Diagnosis of helicobacter pylori infection by polymerase chain reaction: is it worth it?

The aim of this study was to determine to what degree polymerase chain reaction (PCR) was superior to histology and culture, and whether a noncommercial urease test was of value, in detecting Helicobacter pylori in gastric biopsy specimens. Gastric biopsy specimens from the antrum and corpus of 134 consenting patients were subjected to PCR, targeting the glmM (ureC) gene, histology, culture, and a rapid urease test. PCR detected H. pylori in the biopsy specimens from 59 patients. All methods showed a high degree of sensitivity and specificity, but histology gave 2 false-negatives, and culture and the urease test gave 1 false-negative compared with PCR. PCR of a glmM gene segment was superior to the other methods for the detection of H. pylori infection and was comparable to histology in terms of cost. Nevertheless, in this study, histology and culture were found to be relatively reliable methods for examining gastric biopsy specimens.     

Is the remarkable contradiction between histology and 14C urea breath test in the detection of Helicobacter pylori due to false-negative histology or false-positive 14C urea breath test?

We assessed the diagnostic value of the 14C urea breath test (UBT) in the detection of Helicobacter pylori compared with histology and the rapid urease test (RUT). The study included 68 patients (22 men and 46 women) with dyspeptic symptoms. H. pylori status was evaluated by 14C UBT, RUT and histology. Sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy were determined for 14C UBT and for RUT. Histology revealed dense yeast-like micro-organisms in the biopsy specimens in all patients with false-positive results by 14C UBT (n = 8), a significantly higher proportion than in patients with negative 14C UBT (five of 31). The low specificity of the H. pylori 14C UBT should not be neglected by accepting histology results as false-negative. Gastric mucosal colonization by yeast-like micro-organisms with urease activity can account for the high frequency of false-positive results for 14C UBT.     

Oral colonization of Helicobacter pylori: risk factors and response to eradication therapy

BACKGROUND: Dental plaque is considered by some to be a secondary reservoir for Helicobacter pylori and thus responsible for gastric reinfection. The aim of this study was to investigate whether testing dental plaque using a rapid urease test (CLOtest) can be used to determine gastric H. pylori status. METHODS: We investigated dental plaque colonization by H. pylori and its correlation with gastric infection in 75 dyspeptic patients. CLOtest was used to determine H. pylori positivity. RESULTS: Tests for H. pylori were positive in dental plaque samples from 68 patients and in stomach samples from 65 patients. The sensitivity of using CLOtest in dental plaque to determine gastric H. pylori status was 89.7%, with a diagnostic accuracy of 86.7%. Gastric eradication was achieved in 83% of patients, but efforts to eradicate dental plaque colonization were unsuccessful in all patients. CONCLUSION: Using CLOtest to detect H. pylori in dental plaque is a reliable first-line diagnostic approach for gastric H. pylori infection. Dental plaque might be a sanctuary for H. pylori, leading to gastric recurrence.     

Laboratory tests for the evaluation of Helicobacter pylori infections.

Helicobacter pylori is a highly motile bacterium with multiple unipolar flagella, and it produces the urease enzyme. The flagella and urease are the virulence factors of H. pylori. H. pylori often establishes a chronic infection in the stomach that may lead to gastric and duodenal ulcers, gastric cancers, gastric lymphomas, and other gastrointestinal diseases. There are several different invasive and noninvasive clinical laboratory tests for H. pylori. Laboratory testing is not indicated in asymptomatic patients and should be considered only if treatment of H. pylori infection is planned. Invasive tests for H. pylori, such as tissue histology, culture, and rapid urease tests, are used if an endoscopy is performed on the patient. The noninvasive tests for H. pylori, such as enzyme antibody and urea breath tests, are recommended in patients whose symptoms do not warrant endoscopy. The urea breath test is very useful and is recommended to evaluate effectiveness in the eradication and treatment of H. pylori infections. Nucleic acid tests can complement other diagnostic procedures, and are useful in evaluating fixed biopsy tissue, environmental samples, gastric juices, oral secretions, and stool samples.     

