of H. pylori prevalence worldwide.

Changing prevalence of Helicobacter pylori infection in children and adolescents

Helicobacter pylori infection has declined over recent decades. However, its prevalence remains high, and nearly 50% of the global population has been infected. In Korea, seroprevalence has steadily decreased in adults, but the status of H. pylori infection in children is unknown. The current status or trend of H. pylori infection in children is important because it can help estimate H. pylori-related diseases including gastric cancer in later life. In this review, the authors discuss the change in H. pylori infection rate among children and adolescents based on literature reviews and our research.

Diagnosis of Helicobacter pylori infection in clinical practice

Diagnostic tests used to detection Helicobacter pylori are divided into invasive (requiring endoscopy) and non-invasive, direct (bacteriological, histological or molecular detection of the bacterium) and indirect (detection of urease activity of the bacterium or antibodies to it). The choice of the test is determined by the clinical situation, as well as by its availability and cost. The sensitivity of most tests is affected by the use of antisecretory drugs and antibiotics.

Diagnosis of Helicobacter pylori Infection in Children and Adolescents in Korea

Helicobacter pylori plays an important role in the pathogenesis of chronic gastritis, peptic ulcer disease, gastric cancer, and gastric mucosa-associated lymphoid tissue lymphoma. In Korea, the guidelines for the diagnosis and treatment of H. pylori infection in adults were revised in 2013. The European Helicobacter and Microbiota Study Group and Consensus panel released the fifth edition of the Maastricht Consensus Report for the management of H. pylori infection in 2015, and the European Society of Paediatric Gastroenterology, Hepatology and Nutrition and the North American Society of Paediatric Gastroenterology, Hepatology and Nutrition released the updated joint guidelines for children and adolescents in 2016. Considering these recommendations and recent progress in our research and that of other research teams, this study aimed to discuss the diagnostic strategies for H. pylori infection in children and adolescents.

Characterizing antigenic determinants in Helicobacter pylori CagA capable of detecting serum antibodies in children

Helicobacter pylori can persistently colonize the mucosa of the human stomach, resulting in gastric disorders. Endoscopic biopsy for rapid urease test and histopathologic examination are considered as the most accurate diagnostic methods for H. pylori infection. Serological methods are recommended for children because of invasiveness of the diagnosis mentioned above. Here, the cytotoxin-associated gene A protein (Cag A), as an immunodominant antigen, was subdivided to determine which regions harbor antigenicity for humans. CagA was divided into 17 overlapping fragments of ∼400 bp, which were used for the analysis of antigenic determinants. The partial proteins were subjected to immunoblot analysis using pooled serum samples from children with gastric symptoms. A partial recombinant CagA protein containing epitope regions (683-749 amino acids), which were identified in this study, was produced and used for the detection of anti-CagA antibodies and further investigated its serodiagnostic value for determination of H. pylori infection in children. The serum IgG reactivities from children with gastric symptoms were significantly three times more than that of serum samples from children with non-gastric symptoms (P < 0.005). Moreover, the serum IgG reactivities from children showing strong urease activity of gastric biopsies were significantly higher than those with moderate and weak urease activities (P < 0.05). Hence, the partial CagA is a candidate antigen for diagnosis of H. pylori infection.

Helicobacter pylori Antigens Inducing Early Immune Response in Infants

To identify the Helicobacter pylori antigens operating during early infection in sera from infected infants using proteomics and immunoblot analysis. Two-dimensional (2D) large and small gel electrophoresis was performed using H. pylori strain 51. We performed 2D immunoglobulin G (IgG), immunoglobulin A (IgA), and immunoglobulin M (IgM) antibody immunoblotting using small gels on sera collected at the Gyeongsang National University Hospital from 4-11-month-old infants confirmed with H. pylori infection by pre-embedding immunoelectron microscopy. Immunoblot spots appearing to represent early infection markers in infant sera were compared to those of the large 2D gel for H. pylori strain 51. Corresponding spots were analyzed by matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF-MS). The peptide fingerprints obtained were searched in the National Center for Biotechnology Information (NCBI) database. Eight infant patients were confirmed with H. pylori infection based on urease tests, histopathologic examinations, and pre-embedding immunoelectron microscopy. One infant showed a 2D IgM immunoblot pattern that seemed to represent early infection. Immunoblot spots were compared with those from whole-cell extracts of H. pylori strain 51 and 18 spots were excised, digested in gel, and analyzed by MALDI-TOF-MS. Of the 10 peptide fingerprints obtained, the H. pylori proteins flagellin A (FlaA), urease β subunit (UreB), pyruvate ferredoxin oxidoreductase (POR), and translation elongation factor Ts (EF-Ts) were identified and appeared to be active during the early infection periods. These results might aid identification of serological markers for the serodiagnosis of early H. pylori infection in infants.

