Methodology and transport medium for collection of Helicobacter pylori on a string test in remote locations

Prevalence of Helicobacter pylori Infection and Diagnostic Methods in the Middle East and North Africa Region

Background and Objectives:Helicobacter pylori (H. pylori) infection is common worldwide and may cause gastroduodenal complications, including cancer. In this review, we examine the prevalence and distribution of various H. pylori genotypes and the risk factors for H. pylori infection, particularly in the Middle East and North Africa (MENA) region. We also introduce different global screening methods and guidelines and compare them to those currently in use in the MENA region. Materials and Methods: We searched the Google Scholar, PubMed, and Saudi Digital Library (SDL) databases for clinical trials and articles published in English. The data collection was mainly focused on MENA countries. However, for H. pylori genotypes and diagnostic methods, studies conducted in other regions or reporting global practices and guidelines were also included to allow a comparison with those in the MENA region. We also included studies examining the prevalence of H. pylori infection in healthy participants. Results:H. pylori infection is highly prevalent in the MENA region, mainly because of the accumulation of risk factors in developing countries. Herein, we highlight a lack of good quality studies on the prevalence of various H. pylori genotypes in the MENA region as well as a need for standard diagnostic methods and screening guidelines. Due to the complications associated with H. pylori, we recommend routine screening for H. pylori infection in all gastroenterology patients admitted in the MENA region. Conclusion: Concerted effort will first be required to validate affordable, non-invasive, and accurate diagnostic methods and to establish local guidelines with adapted cut-off values for the interpretation of the test results.

New transport medium for cultural recovery of Helicobacter pylori

We developed a new transport medium (GESA--Helicobacter pylori transport medium [publication no. WO/2014/019696, patent pending no. PCT/EP2013/002292; Liofilchem s.r.l., Roseto degli Abruzzi, Teramo, Italy]) for recovery of Helicobacter pylori from gastric biopsy samples. GESA transport medium, in a semisolid state, provides the optimal conditions for maintaining the viability of the microorganism over time. The efficacy of the transport medium was assessed through in vitro and ex vivo experiments. We were able to recover different suspensions of H. pylori ATCC 43629 and H. pylori 13 A in GESA transport medium stored at 4 °C for up to 10 days. In particular, with a starting inoculum of ∼ 10(5) CFU, after 7 days of storage, 150 ± 25 CFU and 40 ± 7 CFU of the reference and clinical strains were detected, respectively. H. pylori colonies were isolated from gastric specimens taken from both the antrum and the fundus in 68 (90.66%) of 75 urea breath test (UBT)-positive patients. Moreover, GESA transport medium allowed the recovery and isolation of H. pylori colonies from additional biopsy samples from 13 of the 75 detected subjects at up to 10 days of biopsy sample storage at 4 °C. Finally, GESA transport medium preserved its characteristics when stored at 4°C for 1 year from its preparation, thus allowing good recovery of H. pylori. GESA transport medium can be considered a standardized transport medium with high performance that optimizes the recovery rate of H. pylori grown by culture.

A review of Helicobacter pylori diagnosis, treatment, and methods to detect eradication

Helicobacter pylori (H. pylori) affects nearly half of the world’s population and, thus, is one of the most frequent and persistent bacterial infections worldwide. H. pylori is associated with peptic ulcer disease, gastric ulcers, mucosa-associated lymphoid tissue lymphoma, and gastric cancer. Various diagnostic methods exist to detect infection, and the choice of one method or another depends on several factors, such as accessibility, advantages and disadvantages of each method, cost, and the age of patients. Once H. pylori infection is diagnosed, the clinician decides whether treatment is necessity, according to the patient’s clinical condition. Typically, eradication of H. pylori is recommended for treatment and prevention of the infection. Cure rates with the standard triple therapy are acceptable, and effective quadruple therapies, sequential therapies, and concomitant therapies have been introduced as key alternatives to treat H. pylori infection. In this work, we review the main diagnostic methods used to identify H. pylori infection and to confirm eradication of infection. In addition, key factors related to treatment are reviewed.

