Diagnosis of Helicobacter pylori infection: which is the best test? The stool test

A Novel Stool PCR Test for Helicobacter pylori May Predict Clarithromycin Resistance and Eradication of Infection at a High Rate

Clarithromycin-based regimens are commonly used as a first-line therapy for Helicobacter pylori-positive patients; however, resistance to clarithromycin has led to treatment failures. The aim of this study was to evaluate the feasibility of using stool samples to detect the presence of H. pylori DNA while concurrently detecting mutations associated with resistance to clarithromycin. For this purpose, total DNA was extracted from 294 raw stool specimens from H. pylori-positive and -negative patients. TaqMan real-time PCR amplification was used to detect the presence of H. pylori as well as to predict the phenotype of the organism and the related outcome for patients treated with clarithromycin. Clarithromycin resistance was determined upon analysis of the PCR result. Patients were also tested by a urea breath test and were subjected to esophagogastroduodenoscopy, followed by histology, culture, and a rapid urease test, in order to obtain a consensus patient infection status. Of 294 total stool samples, 227 were deemed true positive. The sensitivity of H. pylori detection by PCR was 93.8%. Of 213 true-positive samples that were sequenced, 36.2% showed point mutations associated with clarithromycin resistance (A2142C, A2142G, A2143G). The final correlation of the mutant genotypes as determined by sequencing with the eradication of infection was 86%. We found that Helicobacter pylori DNA can be detected in human stool specimens with high sensitivity and can therefore be used to determine the presence of the bacterium without obtaining a biopsy sample. Moreover, genotypic resistance to clarithromycin can be predicted without obtaining a biopsy sample, facilitating the choice of the right therapeutic approach.

H. PYLORI INFECTION, ENDOSCOPIC, HISTOLOGICAL ASPECTS AND CELL PROLIFERATION IN THE GASTRIC MUCOSA OF PATIENTS SUBMITTED TO ROUX-EN-Y GASTRIC BYPASS WITH CONTENTION RING: a cross sectional endoscopic and immunohistochemical study

BACKGROUND

Morbid obesity treatment through vertical gastroplasty Roux-en-Y gastric bypass initially used a contention ring. However, this technique may create conditions to the development of potentially malign alterations in the gastric mucosa. Although effective and previously performed in large scale, this technique needs to be better evaluated in long-term studies regarding alterations caused in the gastric mucosa.

OBJECTIVE

To analyze the preoperative and postoperative endoscopic, histological and cell proliferation findings in the gastric antrum and body mucosa of patients submitted to the Roux-en-Y gastric bypass with a contention ring.

METHODS

We retrospectively evaluated all patients submitted to Roux-en-Y gastric bypass with a contention ring with more than 60 months of postoperative follow-up. We compared the preoperative (gastric antrum and body) and postoperative (gastric pouch) gastric mucosa endoscopic findings, cell proliferation index and H. pylori prevalence. We evaluated cell proliferation through Ki-67 antibody immunohistochemical expression.

RESULTS

In the study period, 33 patients were operated with the Roux-en-Y gastric bypass using a contention ring. We found a chronic gastritis rate of 69.7% in the preoperative period (gastric antrum and body) and 84.8% in the postoperative (gastric pouch). H. pylori was present in 18.2% of patients in the preoperative period (gastric antrum and body) and in 57.5% in the postoperative (gastric pouch). Preoperative cell proliferation index was 18.1% in the gastric antrum and 16.2% in the gastric body, and 23.8% in the postoperative gastric pouch. The postoperative cell proliferation index in the gastric pouch was significantly higher (P=0.001) than in the preoperative gastric antrum and body. Higher cell proliferation index and chronic gastritis intensity were significantly associated to H. pylori presence (P=0.001 and P=0.02, respectively).

CONCLUSION

After Roux-en-Y gastric bypass with contention ring, there was a higher chronic gastritis incidence and higher cell proliferation index in the gastric pouch than in the preoperative gastric antrum and body. Mucosa inflammation intensity and cell proliferation index in the postoperative gastric pouch were associated to H. pylori presence and were higher than those found in the preoperative gastric antrum and body mucosa.

Helicobacter pylori infection in clinical practice: probiotics and a combination of probiotics + lactoferrin improve compliance, but not eradication, in sequential therapy

BACKGROUND

Sequential therapy (ST) seems to offer higher success rates than triple therapy (TT) in the eradication of Helicobacter pylori (H. pylori) infection. However, from the standpoint of therapeutic compliance, there is no difference between the two treatments. Adjuvant treatment (especially with probiotics (PB) and lactoferrin (LF)) has often improved compliance and eradication rates in patients subjected to TT, while ST had never been used in association with adjuvants.

METHODS

Over a period of 2 years, we randomized and divided 227 consecutive adult patients with H. pylori infection into three groups. The patients were given ST with the addition of adjuvants, as follows: group A (ST + placebo), group B (ST + LF + PB), and group C (ST + PB). Our goal was to assess therapeutic compliance, so we prepared a questionnaire to help determine the severity of the side effects. We also determined the eradication rates for the groups.