Quantitative correlation of Helicobacter pylori stool antigen (HpSA) test with the severity of H. pylori-related gastritis

The Helicobacter pylori (H. pylori) load in both stomach and stool and the resulting severity of gastritis are important criteria in validating the status of H. pylori infection. We aimed to assess the reliability of the H. pylori stool antigen (HpSA) test for the primary diagnosis of H. pylori infection by calculating the best cut-off value to obtain the highest sensitivity and specificity in dyspeptic patients. We also investigated the correlation of HpSA test with the severity of gastritis and H. pylori load. The H. pylori statuses of 95 patients were evaluated by the positivity of both rapid urease test and microscopic detection of H. pylori in biopsy specimens, 88 subjects of whom were H. pylori positive. The sensitivity and specificity of the HpSA test were 51.1% (45/88) and 100% (7/7), respectively, according to the manufacturer's recommended cut-off value of 0.16. However, with the best cut-off value of 0.048, calculated by receiver operator characteristics analysis, the sensitivity of the test increased to 92.0% (81/88) with the same specificity. High values of the HpSA test were correlated with high scores of corpus H. pylori load and the severity of antrum and corpus inflammation (p < 0.05). With the best cut-off value of the HpSA test, the primary diagnosis of H. pylori infection can be made with higher sensitivity and specificity. The HpSA test is a helpful tool that evaluates the severity of H. pylori infection and the degree of gastric inflammatory activity and gastric H. pylori load.     

Helicobacter pylori and Helicobacter heilmannii in children. A Bulgarian study

The aim of the study was to evaluate the prevalence of Helicobacter pylori and Helicobacter heilmannii among 321 children. Gram staining, urease test and culture were performed. Of all patients, 52.6% were H. pylori positive and 0.3% were H. heilmannii positive. H. pylori infection was associated with chronic gastritis in 57.1%, with duodenal ulcer in 75% and with non-ulcer dyspepsia in 25.6%. This infection was more frequent in children aged 11-18 years than in younger patients. Rapid urease test, culture and direct Gram staining showed 42.3, 96.5 and 78.2% sensitivity and 93.2, 100 and 84.6% specificity, respectively. H. pylori was detected in 60.2% of fresh versus 52.8% of frozen specimens and in 64.8% in gastric biopsy versus 25% in gastric mucus specimens. H. pylori growth was detected after nine to 10 days in 6.2% and after 11 days in 1.2%. Culture exhibited the best accuracy of the three diagnostic methods. Frozen biopsy specimens gave reliable H. pylori detection unlike gastric mucus specimens. Eleven days of incubation for H. pylori is recommended. The study confirms an early acquisition of H. pylori infection in Bulgaria. The incidence of H. heilmannii infection in childhood is uncommon but clinically important.     

端粒酶表达与幽门螺杆菌感染关系的临床观察

目的　探讨端粒酶表达与幽门螺杆菌 (HP)感染在胃癌发生发展过程中的关系及临床意义。方法　用PCR- EL ISA法、病理组织学方法及快速尿素酶试验检测 111例各种胃病变的胃粘膜活检标本中端粒酶活性和 HP感染情况。结果　胃癌组织中端粒酶表达阳性率为 85 % ,明显高于癌前病变 (2 1.2 % ) ,癌周正常组织 (10 % )及浅表性胃炎(0 ) ,差异非常显著 (P<0 .0 1)。 HP感染率在胃癌组为 5 5 % ,癌前病变组为 6 3.5 %。胃癌及癌前病变端粒酶阳性率在 HP阳性组 (90 .9%、2 4.2 % )高于 HP阴性组 (77.8%、15 .8% ) ,但统计学处理无显著性差异 (P>0 .0 5 )。结论　本研究结果显示 ,检测端粒酶活性有助于胃癌的早期诊断。胃癌及癌前病变组织端粒酶表达与幽门螺杆菌感染无关。     