Use of the noninvasive entero-test in the detection of Helicobacter pylori in children in an endemic area in Colombia

BACKGROUND AND OBJECTIVE

Gastric infection with Helicobacter pylori (H pylori), a strong risk factor for gastric cancer, is highly prevalent in children residing in the Colombian Andes. We aimed to validate the use of the Entero-test to culture and genotype H pylori strains from asymptomatic Colombian children.

METHODS

Children (ages 10-15 years, n = 110, 80 of which were H pylori positive by the urea breath test [UBT]) were subjected to the Entero-test, and strings were cultured and/or used for DNA extraction for polymerase chain reaction (PCR). These children had been treated for H pylori in 2007. A second population of children (ages 10-15 years, n = 95),which had not been previously treated, was also subjected to the Entero-test.

RESULTS

Of UBT-positive children in the treated group, 29 of 80 (36%) Entero-test samples were H pylori culture positive; 29 additional string extracts were tested by PCR for the H pylori virulence factors cagA and vacA. PCR from cultures and extracts yielded a sensitivity of 74% and specificity of 87%. In the untreated group, 16 of 94 UBT-positive children (17%) produced Entero-tests that were culture positive. Fifty-eight of 94 (62%) string extracts were PCR positive for cagA and/or vacA. In previously treated children, H pylori strains were more often the less virulent vacA s2 (P = 0.001), m2 (P = 0.006), and i2 genotypes (P = 0.039).

CONCLUSIONS

The Entero-test may be used as a noninvasive test to detect H pylori in asymptomatic children residing in high-risk areas for gastric cancer. Treatment of H pylori in children was associated with less virulent genotypes.

Helicobacter pylori eradication in Western Australia using novel quadruple therapy combinations

BACKGROUND

Helicobacter pylori eradication rates with standard triple therapy are declining worldwide. The optimal management of H. pylori is evolving and new treatment combinations for antibiotic resistant H. pylori strains are required, especially for patients with penicillin allergy.

AIM

To review the effectiveness of alternative antibiotic combinations and necessity of pre-antibiotic sensitivity testing.

METHODS

A total of 310 consecutive patients who had failed at least one course of standard 7-day triple therapy initially prescribed by their physicians were included in this study between year 2007 and 2011. Antibiotics were prescribed based on pre-antibiotic sensitivity tests and, if any, patient's allergy to penicillin.

RESULTS

In 98.7% of the patients' samples, H. pylori was successfully cultured. The proportion resistant to clarithromycin and metronidazole was 94.1% and 67.6% respectively, with 65% resistant to both. For the in-house primary quadruple therapy, with Proton pump inhibitor, Amoxicillin, Rifabutin and Ciprofloxacin (PARC), H. pylori was successfully eradicated in 95.2% of patients. For patients allergic to amoxicillin, an alternative quadruple therapy using Proton pump inhibitor, Bismuth subcitrate, Rifabutin and Ciprofloxacin (PBRC) gave an eradication rate of 94.2%. Patients needing alternative salvage therapy were given novel personalised combinations consisting of bismuth, rifabutin, tetracycline or furazolidone; the eradication rate was 73.8%.

CONCLUSIONS

Patients who present with antibiotic resistant H. pylori can be confidently treated with PARC, PBRC or other personalised salvage therapies. These regimens can be used when treatment options are limited by penicillin allergy. Pre-treatment H. pylori antibiotic sensitivity tests contributed to the high eradication rate in this study.

Helicobacter pylori: diagnosis and treatment

PURPOSE OF REVIEW

Multiple diagnostic methods and treatment strategies have been developed to detect and treat the Helicobacter pylori infection. Many of them have stood the test of time; others lost their value with the introduction of new test and treatment modalities. This review focuses on the current diagnostic methods and their clinical implications, as well as on established and novel treatment strategies.

RECENT FINDINGS

The increasing antimicrobial resistance has resulted in a decline of the success rate of recommended eradication regimens. The current guidelines recommend as first-line treatment clarithromycin, amoxicillin or metronidazole, and proton pump inhibitor twice daily, but recent studies have demonstrated an increasing eradication failure with these regimens. Several treatment modifications have been adopted regarding duration and combination of substances.

