Helicobacter pylori infection--management from a European perspective

Rapid identification of Helicobacter pylori and assessment of clarithromycin susceptibility from clinical specimens using FISH

Helicobacter pylori remains one of the most common bacterial infections worldwide. Clarithromycin resistance is the most important cause of H. pylori eradication failures. Effective antibiotic therapies in H. pylori infection must be rapidly adapted to local resistance patterns. We investigated the prevalence of clarithromycin resistance due to mutations in positions 2142 and 2143 of 23SrRNA gene of H. pylori by fluorescence in situ hybridisation (FISH), and compared with culture and antimicrobial susceptibility testing in 234 adult patients with dyspepsia who were enrolled. Antrum and corpus biopsy specimens were obtained for rapid urease test, histopathology and culture. Epsilometer test was used to assess clarithromycin susceptibility. H. pylori presence and clarithromycin susceptibility were determined by FISH in paraffin‐embedded biopsy specimens. We found that 164 (70.1%) patients were positive for H. pylori based on clinical criteria, 114 (69.5% CI 62.5–76.6%) were culture positive, and 137 (83.5% CI 77.8–89.2%) were FISH positive. Thus the sensitivity of FISH was significantly superior to that of culture. However specificity was not significantly different (91.4 versus 100.0%, respectively). The resistance rate to clarithromycin for both antrum and corpus was detected in H. pylori‐positive patients; 20.2% by FISH and 28.0% by E‐test.The concordance between E‐test and FISH was only 89.5% due to the presence of point mutations different from A2143G, A2142G or A2142C. We conclude that FISH is significantly more sensitive than culture and the E‐test for the detection of H. pylori and for rapid determinination of claritromycin susceptibility. The superior hybridisation efficiency of FISH is becoming an emerging molecular tool as a reliable, rapid and sensitive method for the detection and visualisation of H. pylori, especially when the management of H. pylori eradication therapy is necessary. This is particularly important for the treatment of patients with H. pylori eradication failure.

Potential role of probiotics in the management of gastric ulcer

Gastric ulcer is one of the most common chronic gastrointestinal diseases characterized by a significant defect in the mucosal barrier. Helicobacter pylori (H. pylori) infection and the frequent long-term use of non-steroidal anti-inflammatory drugs are major factors involved in gastric ulcer development. Acid inhibitors and antibiotics are commonly used to treat gastric ulcer. However, in the last few decades, the accumulating evidence for resistance to antibiotics and the side effects of antibiotics and acid inhibitors have drawn attention to the possible use of probiotics in the prevention and treatment of gastric ulcer. Probiotics are live microorganisms that when administered in adequate amounts confer health benefits on the host. Currently, the available experimental and clinical studies indicate that probiotics are promising for future applications in the management of gastric ulcers. This review aims to provide an overview of the general health benefits of probiotics on various systemic and gastrointestinal disorders with a special focus on gastric ulcer and the involved cellular and molecular mechanisms: i) Protection of gastric mucosal barrier; ii) upregulation of prostaglandins, mucus, growth factors and anti-inflammatory cytokines; iii) increased cell proliferation to apoptosis ratio; and iv) induction of angiogenesis. Finally, some of the available data on the possible use of probiotics in H. pylori eradication are discussed.

Antimicrobial susceptibility and clarithromycin resistance patterns of Helicobacter pylori clinical isolates in Vietnam

Helicobacter pylori is a gastric pathogen that causes several gastroduodenal disorders such as peptic ulcer disease and gastric cancer.  Eradication efforts of H. pylori are often hampered by antimicrobial resistance in many countries, including Vietnam.  Here, the study aimed to investigate the occurrence of antimicrobial resistance among H. pylori clinical isolates across 13 hospitals in Vietnam.  The study further evaluated the clarithromycin resistance patterns of H. pylori strains.  In order to address the study interests, antimicrobial susceptibility testing, epsilometer test and PCR-based sequencing were performed on a total of 193 strains isolated from patients, including 136 children (3–15 years of age) and 57 adults (19–69 years of age).  Antimicrobial susceptibility testing showed that the overall resistance to amoxicillin, clarithromycin, levofloxacin, metronidazole, and tetracycline was 10.4%, 85.5%, 24.4%, 37.8%, and 23.8% respectively.  The distribution of minimum inhibitory concentrations (MICs) of clarithromycin-resistant strains was 85.5% with MIC >0.5 μg/mL.  The majority of the clarithromycin resistant isolates (135 of 165 subjects) have MICs ranging from 2 μg/mL to 16 μg/mL.  Furthermore, sequencing detection of mutations in 23S rRNA gene revealed that strains resistant and susceptible to clarithromycin contained both A2143G and T2182C mutations.  Of all isolates, eight clarithromycin-resistant isolates (MIC >0.5 μg/mL) had no mutations in the 23S rRNA gene.  Collectively, these results demonstrated that a proportion of clarithromycin-resistant H. pylori strains, which are not related to the 23S rRNA gene mutations, could be potentially related to other mechanisms such as the presence of an efflux pump or polymorphisms in the CYP2C19 gene.  Therefore, the present study suggests that providing susceptibility testing prior to treatment or alternative screening strategies for antimicrobial resistance is important for future clinical practice.  Further studies on clinical guidelines and treatment efficacy are pivotal for successful eradication of H. pylori infection.

Gastroprotective effects and antimicrobial activity of Lithraea molleoides and isolated compounds against Helicobacter pylori

ETHNOPHARMACOLOGICAL RELEVANCE

Lithraea molleoides (Vell.) Engl. (Anacardiaceae) is a medicinal plant traditionally used in South America to treat various ailments, including diseases of the digestive system.

AIM OF THE STUDY

To evaluate the in vivo antiulcer and antimicrobial activities against Helicobacter pylori of L. molleoides and its isolated compounds.

MATERIALS AND METHODS

Methanolic extract 250 and 500 mg/kg, (LmE 250 and LmE 500, respectively) and infusions, 10 g and 20 g en 100mL (LmI 10 and LmI 20, respectively) of L. molleoides was evaluated for antiulcer activity against 0.6N HCl, 0.2N NaOH, 200mg/kg acetilsalicilic acid and absolute ethanol-induced gastric ulcers in rats. The degree of erosion in the glandular part of the stomach was assessed from a scoring system. Acute toxicity in mice was also evaluated. The antiulcer effect of the isolated compounds (catechol, mannitol, rutin, gallic acid, ferulic acid and caffeic acid, 100mg/kg) was evaluated against absolute ethanol-induced gastric ulcers in rats. The anti-Helicobacter pylori activity of L. molleoides and isolated compounds was performed using broth dilution methods.

RESULTS

The LmE 250, LmE 500, LmI 10 and LmI 20 produced significant inhibition on the ulcer index in 0.6N HCl, 0.2N NaOH, 200mg/kg acetilsalicilic acid and absolute ethanol- induced gastric ulcers in rats. The isolated compounds, catechol, mannitol, rutin, ferulic acid and caffeic acid were active in absolute ethanol- induced gastric ulcers in rats. L. molleoides and different compounds showed antimicrobial activity in all strains tested. The lowest MIC value (0. 5 μg/mL) was obtained with catechol in six of eleven strains assayed. No signs of toxicity were observed with doses up to 2g/kg in an acute toxicity assay.

CONCLUSION

These findings indicate that L. molleoides displays potential antiulcerogenic and antimicrobial activities and the identification of active principles could support the use of this plant for the treatment of digestive affections.