Clinical evaluation of a novel molecular diagnosis kit for detecting Helicobacter pylori and clarithromycin-resistant using intragastric fluid

Asia-Pacific Survey on the Management of Helicobacter pylori Infection

BACKGROUND AND AIM

Gastric cancer (GC)-related incidence and mortality rates remain high owing to Helicobacter pylori infection in Asia, and the importance of primary and secondary prevention of GC has been well recognized. We aimed to investigate the extent of overall agreement among clinicians in the Asia-Pacific region regarding the management of H. pylori infection.

METHODS

The Upper Gastrointestinal (GI) Focus Group of the Asian Pacific Association of Gastroenterology-Emerging Leaders Committee developed an international survey, which was distributed to 98 clinicians in the Asia-Pacific region, compromising an online questionnaire focusing on the management of H. pylori infection.

RESULTS

Participants responded from Japan (15, 15.3%), Hong Kong (15, 15.3%), Thailand (33, 33.7%), Vietnam (23, 23.5%), Malaysia (4, 4.1%), Singapore (3, 3.1%), and others (5, 5.1%). The most common first-line eradication regimen was clarithromycin (CAM) triple therapy, including proton pump inhibitor (PPI), amoxicillin (AMPC), and CAM (64.3%) for 14 days (70.4%). The most common second-line eradication regimen was levofloxacin (LVX) triple therapy, including PPI, AMPC, and LVX (22.4%) for 14 days (67.3%). Eradication therapy was deemed necessary for all asymptomatic adults and minors (aged ≤ 17 years) currently infected with H. pylori by 81.6% and 64.3% of respondents, respectively, with 82.7% considering upper GI endoscopy for GC screening useful in the secondary prevention of GC.

CONCLUSION

There appears to be a growing consensus among clinicians, acknowledging the necessity of eradication therapy. We anticipate that this study will establish a new benchmark in preventive medicine aimed at eradicating GC in the Asia-Pacific region.

Comparative analysis of the detection of antibiotic genotypic resistance with gastric mucosa, gastric fluid, and fecal samples in patients with Helicobacter pylori infection

Genotypic methods for detecting antibiotic resistance in Helicobacter pylori infection offer a rapid, convenient, and accurate approach for tailored therapy. However, existing studies predominantly examine single sample types and lack comparative analyses across different samples. This study comprehensively detects and compares genotypic resistance to clarithromycin and levofloxacin in gastric mucosa, gastric fluid, and fecal samples from the same patients. The study enrolled 183 participants, comprising 124 H. pylori-positive and 59 H. pylori-negative patients. All participants provided fecal samples and underwent gastroscopy for the collection of gastric mucosa and gastric fluid. Real-time PCR was employed to detect genotypic resistance to clarithromycin and levofloxacin in conjunction with bacterial culture and antibiotic susceptibility testing. Genotypic resistance detection rates for clarithromycin were 100% in gastric mucosa, 99.2% in gastric fluid, and 79.8% in fecal samples. For levofloxacin, detection rates were 97.6%, 96.8%, and 72.6%, respectively. The results showed that PCR detection for clarithromycin exhibited high sensitivity (0.94-0.95) and specificity (0.88-0.89) across all sample types. However, PCR detection for levofloxacin demonstrated slightly lower sensitivity (0.79-0.89) and specificity (0.79-0.83). The comparison of genotypic resistance results by PCR among the three sample types showed that gastric mucosa and gastric juice exhibited higher consistency, while the consistency between feces and both gastric mucosa and gastric juice was lower. This study confirmed good consistency between genotypic and phenotypic resistance in clarithromycin and levofloxacin. While both gastric mucosa and gastric fluid samples demonstrated high detection performance, the efficiency of detecting fecal samples was constrained by challenges in DNA extraction.

IMPORTANCE

This study, with a large sample size, comprehensively tested both Helicobacter pylori-negative and -positive patients, including rapid urease test, histopathological evaluation and staining, bacterial culture, susceptibility testing, and resistance gene mutation analysis. By simultaneously examining gastric mucosa, gastric juice, and fecal samples from the same individuals, we minimized confounding factors arising from different sample sources, ensuring the reliability of our results. This approach effectively delineated the differences and characteristics in detection performance among different sample types, offering crucial reference data for selecting appropriate detection samples and identifying areas for improvement. The findings revealed robust concordance between genotypic and phenotypic resistance, with both gastric mucosa and gastric juice samples demonstrating excellent detection performance. However, the efficiency of detecting resistance in fecal samples was hampered by challenges in DNA extraction.

Rapid visual detection of Helicobacter pylori and vacA subtypes by Dual-Target RAA-LFD assay

BACKGROUND

Helicobacter pylori (H. pylori) infects over 50% of the global population and is a significant risk factor for gastric cancer. The pathogenicity of H. pylori is primarily attributed to virulence factors such as vacA. Timely and accurate identification, along with genotyping of H. pylori virulence genes, are essential for effective clinical management and controlling its prevalence.