SUMMARY

The currently recommended first-line treatments are effective and well tolerated. In areas with high antimicrobial resistance rates, new antibiotic combinations and modifications in the sequence of drug administration are proposed as alternative treatment options to standard triple therapy. Future treatment strategies have to focus on regional antimicrobial resistance adopted treatment selection and the development of new antibiotics.

Methods to detect Helicobacter pylori: from culture to molecular biology

Since the first successful attempts of growing Helicobacter pylori, a variety of tests for detecting infection with this pathogen has been described. These tests may be classified as invasive and noninvasive or minimally invasive tests. Conventional tests such as histology and culture still play a major role in the diagnostic spectrum. Culture continues to be the only test allowing for a comprehensive analysis of pathogen characteristics and susceptibility to antibiotics. Urea breath test is the gold standard among noninvasive tests, with both stool antigen test and serology as appropriate substitutes or alternatives in specific situations. Among the multiple potential uses of molecular tests, noninvasive determination of resistance to antibiotics is of particular interest.

Thoughts about populations with unexpected low prevalences of Helicobacter pylori infection

Helicobacter pylori is one of the few remaining major pathogens that accompanied humans on their travels from Africa. A recently published study reports the unexpected finding of a low H. pylori prevalence among pregnant women in Zanzibar (Farag, T.H., Stolzfus, R.J., Khalfan, S.S., Tielsch, J.M., 2007. Unexpectedly low prevalence of Helicobacter pylori infection among pregnant women on Pemba Island, Zanzibar. Trans. R. Soc. Trop. Med. Hyg. 101). The apparent epidemiology of higher prevalence with higher socioeconomic status and decrease with age are unprecedented. As with many 'unexpected' events, a search of the literature reveals evidence of low prevalence populations in Java and Malaysia, with clues dating back to the mid-twentieth century. Why some populations apparently lost H. pylori infection remains an open question. However, the tools needed to resolve the dilemma are readily available and we hope investigators will soon rise to the challenge.

Diagnosis of Helicobacter pylori infection

A growing interest in non-invasive tests for the detection of Helicobacter pylori has been observed recently, reflecting a large number of studies published this year. New tests have been validated, and the old ones have been used in different clinical situations or for different purposes. Stool antigen tests have been extensively evaluated in pre- and post-treatment settings both in adults and children, and the urea breath test has been studied as a predictor of bacterial load, severity of gastric inflammation, and response to eradication treatment. Several studies have also explored the usefulness of some serologic markers as indicators of the gastric mucosa status. With regard to invasive tests, molecular methods are being used more and more, but the breakthrough this year was the direct in vivo observation of H. pylori during endoscopy.

Helicobacter pylori diagnosis and management

H pylori is a global human pathogen and is the major cause of gastritis and the gastritis-associated diseases: gastric ulcer, duodenal ulcer, gastric cancer, and primary gastric B-cell lymphoma (MALToma). Although several reliable diagnostic tests are widely available, the ideal regimen for treating the infection re-mains to be established. The current first-line or legacy triple therapy regimens fail in 20% to 40% of patients. Causes of treatment failure include antibiotic resistance, poor compliance, short (7-10 days) duration of therapy, and drug-related side effects. Fourteen-day triple therapy has an approximately 12% better cure rate than does 7-day therapy; therefore, shorter durations can no longer be recommended. Recent studies confirmed older observations that the success rate of legacy triple regimens (PPI plus two antibiotics) can be improved if the duration is extended to 14 days or if a third antibiotic is given. Sequential therapy (PPI plus amoxicillin followed by a PPI plus clarithromycin plus metronidazole) requires further evaluation although the concept appears very promising and therapy should probably replace the legacy triple therapies. More studies are needed to examine doses, durations, and the need for sequential administration of the drugs, which extends the duration to 14 days. Nonetheless, sequential quadruple therapy probably should replace the legacy triple therapies. Classic quadruple therapy contains bismuth, a PPI, 1500 mg of metronidazole, and 1500 mg of tetracycline. It provides the highest average eradication rates and in many regions should be considered as the initial approach. Confirmation of eradication using noninvasive diagnostic tests, such as a urea breath test or stool antigen assay, is now the standard of care. The diagnosis of latent or symptomatic H pylori like the diagnosis of latent or symptomatic syphilis, always should prompt treatment. Because of decreasing cure rates, new and improved therapies are needed.