粪便抗原检测对幽门螺杆菌感染的诊断价值

目的：研究幽门螺杆菌粪便抗原（HpSA）检测诊断幽门螺杆菌（HP）感染的临床应用价值。方法：采用ELISA法检测98例因上消化道症状接受胃镜检查病人的HpSA,同时进行细菌培养,快速尿素酶试验和^14C－尿素呼气试验检查。将后三项检查中二项阳性或细菌培养一项阳性作为诊断HP感染的金标准。结果：金标准诊断HP感染,阳性54例,阴性44例。金标准阳性的54例中,HpSA检测阳性为51例,阴性为3例;金标准阴性的44例中,HpSA检测阴性为42例,阳性为2例。HpSA检测诊断HP感染的敏感度94．4％（51／54）,特异度95．5％（42／44）,准确度94．9％（93／98）,阳性预测值96．2％（51／53）,阴性预测值93．3％（42／45）。结论：HpSA检测有较高的敏感性和特异性,是一种简便可靠,非侵入性的诊断HP感染的方法,易于临床推广。     

检测幽门螺杆菌粪便抗原的临床价值——附94例检测结果分析

目的 对检测幽门螺杆菌粪便抗原诊断幽门螺杆菌（Ｈｐ）感染的准确性进行临床评价。方法：采用酶联免疫分析法检测９４例因上消化道接受胃镜检查病人的幽门螺杆菌便抗原（ＨｐＳＡ）,以快速尿素酶、组织学检测结果作为诊断ＨＰ的标准。结果：在快速尿素酶、组织学检查均阳性的４４例中,ＨＰＳＡＳ的阳性的有４２例,阴性的有２例;而在快速尿毒酶、组织学检查阴性的５０例中,ＨＰＳＡ检测为阴性的有４９例,阳性的有１例。ＨＰＳ     

Evaluation of urinary rapid test for Helicobacter pylori in general practice

There is increasing interest in noninvasive tests for the diagnosis of Helicobacter pylori (H. pylori) infection. One such test, a urine-based rapid test kit (RAPIRUN H. pylori Antibody, Otsuka Pharmaceutical Co., Ltd.) for detection of antibody to H. pylori, has been developed and is considered ideal. In addition to its noninvasiveness and safe handling-due to use of urine as a sample-the assay procedure used for the urinary rapid test is very simple. Only 10-20 minutes are required to complete an assay, and no instruments are needed. The aim of this study was to examine the clinical usefulness of this urine-based rapid test. A total of 189 patients, including 76 patients with gastroduodenal disease, were recruited. A pair of random single-void urine and serum samples was collected from each of the 189 patients, and antibody to H. pylori in the urine and serum samples was measured using the urine-based rapid test kit and three commercially available serum-based ELISA kits. For the patients with gastroduodenal disease, invasive diagnostic methods using endoscopic biopsy specimens such as culture, histology, and rapid urease test were also performed. The sensitivity, specificity, and accuracy of the urinary rapid test were evaluated on the basis of the three serum ELISA results or the invasive diagnostic results. In addition, various urinalyses were performed, and the effects of substances existing in urine on the urinary rapid test results were examined. Of the 189 patients, the urinary rapid test was positive for 110 (58.2%), negative for 78 (41.3%), and invalid for only one patient (0.5%). Based on the three serum-based ELISA results, the sensitivity, specificity, and accuracy of the urinary rapid test were 93.7, 88.9, and 92.2%, respectively. On the basis of the biopsy-based test results, the sensitivity of the urinary rapid test was 100% and its accuracy (95.2%) was equivalent or superior to that of each serum-based ELISA. In addition, no significant differences were observed between groups positive and negative on urinary rapid testing in any urinalysis parameter examined. The novel urinary rapid test kit evaluated in this study enables simple, rapid, and accurate diagnosis of H. pylori infection, and is an ideal test method for point-of-care testing.     

