Usefulness of detection of clarithromycin-resistant Helicobacter pylori from fecal specimens for young adults treated with eradication therapy

Accuracy of Fecal Polymerase Chain Reaction Testing in Clarithromycin-Resistant Helicobacter Pylori: A Systematic Review and Meta-Analysis

INTRODUCTION

The increasing prevalence of clarithromycin (CLA)-resistant Helicobacter pylori(H. pylori) strains poses a significant challenge in the management of H. pylori infections. This systematic review and meta-analysis investigates the diagnostic accuracy of polymerase chain reaction (PCR) in identifying CLA-resistant H. pylori strains in stool.

METHODS

A comprehensive literature search was conducted using PubMed, Embase, and Cochrane databases from database inception to April 30, 2023. Eligible studies evaluated the effectiveness of PCR stool tests in detecting CLA-resistant H. pylori strains in adults (>18-year-old). Studies of pediatric populations, alternative methods to PCR or stool samples, and reference tests other than gastric biopsy were excluded. The bivariate random-effects model was used to pool diagnostic accuracy from the included studies.

RESULTS

The analysis of 11 prospective diagnostic studies with a total of 866 patients showed a pooled sensitivity of 0.97 (95% CI: 0.9-0.99) and a pooled specificity of 0.98 (95% CI: 0.81-1.00). Subgroup analysis based on the used technique demonstrated consistent findings without notable variations. The diagnostic odds ratio was calculated at 1843.92 (95% CI: 134.28-25,321.3). The positive likelihood ratio was determined as 51.02 (95% CI: 4.61-564.5), while the negative likelihood ratio was found to be 0.03 (95% CI: 0.01-0.1).

DISCUSSION

PCR testing for clarithromycin-resistant H. pylori was highly sensitive and specific across studies with proven reliability in clinical practice, particularly in outpatient settings. Their implementation offers cost-effectiveness and the potential for tailored treatment strategies, holding promise for improved patient outcomes.

Hydrogel loop-mediated isothermal amplification for ultra-fast diagnosis of Helicobacter pylori in stool samples without nucleic acid extraction

BACKGROUND

The gastrointestinal diseases caused by Helicobacter pylori (H. pylori) infection made the accurate detection of H. pylori infection more important. Non-invasive methods, such as molecular diagnostic methods, had become a promising method for detection of H. pylori. Stool samples combined with loop-mediated isothermal amplification (LAMP), showed potential practicability for real-time detection. However, complex nucleic acid extraction steps were required to remove the large numbers of amplification inhibitors in stool samples before LAMP reaction. And the limited number of H. pylori made the detection with long reaction time and low sensitivity. The problems mentioned above were urgently to be solved.

RESULTS

In this study, we proposed a strategy for ultra-rapid sensitive detection of H. pylori in stool samples by hydrogel LAMP (hLAMP) without extraction. The hydrogel was combined with stool samples after simple thermal cracking, and amplification spaces were formed in its nanopore structures by nano-localization. The LAMP reaction was accelerated by nano space-localization. Besides, this method based on hLAMP could specifically and sensitively detect as low as 100 CFU/mL H. pylori within 40 min from sampling to result due to good anti-inhibition effect on complex samples of hydrogel. The whole process involved sample simple disposal for 10 min and LAMP reaction for 30 min. Furthermore, the excellent anti-inhibition mechanism of hydrogel was discussed, and the mechanism of hydrogel accelerating LAMP was explored.

SIGNIFICANCE

This is the first application of that hydrogel and LAMP systematically combined to detect H. pylori in stool samples. The developed method had been verified in actual clinical applications that the accuracy rate reached 88.9 % compared with routine histopathology. And it also provided a potential idea for the diagnosis and prevention of H. pylori.

