Comparison of Helicobacter pylori eradication rates between 7 and 14 days of tailored therapy according to clarithromycin resistance test: A randomized, multicenter, non-inferiority study.

BACKGROUND: Recently, a simple tailored therapy based on clarithromycin resistance has been implemented as Helicobacter pylori (H. pylori) eradication therapy. Nonetheless, despite the tailored therapy and frequent adverse events, studies on treatment period are lacking. This study aimed to compare the H. pylori eradication rates of 7-day and 14-day tailored therapy regimens according to clarithromycin resistance. MATERIALS AND METHODS: This multicenter, prospective, randomized, noninferiority trial enrolled H. pylori-positive patients who were randomly assigned to 7-day and 14-day regimen groups, depending on the presence or absence of clarithromycin resistance by 23S rRNA gene point mutations. Standard triple therapy (STT) (20 mg rabeprazole, 1 g amoxicillin, and 500 mg clarithromycin twice daily) or bismuth quadruple therapy (BQT) (20 mg rabeprazole twice daily, 500 mg metronidazole thrice daily, 120 mg bismuth four times daily, and 500 mg tetracycline four times daily) was assigned by clarithromycin resistance. Eradication rates and adverse events were evaluated. RESULTS: A total of 314 and 278 patients were included in the intention-to-treat (ITT) and per-protocol (PP) analyses, respectively; however, 31 patients were lost to follow-up, whereas five patients violated the protocol. Both the 7-day and 14-day regimens showed similar eradication rates in the ITT (7-day vs. 14-day: 78.3% vs. 78.3%, p > 0.99) and PP (87.9% vs. 89.1%, p = 0.851) analyses. Non-inferiority was confirmed (p < 0.025). A subgroup analysis according to clarithromycin resistance (clarithromycin resistance rate: 28.7%) revealed no significant difference in eradication rates between the 7-day and 14-day STT (90.0% vs. 90.1%, p > 0.99) and BQT (82.5% vs. 86.5%, p = 0.757). Furthermore, adverse events did not significantly differ between the two groups. CONCLUSIONS: The 7-day triple and quadruple therapy according to clarithromycin resistance showed similar eradication rates, as compared to the 14-day therapy.

RIDA®GENE Helicobacter pylori PCR on the ELITe InGenius System.

PCR detection of Helicobacter pylori infection in gastric biopsies allows the detection of this bacterium and the mutations associated with macrolide resistance. The aim of this study was to evaluate the performance of RIDA®GENE H. pylori PCR (r-Biopharm) on the ELITe InGenius System (Elitech). Two hundred gastric biopsies were obtained. These biopsies were ground in nutrient broth. Two hundred microliters of this suspension was treated with proteinase K, and then, 200 µL was transferred to an ELITe InGenius sample tube and tested using RIDA®GENE H. pylori PCR reagents. In-house H. pylori PCR was used as a reference. The sensitivity of RIDA®GENE H. pylori PCR with ELITe InGenius was 100%, the specificity was 98% (95% confidence interval (CI), 95.3-100%), the PPV was 98% (95% CI, 95.3-100%), and the NPV was 100% for the detection of H. pylori. All of these parameters were 100% for the categorization of macrolide resistance. The adaptation of RIDA®GENE H. pylori PCR reagents on the ELITe InGenius System was successful. This PCR is easy to use on this system.

Individualized diagnosis and eradication therapy for Helicobacter pylori infection based on gene detection of clarithromycin resistance in stool specimens: A systematic review and meta-analysis.

BACKGROUND: Empiric therapy for Helicobacter pylori infection results in significantly increased antibiotic resistance and decreased eradication efficacy. The genotypic testing of clarithromycin resistance from stool specimens is a promising method for individualized diagnosis and treatment. This study aimed to determine the status of research and application on this method through a systematic review and meta-analysis. METHODS: PubMed, Embase, MEDLINE, and WAN FANG database were searched for relevant literature. The quality of included diagnostic articles was evaluated using the quality Assessment of Diagnostic Accuracy Studies-2 tool. A bivariate random-effect model was conducted to calculate the diagnostic accuracy of genotypic testing of clarithromycin resistance. RESULTS: A total of 16 diagnostic-related were included and analyzed after exclusions. The pooled sensitivity and specificity of diagnostic meta-analysis were 0.93 (95% confidence interval [CI]: 0.90-0.96) and 0.98 (95% CI: 0.93-1.00), respectively. The area under the curve (AUC) of the summary receiver operating characteristic was 0.97 (95% CI: 0.95-0.98). The genotypic testing in stool samples had heterogeneous sensitivity (Q = 37.82, p < .01, I2  = 37.82) and specificity (Q = 60.34, p < .01, I2  = 93.72) in detecting clarithromycin resistance. Purification method, stool sample weight, real-time PCR, and antimicrobial susceptibility testing as reference accounted for the heterogeneity of pooled sensitivity, while patient age, purification method, stool sample weight, and real-time PCR for the heterogeneity of pooled specificity. CONCLUSION: The genotypic testing of clarithromycin resistance from stool specimens is an accurate, convenient, noninvasive, and rapid detection technology, providing a definitive diagnosis of clarithromycin resistance and guiding the rational antibiotic selection.