Detection of Helicobacter pylori infection: when to perform which test?

This paper reviews current diagnostic techniques for Helicobacter pylori infection and critically questions their value under different diagnostic circumstances. As long as we do not have general treatment recommendations for H. pylori infection, endoscopy is still the basis for primary diagnosis because it assesses therapy indications. In addition, histology characterizes the gastroduodenal lesions observed and may reveal malignant diseases. New rapid urease tests from the biopsies are inexpensive, simple, and quick giving results reliably within 1 h. Culturing H. pylori from gastric samples after therapy failure and testing the strains for antimicrobial susceptibility is becoming increasingly important with higher prevalence of drug resistances. Nonendoscopic tests are more convenient to the patient. Serological tests inexpensively detect circulating IgG or IgA antibodies. However, inspite of the cost attractiveness, serology might be problematic in indicating present H. pylori infection. The tests of choice for noninvasive monitoring therapy success or failure are the 13C-urea breath test and the faecal antigen immunoassay. Both tests are also of value for first diagnosis in children when endoscopy is not indicated. In the future, serological detection of virulence factors and polymerase chain reaction with molecular fingerprinting might help to identify H. pylori strains with high pathogenicity or antibiotic resistance.     

Incidence of Gastric Metaplasia and Helicobacter pylori Infection in Duodenal Bulb - With Specific Reference to Patients With Duodenal Ulcers

We determined the incidence of gastric metaplasia in the duodenal bulb of duodenal ulcer patients and the Helicobacter pylori (H. pylori) infection rate at sites with gastric metaplasia. Biopsy of the duodenal bulb showed the presence of gastric metaplasia in 61 of 86 patients (71%) overall and in 18 of 47 patients (38.3%) who had gastrectomy at an early gastric cancer. The histological diagnosis of H. pylori infection showed good agreement (83.3%) with the result of the rapid urease test, indicating that H. pylori occurs in regions with gastric metaplasia. This finding suggests that H. pylori infects gastric metaplasia in the duodenal bulb, causing mucosal injury, which is then transformed into duodenal ulcers. The exact mechanism by which gastric metaplasia is caused is unknown, but it is believed to occur in the transitional zone in the duodenal mucosa.     

14C-尿素呼气试验检测幽门螺杆菌感染的临床应用

目的探讨14C-尿素呼气试验(14C-UBT)检测幽门螺杆菌(Hp)感染的临床应用价值。方法选取128例患者因上消化道症状接受胃镜检查患者,以快速尿素酶试验(RUT)和血清HP抗体胶体金试验联合检测作为诊断HP感染的"金标准",评价14C-UBT诊断Hp感染的敏感性、特异性和准确性。结果金标准阳性70例中,14C-UBT检测阳性为67例,阴性为3例;金标准阴性58例中,14C-UBT检测阴性为56例,阳性为2例。14C-UBT检测诊断Hp感染的敏感度95.7%(67/70),特异度96.6%(56/58),准确性96.1%(123/128),阳性预测值97.1%(67/69),阴性预测值94.9%(56/59)。14C-UBT、RUT、血清Hp抗体胶体金试验等3种方法的敏感性、特异性、准确性经非参数检验法检验,差异均无统计学意义。结论14C-UBT有较高的敏感性和特异性,是一种简便可靠,非侵入性的诊断Hp感染的方法,易于临床推广。     