Joint ESPGHAN/NASPGHAN Guidelines for the Management of Helicobacter pylori in Children and Adolescents (Update 2016)

BACKGROUND

Because of the changing epidemiology of Helicobacter pylori infection and low efficacy of currently recommended therapies, an update of the European Society for Paediatric Gastroenterology Hepatology and Nutrition/North American Society for Pediatric Gastroenterology, Hepatology and Nutrition recommendations for the diagnosis and management of H pylori infection in children and adolescents is required.

METHODS

A systematic review of the literature (time period: 2009-2014) was performed. Representatives of both societies evaluated the quality of evidence using GRADE (Grading of Recommendation Assessment, Development, and Evaluation) to formulate recommendations, which were voted upon and finalized using a Delphi process and face-to-face meeting.

RESULTS

The consensus group recommended that invasive diagnostic testing for H pylori be performed only when treatment will be offered if tests are positive. To reach the aim of a 90% eradication rate with initial therapy, antibiotics should be tailored according to susceptibility testing. Therapy should be administered for 14 days, emphasizing strict adherence. Clarithromycin-containing regimens should be restricted to children infected with susceptible strains. When antibiotic susceptibility profiles are not known, high-dose triple therapy with proton pump inhibitor, amoxicillin, and metronidazole for 14 days or bismuth-based quadruple therapy is recommended. Success of therapy should be monitored after 4 to 8 weeks by reliable noninvasive tests.

CONCLUSIONS

The primary goal of clinical investigation is to identify the cause of upper gastrointestinal symptoms rather than H pylori infection. Therefore, we recommend against a test and treat strategy. Decreasing eradication rates with previously recommended treatments call for changes to first-line therapies and broader availability of culture or molecular-based testing to tailor treatment to the individual child.

Correlations between the CagA Antigen and Serum Levels of Anti-Helicobacter pylori IgG and IgA in Children

We tested correlations between anti-Helicobacter pylori IgG and IgA levels and the urease test, anti-CagA protein antibody, degree of gastritis, and age. In total, 509 children (0-15 years) were enrolled. Subjects were stratified as 0-4 years (n = 132), 5-9 years (n = 274), and 10-15 years (n = 103) and subjected to the urease test, histopathology, ELISA, and western blot using whole-cell lysates of H. pylori strain 51. The positivity rate in the urease test (P = 0.003), the degree of chronic gastritis (P = 0.021), and H. pylori infiltration (P < 0.001) increased with age. The median titer for anti-H. pylori IgG was 732.5 IU/mL at 0-4 years, 689.0 IU/mL at 5-9 years, and 966.0 IU/mL at 10-15 years (P < 0.001); the median titer for anti-H. pylori IgA was 61.0 IU/mL at 0-4 years, 63.5 IU/mL at 5-9 years, and 75.0 IU/mL at 10-15 years (P < 0.001). The CagA-positivity rate was 26.5% at 0-4 years, 36.5% at 5-9 years, and 46.6% at 10-15 years for IgG (P = 0.036), and 11.3% at 0-4 years, 18.6% at 5-9 years, and 23.3% at 10-15 years for IgA (P < 0.001). Anti-H. pylori IgG and IgA titers increased with the urease test grade, chronic gastritis degree, active gastritis, and H. pylori infiltration. Presence of CagA-positivity is well correlated with a high urease test grade and high anti-H. pylori IgG/IgA levels.

[European Registry on the management of Helicobacter pylori infection (Hp-EuReg protocol): The first results of Russian centers]

AIM

To assess the clinical practice of diagnosis and treatment in patients with Helicobacter pylori infection and to compare this practice with the international guidelines in the European Registry on the management of Helicobacter pylori infection, Hp-EuReg protocol), a multicenter prospective observational study initiated by the European Helicobacter and Microbiota Study Group. MATERIALs AND METHODS: The data of 813 patients infected with H. pylori and entered in the Hp-EuReg register by the Russian centers in 2013-2015 were analyzed.

RESULTS

The most common methods for the primary diagnosis of H. pylori infection are histology (40.3%), rapid urease test (35.7%), and serology (17.2%). The duration of H. pylori eradication therapy was 7, 10, and 14 days in 18.0, 49.3, and 25.1%, respectively. To monitor the effectiveness of treatment, the investigators used a histological examination (34%), a urea breath test (27.3%), H. pylori stool antigen (22.8%), and a rapid urease test (16.3%). A serological test was carried out in 2.5% of the cases. No monitoring was done in 13.5% of the patients. The average eradication efficiency was 82.6%. If the therapy was ineffective, 80% of physicians did not intend to prescribe a new cycle of treatment.