METHODS

In this study, we developed a dual-target RAA-LFD assay for the rapid, visual detection of H. pylori genes (16s rRNA, ureA, vacA m1/m2), using recombinase aided amplification (RAA) combined with lateral flow dipstick (LFD) methods. Both 16s rRNA and ureA were selected as identification genes to ensure reliable detection accuracy.

RESULTS

A RAA-LFD assay was developed to achieve dual-target amplification at a stable 37 °C within 20 min, followed by visualization using the lateral flow dipstick (LFD). The whole process, from amplification to results, took less than 30 min. The 95 % limit of detection (LOD) for 16 s rRNA and ureA, vacA m1, vacA m2 were determined as 3.8 × 10-2 ng/μL, 5.8 × 10-2 ng/μL and 1.4 × 10-2 ng/μL, respectively. No cross-reaction was observed in the detection of common pathogens including Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis, showing the assay's high specificity. In the evaluation of the clinical performance of the RAA-LFD assay. A total of 44 gastric juice samples were analyzed, immunofluorescence staining (IFS) and quantitative polymerase chain reaction (qPCR) were used as reference methods. The RAA-LFD results for the 16s rRNA and ureA genes showed complete agreement with qPCR findings, accurately identifying H. pylori infection as confirmed by IFS in 10 out of the 44 patients. Furthermore, the assay successfully genotyped vacA m1/m2 among the positive samples, showing complete agreement with qPCR results and achieving a kappa (κ) value of 1.00.

CONCLUSION

The dual-target RAA-LFD assay developed in this study provides a rapid and reliable method for detecting and genotyping H. pylori within 30 min, minimizing dependency on sophisticated laboratory equipment and specialized personnel. Clinical validation confirms its efficacy as a promising tool for effectively control of its prevalence and aiding in the precise treatment of H. pylori-associated diseases.

The Accuracy of Melting Curve-Based Multiplex Real-Time PCR for Diagnosing Helicobacter pylori Resistance to Clarithromycin and Levofloxacin in Stool Specimens

AIMS

This study evaluates the accuracy of melting curve-based multiplex real-time PCR (multiplex rt-PCR) on stool samples for diagnosing antibiotic resistance in Helicobacter pylori (H. pylori) compared to E-test and sequencing.

METHODS

Gastric biopsies and stool samples were collected from 385 H. pylori-infected patients. A total of 325 strains were isolated, and genomic DNA was extracted from all 385 stool samples. E-tests were conducted to detect phenotypic resistance for clarithromycin and levofloxacin. Sanger sequencing and multiplex rt-PCR were employed to identify H. pylori 23S rRNA and GyrA mutations.

RESULTS

E-test results indicated that 203 (62.5%) were susceptible to both clarithromycin and levofloxacin, 33 (10.2%) exhibited mono-resistance to clarithromycin, 48 (14.8%) showed mono-resistance to levofloxacin, and 41 (12.6%) had dual resistance to both antibiotics. Compared to E-test results, the sensitivity and specificity of the multiplex rt-PCR method for detecting clarithromycin resistance mutation were 93.2 (95% CI 84.3-97.5) and 87.1% (95% CI 82.2-90.9), respectively. For levofloxacin resistance mutation, the multiplex rt-PCR method showed a sensitivity of 80.7 (95% CI 70.3-88.3) and a specificity of 93.0% (95% CI 88.7-95.8). Compared to Sanger sequencing, the sensitivity and specificity of the multiplex rt-PCR method for detecting clarithromycin resistance mutation were 95.8 (95% CI 90.0-98.4) and 96.0% (95% CI 92.6-98.0), respectively. For levofloxacin resistance mutation, the multiplex rt-PCR method showed a sensitivity of 91.3% (95% CI, 83.1-95.9) and a specificity of 96.1% (95% CI, 92.7-98.0).

CONCLUSION

Genotypic methods, including Sanger sequencing and multiplex rt-PCR, were rapid and reliable for diagnosing clarithromycin and levofloxacin resistance in the stool samples.

Impact of mixed-infection rate of clarithromycin-susceptible and clarithromycin-resistant Helicobacter pylori strains on the success rate of clarithromycin-based eradication treatment

BACKGROUND

Clarithromycin (CAM) resistance is a major contributor to the failure to eradicate Helicobacter pylori (H. pylori). The mixed-infection ratio of CAM-susceptible and CAM-resistant H. pylori strains differs among individuals. Pyrosequencing analysis can be used to quantify gene mutations at position each 2142 and 2143 of the H. pylori 23S rRNA gene in intragastric fluid samples. Herein, we aimed to clarify the impact of the rate of mixed infection with CAM-susceptible and CAM-resistant H. pylori strains on the success rate of CAM-containing eradication therapy.

MATERIALS AND METHODS

Sixty-four H. pylori-positive participants who received CAM-based eradication therapy, also comprising vonoprazan and amoxicillin, were enrolled in this prospective cohort study. Biopsy and intragastric fluid samples were collected during esophagogastroduodenoscopy. H. pylori culture and CAM-susceptibility tests were performed on the biopsy samples, and real-time PCR and pyrosequencing analyses were performed on the intragastric fluid samples. The mutation rates and eradication success rates were compared.