PC R 检测技术在幽门螺杆菌诊断检测中的应用探讨

目的探寻聚合酶联反应(PCR)检测技术在幽门螺杆菌(H .pylori ,Hp)检测中的应用.方法通过对该院消化内科疑是患胃或十二指肠溃疡、胃或胃窦炎、胃癌患者于胃镜下取其病变部位组织标本,进行 Hp分离培养、PCR体外扩增,患者同时做尿素酶试验、血清学抗体检查,将结果进行比较分析.结果170份病例标本中,分离培养67例、尿素酶试验82例、Hp抗体检查152例、PCR扩增144例阳性.阳性率分别为39.4%、48.2%、89.5%、84.7%.以细菌培养为金标准,则尿素酶试验、抗体检查、PCR灵敏度分别为88.1%、89.5%、98.5%,特异性分别为94.6%、77.4%、81.7%.这4种检测方法中,灵敏度最高的为PCR基因扩增法,其次为抗体检查和尿素酶试验;特异性最高的为尿素酶试验,其次为PCR扩增和抗体检查.结论 PCR试验特异性和灵敏度均较高,可以用作Hp感染的确诊、基因分型、流行病学调查、微量取材等的检查.     

Helicobacter pylori Infection in Endoscopic Biopsy Specimens of Gastric Antrum: Laboratory Diagnosis and Comparative Efficacy of Three Diagnostic Tests

Aims and objectives The present study was undertaken to compare the diagnostic yield of three available test procedures for detecting Helicobacter pylori (H. pylori) infection in endoscopic biopsies.Methods H. pylori infection was sought in 150 patients referred for upper gastrointestinal (GI) endoscopy. Multiple (about six) biopsy specimens were taken from pyloric antrum in each patient. Two biopsy specimens were subjected to one minute endoscopy room test - OMERT (a modified form of urease test), two were sent for histopathological analysis, where multiple sections were subjected to Giemsa staining and two were sent for microbiological evaluation after Gram's staining of heat fixed biopsy material.Results H. pylori positivity using histology, microbiology and OMERT was observed to be 33%, 30% and 27% respectively. However, overall 40% patients were infected when the results from three test procedures were combined, as H. pylori positivity was repeated more than once by these procedures separately. Histology was found to be superior to other two tests in our study, especially when multiple sections were examined, for the distribution of the organism was patchy. Amongst the infected, H. pylori was seen in only 30% of all 3-8 sections cut from a biopsy, whereas in 70% it was noted in a single section only.Conclusion The study revealed that histology has the highest detection rate and can be chosen as the "gold standard" amongst the three low cost test procedures available at present in our setup.     

Identification of Helicobacter Pylori in stomach contents

Development of noninvasive methods for the diagnosis of Helicobacter pylori infection is an important problem. We investigated the possibility of detecting the bacterium in gastric juice. Noninvasive methods (bacteriological and urease test) for detection of H. pylori in gastric aspiration biopsy specimens are proposed.     

Diagnosis of the infection by the Helicobacter pylori through stool examination: Method standardization in adults

Objectives

Infection caused by Helicobacter pylori (H. pylori) is one of the most common causes of chronic infection in the world. The presence of the infection is strongly associated with the neoplasia of the gastrointestinal tract, and its diagnosis is easily made by means of invasive or non-invasive methods. Among such methods, the H. pylori antigen detection in stool through ELISA technique is easily performed and it is an alternative to endoscopy in children, since this exam is not usually indicated in this age group. The aim of the current study is to establish the standardization of the ELISA method for the detection of H. pylori in stool specimens in Brazil.

Design and methods

Patients between 18 and 70 years of age were randomly selected in the gastroenterology ambulatory center at Faculdade de Medicina do ABC between 2007 and 2009. They all answered a questionnaire to investigate possible dyspeptic symptoms and then underwent endoscopy and detection of H. pylori through no more than 4 methods. Besides the gastric biopsy, established as the gold standard test, the urease test, the stool ELISA test and serology were also methods applied.

Results

The sensitivity and specificity of the exams in this sample were respectively 87.2% and 44% for the stool ELISA test, 41.9% and 64% for serology, 65.6% and 58.8% for the urease test and 100% and 80.8% for the clinical analysis.

Conclusions

The ROC curve showed a good correlation between the compared methods. In Brazil the standardization of the ELISA test for the detection of H. pylori in stool specimens constitutes a non-invasive diagnostic alternative.     