Detection of A2143G, A2142C, and A2142G Point Mutations with Real-Time PCR in Stool Specimens from Children Infected with Helicobacter pylori

Reports have indicated an increasing prevalence of clarithromycin resistance in children relative to adults. Thus, it is important to investigate primary clarithromycin resistance before therapy to avoid treatment failure. A2142G, A2143G, and A2142C point mutations in the peptidyltransferase region of the 23S ribosomal RNA (rRNA) of Helicobacter pylori (H. pylori) strains isolated from children with gastrointestinal symptoms and asymptomatic children were evaluated via real-time polymerase chain reaction (RT-PCR) using fecal DNA samples. The presence of H. pylori was determined using a fecal H. pylori antigen enzyme-linked immunosorbent assay (ELISA) kit from the stools of children (n = 543). A2143G, A2142C, and A2142G point mutations were detected via RT-PCR and confirmed by sequencing the 23S rDNA. Fecal H. pylori antigen testing was positive in 101 symptomatic (49) and asymptomatic (52) children. A significant difference was found between the 0-5- and 5-18-year-old groups in terms of the A2143G and A2142G point mutations (p = 0.001). The A2142C mutation was not detected. There was a significant difference in the A2143G mutation between the symptomatic and asymptomatic 5-18-year-old children (p = 0.019). Macrolides are frequently used to treat upper respiratory tract infections in children due to their selective pressure effect. We suggest that H. pylori strains carrying mutations in the 23S RNA subunit conferring clarithromycin resistance may lead to an intense inflammatory response in the gastric epithelial cells, allowing them to proliferate more rapidly and causing possible diarrhea, halitosis, or abdominal pain in children.

Establishment of a reference panel of Helicobacter pylori strains for antimicrobial susceptibility testing

BACKGROUND

Eradication treatment for Helicobacter pylori gastritis is covered by national health insurance since 2013 in Japan. However, eradication failure due to the increase of antimicrobial resistance has become a serious problem. The present study aims to establish a reference panel of Japanese H. pylori strains for antimicrobial susceptibility testing.

METHOD

A total of 28 strains were collected from 4 medical facilities in Japan. Antimicrobial susceptibility tests (ASTs) to clarithromycin (CLR), amoxicillin (AMX), and metronidazole (MNZ), were used to select standard reference strains. Complete genome sequences were also determined.

RESULTS

Three H. pylori strains (JSHR3, JSHR6 and JSHR31) were selected as standard reference strains by the Japanese Society for Helicobacter Research (JSHR). The minimum inhibitory concentrations (MICs) of the antibiotics against these 3 strains by agar dilution method with Brucella-based horse-serum-containing agar medium were as follows: JSHR3 (CLR 16 μg/ml, AMX 0.032 μg/ml and MNZ 4 μg/ml), JSHR6 (CLR 0.016 μg/ml, AMX 0.032 μg/ml and MNZ 4 μg/ml), and JSHR31 (CLR 16 μg/ml, AMX 1 μg/ml and MNZ 64 μg/ml).

CONCLUSIONS

A reference panel of H. pylori JSHR strains was established. The panel consisted of JSHR6, which was antibiotic-susceptible, JSHR3, which was CLR-resistant, and JSHR31, which was multi-resistant. This reference panel will be essential for standardized ASTs before the optimal drugs are selected for eradication treatment.

Clinical Evaluation of a Novel Stool Antigen Test Using Bioluminescent Enzyme Immunoassay for Detecting Helicobacter pylori

BACKGROUND

BLEIA ™ "EIKEN" Helicobacter pylori antigen (B[EIA]) is based on the bioluminescent enzyme immunoassay (BLEIA) method that was newly developed with high sensitivity in detecting Helicobacter pylori (H. pylori) antigen in feces.

METHODS

In the project for H. pylori screening and treatment in Saga Prefecture in 2019, 141 students received the stool H. pylori antigen test as a secondary test. For 141 students, a comparative test was conducted between B (EIA) and extracorporeal diagnostic agents that were marketed in Japan as of 2019. The detection performance of H. pylori ATCC43504 standard strain and H. pylori antigen in commercial human fecal specimens were conducted.

RESULTS

The comparison of B (EIA) with Quick Chaser ^TM H. pylori (Q [IC]) revealed positive and negative concordance ratios of B (EIA) to Q (IC) of 100.0% (110/110) and 71.0% (22/31), respectively. A comparative test was conducted between B (EIA) and extracorporeal diagnostic agents that were marketed in Japan as of 2019, and B (EIA) was most sensitive on "detecting H. pylori antigen of ATCC43504 standard strain" and "detecting H. pylori antigen in commercial human fecal specimens," compared with other kits. Nine dissociated specimens that were negative for Q (IC) and positive for B (EIA) were confirmed. The measured value of B (EIA) in the dissociation samples were 1.3-87.4 cutoff index in the range that can be evaluated as negative by other fecal H. pylori antigen test kits, all the dissociation samples were H. pylori antigen-positive cases, and finally the cause of result divergence was presumed as false negative due to insufficient sensitivity of Q (IC).