RESULTS

The overall CAM-based eradication success rate was 84% (54/64): 62% (13/21) for CAM-resistant strains, and 95% (39/41) for CAM-sensitive strains. When the mutation rate of the 23S rRNA gene was 20% or lower for both positions (2142 and 2143), the eradication success rate was 90% or more. However, when the mutation rate was 20% or higher, the eradication success rate was lower (60%).

CONCLUSIONS

The mutation rate of the CAM-resistance gene was related to the success of eradication therapy, as determined via pyrosequencing analysis.

Antibiotic resistance of Helicobacter pylori in Nanjing, China: a cross-section study from 2018 to 2023

Background

The increasing prevalence of antibiotic resistance in cases of Helicobacter pylori (H. pylori) infection has emerged as a significant global issue. This study offers a comprehensive examination of the alterations in drug resistance exhibited by H. pylori in the Nanjing region of China during the preceding five years. Another important objective is to investigate the influence of levofloxacin medication history on genotypic and phenotypic resistance.

Methods

This research screened 4277 individuals diagnosed with H. pylori infection between April 2018 and May 2023. The phenotype and genotypic resistance were evaluated using the Kirby-Bauer disk diffusion and PCR method.

Results

The most recent primary resistance rates for metronidazole, clarithromycin, levofloxacin, amoxicillin, furazolidone, and tetracycline were recorded at 77.23% (2385/3088), 37.24% (1150/3088), 27.72% (856/3088), 0.52% (16/3088), 0.19% (6/3088), and 0.06% (2/3088), respectively. For the recent five years, we observed a notable upsurge in the rate of metronidazole resistance and a slight elevation of clarithromycin and levofloxacin resistance. The documented resistance rates to single-drug, dual-drug, triple-drug, and quadruple-drug regimens were 35.39%, 28.32%, 25.72%, and 0.21%, respectively. The prevalence of multidrug-resistant strains escalated, rising from 37.96% in 2018 to 66.22% in 2023. The rate of phenotypic and genotypic resistance rate (57.10% and 65.57%) observed in strains obtained from patients without a levofloxacin treatment history was significantly lower than the rate in strains obtained from those with a history of levofloxacin treatment (88.73% and 94.74%). The prevailing gyrA mutations were primarily N87K (52.35%, 345/659), accompanied by D91N (13.96%, 92/659), and closely followed by D87G (10.77%, 71/659). For gyrA mutations, the 91-amino acid mutants exhibit a higher likelihood of discrepancies between phenotypic and genotypic resistance than the 87-amino acid mutants.

Conclusion

The extent of antibiotic resistance within H. pylori remains substantial within the Nanjing region. If levofloxacin proves ineffective in eradicating H. pylori during the initial treatment, its use in subsequent treatments is discouraged. The employment of levofloxacin resistance genotype testing can partially substitute conventional antibiotic sensitivity testing. Notably, predicting phenotypic resistance of levofloxacin through PCR requires more attention to the mutation type of gyrA to improve prediction accuracy.

Case report: A pediatric case of repeated false-positive urea breath test for Helicobacter pylori without decreased gastric acid secretion

The urea breath test (UBT) is often used to diagnose Helicobacter pylori infection and for its eradication. However, this text can give positive results even for other urease-active bacteria other than H. pylori. Even after the successful eradication of H. pylori, the presence of other urease-active bacteria in the gut and oral cavity can lead to positive UBT results in patients with decreased gastric acid secretion. Herein, a 15-year-old boy was diagnosed with H. pylori infection through the testing and treatment program for H. pylori for third-year junior high-school students in Saga Prefecture initiated in 2016. He underwent triple therapy comprising vonoprazan; however, UBT was found to be positive even after therapy. The results remained positive even after fourth-line eradication therapy. Stool antigen, PCR using gastric fluid, microscopy, culture, and rapid urease tests were all negative. Pepsinogen levels were normal, and none of the findings suggested autoimmune gastritis. Gastric microflora analysis revealed oral flora showing urease activity. UBT is considered useful for determining the successful eradication of H. pylori; however, it may give false-positive results for both H. pylori infection and eradication judgment. Although the patient did not have autoimmune gastritis or decreased gastric acid secretion, it is presumed that oral commensal bacteria showing urease activity inhabited the stomach, resulting in the persistently positive UBT results. In conclusion, repeated false-positive UBT results for H. pylori may occur even without gastric acid hyposecretion. If H. pylori eradication is unsuccessful based on UBT, additional test by stool H. pylori antigen tests should be considered.

Expectations for the Dual Therapy with Vonoprazan and Amoxicillin for the Eradication of H. pylori

Vonoprazan (VPZ) inhibits gastric acid secretion more potently than proton pump inhibitors. Recently, attention has been focused on the dual therapy with VPZ and amoxicillin (AMOX) for the eradication of H. pylori. The dual VPZ/AMOX therapy attains the sufficient eradication rate with lowering the risk of adverse events in comparison with the triple therapy and quadruple therapy. Therefore, the dual VPZ/AMOX therapy is considered a useful eradication regimen for H. pylori infection.