RESULTS

Patients with ST + placebo had the worst compliance as compared with the other two groups in terms of the absence of symptoms (p < .001 between B and A; p = .001 between C and A) and the presence of intolerable symptoms (p = .016 between B and A; p = .046 between C and A). The differences between the values for the treated groups and those for the placebo group were statistically significant. On the other hand, there was no statistically significant difference in compliance between groups B and C. The eradication rate was similar for the three groups.

CONCLUSIONS

Probiotics associated with ST provide optimum therapeutic compliance compared with the placebo and, despite the need to take a larger number of tablets, they should be taken into consideration as an adjuvant to therapy for H. pylori infection. The addition of LF to the PB did not bring about any further improvements in compliance. As compared with the placebo, the eradication rate of ST did not improve by adding LF + PB or by using PB alone.

Helicobacter pylori infection: sequential therapy followed by levofloxacin-containing triple therapy provides a good cumulative eradication rate

BACKGROUND

In the eradication of H. pylori infection, even today, the main international guidelines recommend the triple therapy as first-line regimen, although its effectiveness is clearly decreasing. As second-line treatment, the bismuth-containing quadruple therapy is the most used regimen, although several other therapies are studied. The Italian guidelines recommend, alternatively, sequential therapy or triple therapy as first-line treatment and levofloxacin-containing triple therapy as second-line regimen. We wanted to assess the overall eradication rate of Helicobacter pylori infection in two therapeutic rounds following the Italian guidelines in clinical practice.

MATERIALS AND METHODS

We treated 231 consecutive Helicobacter pylori-positive patients by sequential therapy and we verified the eradication 8-10 weeks after treatment by stool antigen test. Patients positive for stool antigen test received levofloxacin-containing triple therapy, as second-line therapy, according to Italian Guidelines and they were again submitted to the fecal test 8-10 weeks after the end of treatment.

RESULTS

In the first-line regimen, we obtained an eradication rate of 92.6%, in the second-line of 75.0% and as cumulative result we achieved a 97.8% of eradication, in per-protocol analysis.

CONCLUSIONS

Sequential therapy as first-line and levofloxacin-containing triple therapy as second-line represent a good combination to eradicate Helicobacter pylori infection in only two rounds.

"Cervia II Working Group Report 2006": guidelines on diagnosis and treatment of Helicobacter pylori infection in Italy

Proper management of Helicobacter pylori infection in clinical practice--when supported by evidence-based data--is expected to produce substantial cost-efficacy advantages. This consideration has prompted the Cervia Working Group to organise a meeting of experts to update the National Guidelines on the diagnosis and treatment of H. pylori infection in Italy. Recommendations in the new European Guidelines were considered in the National setting, here in the light of factors such as the incidence of gastric cancer and gastric lymphoma, the accessibility to different diagnostic tools, the prevalence of bacterial resistance against antibiotics, and the availability of different drugs. The main revisions in respect to the previous guidelines include H. pylori eradication in non-ulcer dyspepsia patients and in non-steroidal, anti-inflammatory drug users, as well as in patients with idiopathic thrombocytopenic purpura and iron deficiency anaemia. The stool antigen test is now accepted as a valid test for confirmation of H. pylori eradication following therapy. New therapeutic approaches have been recommended for both first- (sequential therapy) and second-line (levofloxacin-based) treatment in our country.

Stool antigen test for the diagnosis of Helicobacter pylori infection: a systematic review

Our aim was to review systematically the diagnostic accuracy of the Helicobacter pylori stool antigen test. Bibliographical searches were performed in several electronic databases and abstracts from congresses up to May 2003. Eighty-nine studies (10,858 patients) evaluated the stool antigen test in untreated patients. Mean sensitivity, specificity, positive predictive value and negative predictive value were 91%, 93%, 92% and 87%, respectively. Analysis of the eight studies (1399 patients) in which pretreatment evaluation of the monoclonal stool antigen test was performed showed better (p < .001) results (96%, 97%, 96% and 97%, respectively), with a clearer distinction between positive and negative results. Thirty-nine studies (3147 patients) evaluated the stool antigen test for the confirmation of H. pylori eradication 4-8 weeks after therapy, with accuracies of 86%, 92%, 76% and 93% for mean sensitivity, specificity, positive predictive value and negative predictive value, respectively. Results were similar when a gold standard based on at least two methods was used. Relatively low accuracy was reported in some posttreatment studies with the polyclonal stool antigen test. However, excellent results (p < .001) were achieved in all the six studies evaluating the monoclonal stool antigen test 4-8 weeks posttreatment. Results evaluating the stool antigen test < 4 weeks posttreatment are contradictory. Proton-pump inhibitors seem to affect the accuracy of the stool antigen test. Sensitivity and/or specificity in patients with gastrointestinal bleeding may be suboptimal. The stool antigen test performs well in children. Finally, the stool antigen test seems to be a cost-effective method.