CONCLUSION

B (EIA) that is based on the BLEIA method, which applies firefly luciferase luminescence, is more sensitive than stool antigen test kits that are currently marketed in Japan and is very useful in diagnosing H. pylori infection, especially in situations where noninvasive tests are preferred, such as in children.

Polymerase chain reaction-based tests for detecting Helicobacter pylori clarithromycin resistance in stool samples: A meta-analysis

BACKGROUND

Helicobacter pylori (H. pylori) infection is closely associated with the etiology of a variety of gastric diseases. The effective eradication of H. pylori infection has been shown to reduce the incidence of gastric carcinoma. However, the rate of H. pylori eradication has significantly declined due to its increasing resistance to antibiotics, especially to clarithromycin. Therefore, the detection of clarithromycin resistance is necessary prior to the treatment of H. pylori. Although many studies have been conducted on the use of polymerase chain reaction (PCR)-based tests to detect clarithromycin resistance in stool samples, no accurate data on the feasibility of these tests are available. Here, we performed a meta-analysis to assess the feasibility of these noninvasive tests.

AIM

To evaluate the reliability of PCR-based tests for detecting H. pylori clarithromycin resistance in stool samples.

METHODS

We searched PubMed, Medline, Embase, and other databases for articles that evaluated the value of the PCR analysis of stool samples for detecting the resistance of H. pylori to clarithromycin. We collected cross-sectional studies that met the inclusion criteria. Diagnostic accuracy measures were pooled using a random-effects model. The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Subgroup analysis was also conducted according to PCR type, purification technique, reference standard, mutation site, sample weight, number of patients, and age group, and the clinical utility of diagnostic tests was evaluated using the Likelihood Ratio Scatter Graph.

RESULTS

Out of the 1818 identified studies, only 11 met the eligibility criteria, with a total of 592 patients assessed. A meta-analysis of the random-effect model showed that PCR-based analysis of stool samples had high diagnostic accuracy for detecting clarithromycin resistance in patients infected with H. pylori. The combined sensitivity was 0.91 [95% confidence interval (CI): 0.83-0.95], Q = 30.34, and I² = 67.04, and the combined specificity was 0.97 (95%CI: 0.62-1.00), Q = 279.54, and I² = 96.42. The likelihood ratio for a positive test was 33.25 (95%CI: 1.69-652.77), and that for a negative test was 0.10 (95%CI: 0.05-0.18), with an area under the curve of 0.94. The diagnostic odds ratio was 347.68 (95%CI: 17.29-6991.26). There was significant statistical heterogeneity, and the sub-analyses showed significant differences in the number of patients, sample weight, purification methods, PCR types, mutation points, and reference standards. The included studies showed no risk of publication bias.

CONCLUSION

PCR-based tests on stool samples have high diagnostic accuracy for detecting H. pylori clarithromycin resistance.

Mutant selection window of clarithromycin for clinical isolates of Helicobacter pylori

Background

Clarithromycin-resistance is becoming a global health concern in the treatment of Helicobacter pylori (H. pylori). The mutant prevention concentration (MPC) represent the propensities of antimicrobial agents to select resistant mutants. The concentration range between the minimum inhibitory concentration (MIC) and the MPC is defined as mutant selection window (MSW). In this study, we aimed to determine the cause of increasing clarithromycin resistance by investigating the MSW for clinical isolates of H. pylori.