Cases of severe Mycobacterium avium lung disease occurred in a married couple caused by identical strain.

Bacteria of the Mycobacterium avium complex, which are environmental organisms found in soil and water, have been found to cause human lung diseases. Although infection is reported to occur in cohabiting patients, the incidence of infection from the single clone remains rarely documented. Herein, we report a case of M. avium lung disease caused by specimens with the same clone strains in a married couple. The wife, a 67-year-old female, had severe M. avium lung disease despite receiving multidrug chemotherapy for eleven years. The husband, a 68-year-old male, died of acute lung injury complicated by M. avium pleurisy. The result of the variable-number tandem-repeat analysis of isolates from serial sputum specimens of both patients indicated that the severe M. avium lung disease in a married couple was caused by the isolates with identical pattern. This case were considered to have acquired clarithromycin resistance during each clinical course, revealing the possibility of infection with a strain that may induce severe pulmonary condition.

Evaluation of a Molecular Mosprie Assay for Detection of Helicobacter pylori and Resistance to Clarithromycin and Levofloxacin.

BACKGROUND: Helicobacter pylori eradication regimens should be guided by antimicrobial susceptibility testing. The objective of this study was to evaluate the molecular-based Mosprie assay for detecting H. pylori resistance to clarithromycin and levofloxacin using gastric biopsies. METHODS: A total of 185 culture-positive frozen gastric biopsies were included for Mosprie assay and also for 23S rRNA and gyrA gene sequencing. The susceptibility results by the Mosprie assay were compared with the E-test results retrospectively retrieved. The discordant results were analyzed by sequencing of the 23S rRNA and gyrA genes. RESULTS: Susceptibility concordance between the Mosprie assay and E-test for clarithromycin and levofloxacin was 97.30% (180/185) and 88.11% (163/185), respectively. The full agreement between clarithromycin genotypes by Mosprie assay and the 23S rRNA sequencing results was observed in the 5 samples with discordant Mosprie assay and E-test results. However, for levofloxacin, of the 16 discordant samples with resistant phenotype but a susceptible genotype by Mosprie assay, 6 were found to have levofloxacin resistance-related gyrA gene mutations. CONCLUSIONS: The rapid and reliable Mosprie assay can be recommended for H. pylori susceptibility testing of clarithromycin and levofloxacin on gastric biopsies. Future technical improvements are needed in detecting levofloxacin resistance-associated gene mutations.

RELATIONSHIP OF HELICOBACTER PYLORI CAGA AND VACA STATUS TO MORPHOLOGICAL CHANGES OF GASTRIC MUCOSA AND PRIMARY CLARITHROMYCIN RESISTANCE RATE IN PATIENTS WITH CHRONIC GASTRITIS: A CROSS-SECTIONAL STUDY.

OBJECTIVE: The aim: To investigate the relation of H. pylori CagA and VacA status to morphological changes of gastric mucosa and primary clarithromycin resistance rate in patients with chronic gastritis. PATIENTS AND METHODS: Materials and methods: A cross-sectional study was conducted between May 2021 and January 2023, involving 64 patients with H. pylori-associated chronic gastritis. The patients were assigned to two groups according to the H. pylori virulence factors (CagA and VacA) status. The grades of inflammation, activity, atrophy, and metaplasia were determined according to the Houston-updated Sydney system. The identification of H. pylori genetic markers of antibiotic resistance and pathogenicity was performed by the polymerase chain reaction using paraffin stomach biopsies. RESULTS: Results: Patients with CagA- and VacA-positive H. pylori strains had significantly higher grades of inflammation both in the antrum and in the corpus of the stomach, activity of gastritis in the antrum, higher incidence and grade of atrophy in the antrum. Primary resistance to clarithromycin was significantly more prevalent in patients with CagA- and VacA-negative H. pylori strains (58.3% vs. 11.5%, p=0.002). CONCLUSION: Conclusions: Positive CagA and VacA status is related to more severe histopathological changes of gastric mucosa. In contrast, the rate of primary clarithromycin resistance is higher in patients CagA- and VacA-negative H. pylori strains.

Detection of Mixed Populations of Clarithromycin-Susceptible and -Resistant Mycobacterium abscessus Strains.