CONCLUSION

Significant differences were found between clinical practice and the current guidelines.

Limitations of urease test in diagnosis of pediatric Helicobacter pylori infection

The diagnosis of Helicobacter pylori (H. pylori) infection is usually based on the results of urease test and histology. The urease test known as a simple and cheap method does not need special skills to perform or to read the result. The time needed for the test to turn positive depends on the concentration of bacteria, and the accuracy is up to the density of H. pylori density in the biopsy sample, which is generally lower in children than adolescents and adults. Therefore, there are debates about the sensitivity of the urease test in children. The reason for lower sensitivity of the urease test in children was not identified, but might be related to the low density and patchy distribution of bacteria. In this review, we discuss the limitations of the urease test in children according to age, histology, number of biopsy samples, and biopsy site. In children under 5 years old, the differences in positivity rate when the urease test used one or three biopsy samples, and samples from the antrum or the gastric body, were larger than those in children aged 5-15 years. Thus, three or more biopsy samples from both the antrum and body would improve the sensitivity of H. pylori infection diagnosis in children under 5 years old.

Evaluation of Clinicopathological and Risk Factors for Nonmalignant H. Pylori Associated Gastroduodenal Disorders in Iraqi Patients

AIM:

To determine the risk factors associated with H. pylori infection and possible correlation with clinicopathological parameters.

MATERIAL AND METHODS:

Gastroduodenal biopsies were examined by rapid urease test and Gram staining. Cag A cytotoxin was detected by in situ hybridization.

RESULTS:

Risk of H. pylori acquisition reported as following: Males have 1.38 fold, rural residents have 0.63 fold, Nonsmokers have 0.39 fold, mild smokers have 18 fold, and moderate smokers have 1.4 fold while heavy smokers have 1 fold. A person who’s in contact with animals has 1.52 fold risks. Illiterates and patients with primary education have 5.36 & 3 fold risk respectively. Patients under proton pump inhibitor (PPI) therapy have 1.02 fold. Patients under NSAID therapy have 3.48 fold while nonalcoholic Patients have 0.75 fold. Patients using tap water have 0.45 fold risk. H. pylori infection positively correlated with age, weight loss, and heartburn. H. pylori inversely correlated with endoscopic diagnosis, Cag A positivity, and education level. Cag A positivity correlated with animal contact and NSAID usage.

CONCLUSIONS:

Several life style factors, education, animal contact, using of PPI, and NSAIDs increase the risk of H. pylori infection. Weight loss and heartburn cardinal signs for H. pylori infection. Endoscopic diagnosis and clinicopathological parameters not strictly associated with Cag A positivity.

Epidemiology and Diagnosis of Helicobacter pylori infection

During the period reviewed, prevalence studies were essentially performed in less economically advanced countries and a high prevalence was found. The traditional risk factors for Helicobacter pylori positivity were mostly found. Transmission studied by molecular typing showed a familial transmission. The eventual role of water transmission was explored in several studies with controversial results. Concerning diagnosis, most of the invasive and noninvasive methods used for the diagnosis of H. pylori infection are long standing with efficient performance. The most interesting recent improvements in H. pylori diagnosis include advances in endoscopy, developments in molecular methods, and the introduction of omics-based techniques. Interpretation of old or newer method should take into account the pretest probability and the prevalence of H. pylori in the population under investigation.

Helicobacter pylori infection in pediatrics

This review concerns important pediatric studies published from April 2013 to March 2014. New data on pathogenesis have demonstrated that Th1 type cytokine secretion at the gastric level is less intense in children compared with adults. They have also shown that the most significant risk factor for Helicobacter pylori infection is the parents' origin and frequency of childcare in settings with a high prevalence of infection. A new hypothesis on the positive relationship between childhood H. pylori infection and the risk of gastric cancer in adults has been suggested which calls for an implementation of preventive programs to reduce the burden of childhood H. pylori infection in endemic areas. Several studies have investigated the role of H. pylori infection in iron-deficiency anemia, and results support the role of the bacterium in this condition. Antibiotic resistance is an area of intense research with data confirming an increase in antibiotic resistance, and the effect of CYP2C19 genetic polymorphism on proton-pump inhibitor metabolism should be further investigated as cure rates are lower in extensive metabolizers. Studies confirmed that probiotic supplementation may have beneficial effects on eradication and therapy-related side effects, particularly diarrhea in children.