Results

A retrospective subgroup, which included 68 clarithromycin-sensitive H. pylori strains, was selected from a double-blind trial. The MICs and MPCs were determined using agar plate assays. Genotypic tests were performed using Sanger sequencing. All isolates were wild-type, and 33.82% (23/68) had a 0.016 mg/L MIC, 45.59% (31/68) had a 0.031 mg/L MIC, 16.18% (11/68) had a 0.062 ≤ MIC ≤ 0.125 mg/L, and 4.41% (3/68) had a 0.25 mg/L MIC. The MPC_50/90 (mg/L) of the isolates were: 0.062/0.125, 0.125/0.5, 0.25/0.25 and 1/2, respectively. The MPCs showed a moderate correlation with the MICs (r_s = 0.65, P < 0.0001). Using published data and MPC₉₀, we calculated the time inside the MSW (T_MSW) for low- and high-dose (200 or 500 mg bid) clarithromycin that were 6 and 0 h, 24 and 4 h, 15 and 2 h, 5 and 17 h for the strains with MICs (mg/L) of 0.016, 0.031, 0.062–0.125, and 0.25, respectively.

Conclusions

This study showed that in the clarithromycin-sensitive clinical isolates of H. pylori, low-dose clarithromycin may lead to decreased drug sensitivity or even clarithromycin resistance; strains with a 0.25 mg/L MIC display a high risk of treatment failure.

Evaluation of a Novel Stool Antigen Rapid Test Kit for Detection of Helicobacter pylori Infection

The Quick Chaser H. pylori (QCP), which is a novel antigen detection kit for Helicobacter pylori, was developed recently. The previous examination kits targeted the catalase of H. pylori; however, this new test kit, to the best of our knowledge, is the first kit to target the flagellar protein of H. pylori The present study aimed to evaluate the efficacy of QCP compared with that of the already commercially available rapid test kit Testmate Rapid Pylori Antigen (TRP). TRP and QCP were utilized in 71 participants. The positive and negative concordance ratios of QCP to TRP were 100% (57/57) and 92.9% (13/14), respectively. Sensitivity based on the rapid urease test and culture test was 92.3%. Results of the dilution sensitivity test showed that QCP was eight times more sensitive to an H. pylori standard strain and the clarithromycin (CAM)-resistant clinical isolate and four times more sensitive to a CAM-susceptible clinical isolate than TRP. For the cross-reactivity test, 27 strains that exist in human feces, such as the Helicobacter genus, Bifidobacterium genus, Lactobacillus genus, and other resident bacteria, were selected. The results obtained using QCP were all negative, and no cross-reaction was observed. In conclusion, compared with TRP, QCP can detect H. pylori using clinical specimens with high sensitivity, regardless of CAM susceptibility and tolerance. No cross-reactivity was observed with other intestinal bacteria in humans. The kit is considered extremely useful in clinical settings.

Protection Against Helicobacter pylori Infection in BALB/c Mouse Model by Oral Administration of Multivalent Epitope-Based Vaccine of Cholera Toxin B Subunit-HUUC

Vaccination is an increasingly important alternative approach to control Helicobacter pylori infection, since H. pylori resistance to previously efficacious antibiotic regimens is increased, and H. pylori eradication treatment for upper gastrointestinal diseases is becoming less successful. Fortunately, an efficient oral monovalent H. pylori vaccine has been developed. However, compared with monovalent vaccines, multivalent vaccines have the potential to induce more effective and comprehensive protection against H. pylori infection. In this study, we designed and produced a multivalent epitope-based vaccine cholera toxin B subunit (CTB)-HUUC with the intramucosal adjuvant CTB and tandem copies of B-cell epitopes (HpaA132-141, UreA183-203, and UreB321-339) and T-cell epitopes (HpaA88-100, UreA27-53, UreB229-251, UreB317-329, UreB373-385, UreB438-452, UreB546-561, CagA149-164, and CagA196-217) from H. pylori adhesion A subunit (HpaA), urease A subunit (UreA), urease B subunit (UreB), and cytotoxin-associated antigen (CagA). Serum IgG, stomach, and intestine mucosal sIgA from mice after CTB-HUUC vaccination neutralized H. pylori urease activity in vitro. CTB-HUUC vaccination promoted H. pylori-specific lymphocyte responses and a mixed CD4⁺ T cell immune response as indicated by IFN-γ, interleukin-4, and interleukin-17 production in mice. Both oral prophylactic and therapeutic CTB-HUUC vaccinations reduced gastric urease activity and H. pylori infection and protected stomachs in mice. Taken together, CTB-HUUC is a promising potent and safe multivalent vaccine in controlling H. pylori infection in BALB/c mouse model.