The evaluation of diagnostic methods for the detection of Helicobacter pylori in gastric biopsy specimens

PCR is a rapid, sensitive and accurate method for the specific detection of Helicobacter pylori from gastric biopsy specimens. In our study, 104 gastric tissue specimens from symptomatic adult patients were examined by staining, culture, PCR and nested PCR methods for detection of H. pylori. According to our results, positivity was achieved in 24% (25/104) with Giemsa staining, 34% (36/104) with histopathology, 36% (38/104) with PCR and 41% (43/104) with nested PCR respectively, whereas H. pylori was isolated in only 33% (35/104) of the cultures on the biopsy specimens. Both the sensitivity and the positive predictive value of the nested PCR method were 100%, and both the specificity and negative predictive value were 98%. As a conclusion, our results suggest the nested PCR as a highly valuable method in the detection of H. pylori with a reasonably high sensitivity and specificity.     

Detection and evaluation of salivary antibodies to Helicobacter pylori in dyspeptic patients

Helicobacter pylori infection is one of the most prevalent infections in humans. The high prevalence and the association with peptic ulceration and gastric cancer require simple and non-invasive methods for the diagnosis of the infection. Detection of salivary anti-H. pylori IgG antibodies has advantages compared with those on serum. In this study, salivary immunoglobulin G response to H. pylori was evaluated in 100 consecutive dyspeptic patients by enzyme-linked immunosorbent assay (ELISA), in comparison with culture and histopathologic examination of gastric biopsy specimens obtained at endoscopic procedures and assessed the accuracy of salivary diagnosis of the infection. The overall sensitivity and specificity of the test were 87 and 73%, respectively. These results suggest that saliva testing for H. pylori antibodies could be used reliably for screening dyspeptic patients in general practice, especially in children in whom venesection is more difficult.     

Urease test of the gastric content deposits for diagnosis of Helicobacter pylori infection in the gastric mucosa

A rapid urease test was applied to the examination of the deposit of gastric juice for diagnosing H. pylori in the gastric mucosa. Two hundred and twenty patients blindly randomized were examined in a case control study. The standard rapid urease test kit Jatrox-H.p.-Test (Rohm Pharma, Germany) was used to determine urease activity in the deposit of gastric juice and duodenal [n = 110 (Group 1)] and gastroduodenal [n = 110 (Group 2)] mucosae. Giemsa staining was employed as a comparison method to examine H. pylori infection in the gastric and duodenal mucosae. The availability of regions of duodenal metaplasia was confirmed by periodic acid-Schiff and alcian blue (Serva) staining tests (pH 1.0 and 2.5, respectively). The results of evaluation of the efficiency of the rapid urease test of gastric juice deposit and gastric and duodenal mucosae in Groups 1 and 2 were as follows: sensitivity (SE) (0.97, 0.99, 0,96), specificity (SP) (0.97, 0.97, 0.99), prevalence (0.64, 0.67, 0.24), test accuracy (TA) (0.96, 0.98, 0.98), negative (0.95, 0.97, 0.99) and positive (0.98, 0.99, 0.96) predictive values; positive (38.8, 33.0, 96.0) and negative (0.03, 0.01, 0.04) likelihood ratios. It is expedient to employ the rapid urease test for the diagnosis of H. pylori infection in the stomach (Se 96-99%, Sp 97%, TA 97-98%). When the test of gastric juice deposit and gastric biopsy is positive, the probability of gastric H. pylori availability is 98-99%. When the test is negative (the probability of H. pylori absence is 95-97%), duodenal biopsy is made. When the test of duodenal biopsy is positive, the probability of H. pylori availability is 96%. When it is negative, the probability of H. pylori absence is 99%. An algorithm of use of the rapid urease test to diagnose H. pylori in different intestinal parts (stomach, duodenum) has been developed.