Clarithromycin resistance in Mycobacterium abscessus subsp. abscessus, massiliense, and bolletii occurs through induction of erm(41) or mutations in rrl (23S rRNA) genes. Phenotypic detection of clarithromycin resistance is hindered by the need for extended incubation as well as co-occurrence of mixed populations of M. abscessus with different susceptibility profiles. We developed a quantitative EvaGreen-based droplet digital PCR (ddPCR) scheme for rapid detection of full-length or truncated erm(41) and a probe based ddPCR screening assay for assessment of 23S rRNA rrl mutational resistance. We tested 100 M. abscessus strains, synthetic mixes with different susceptibility profiles, and 13 positive MGIT samples. Truncated and full-length erm(41) genes were detected in 27/100 and 73/100 strains and 4/13 and 9/13 MGIT samples, respectively yielding a sensitivity and specificity of 100%. Clarithromycin resistance mutations in rrl were detected in 26/100 isolates, i.e., A2058G (18/100), A2058C (7/100), and A2059G (1/100), and in 3/13 MGIT samples, i.e., A2058G (2/13) and A2059G (1/13). A screening assay of rrl ddPCR (A2058A/A2058G probes) showed 100% sensitivity in detecting the wild type or A2058G mutation as well as identifying samples requiring further testing. Upon inclusion of additional ddPCR assays, we were able to detect A2058C and A2059G clarithromycin resistance-conferring mutations in the rrl gene. Our ddPCR scheme can differentiate between full-length and truncated erm(41) and identify clarithromycin resistance-conferring mutations in the rrl gene from clinical isolates and positive MGIT samples as well as deconvolute and quantitate mixed populations of M. abscessus with different clarithromycin resistance traits.

Automation of RIDA®GENE Helicobacter pylori PCR on the BD MAX™ System.

PCR detection of Helicobacter pylori infection in gastric biopsies allows the detection of this bacterium and the mutations associated with macrolide resistance. The aim of this study was to evaluate the performance of RIDA®GENE H. pylori PCR (r-Biopharm) on a BD MAX™ System (Becton Dickinson). Two hundred ten gastric biopsies obtained were included. These biopsies were ground in nutrient broth. Two hundred microliters of this suspension was treated with proteinase K; 200 µL was transferred to a BD MAX™ sample tube then tested using RIDA®GENE H. pylori PCR reagents. In-house H. pylori PCR was used as a reference. The sensitivity of RIDA®GENE H. pylori PCR with BD MAX™ was 100%, the specificity was 99.08% (95% confidence interval (CI), 97.21-100%), the PPV was 99.02% (95% CI, 97.09-100%), and the NPV was 100% for the detection of H. pylori. The sensitivity was 97.14% (95% CI, 93.87-100%), the specificity was 100%, the PPV was 100%, and the NPV was 98.48% (95% CI, 96.08-100%) for categorization of macrolides resistance. The adaptation of RIDA®GENE H. pylori PCR on the BD MAX™ System is of considerable interest for microbiologists who seek to establish this assay in their laboratories.

Helicobacter pylori 23S rRNA gene A2142G, A2143G, T2182C, and C2195T mutations associated with clarithromycin resistance detected in Sudanese patients.

BACKGROUND: Clarithromycin resistant Helicobacter pylori (H. pylori) strains represent a worldwide health problem. These stains are usually carrying mutations within the 23S rRNA gene associated with clarithromycin resistance. This study aimed to detect H. pylori and clarithromycin resistant associated mutations from Sudanese patients with gastritis symptoms. MATERIALS AND METHODS: Two hundred and eighty-eight gastric biopsies were collected using gastrointestinal endoscopy from patients with gastritis symptoms in different hospitals in Khartoum state. H. pylori was detected by PCR using primer targeting 16S rRNA. Then allele-specific PCR and DNA sequencing were used to screen for the presence of A2142G and A2143G point mutations. RESULTS: Out of 288 samples, H. pylori was detected in 88 (~ 30.6%) samples by 16 s RNA. Allele-specific PCR detected the variant A2142G in 9/53 (~ 17%) sample, while A2143G mutation was not found in any sample. The DNA sequencing revealed the presence of mutations associated with clarithromycin-resistance in 36% (9/25) of samples; the A2142G was present in one sample, A2143G in 5 samples and T2182C in 4 samples. Additionally, another point mutation (C2195T) was detected in 3 samples. There was no association of 23S rRNA gene point mutations with gender, age group, and patients' geographical distribution. CONCLUSION: This study revealed a high frequency (36%) of mutations associated with clarithromycin resistance using DNA sequencing of the 23S rRNA gene's V domain. This information should be taken into consideration to avoid eradication therapy failing.

Molecular testing for H. pylori clarithromycin and quinolone resistance: a prospective Chinese study.

In China, there is a high prevalence of antibiotic-resistant Helicobacter pylori infections in the population. The aim of the study was to assess a new ARMS-PCR test for detection of H. pylori clarithromycin resistance (CR) and quinolone resistance (QR) mutations and evaluate the spectrum of antibiotic resistance in patients from three Chinese provinces. Sanger sequencing and multiplex ARMS-PCR were used to detect H. pylori CR and QR bacteria in gastric biopsy samples. Among the 1,182 patients enrolled with gastritis, 643 (54.4%) were positive for H. pylori. Of these, 371 (57.7%) had antibiotic-resistant strains, comprising 236 (63.6%) with a single drug antibiotic-resistant strain and 135 (36.4%) with multiple drug-resistant strains. Following Sanger sequencing analysis of 23S rRNA and gyrA gene for mutations (antibiotic resistance markers), rates of CR, QR, and multidrug resistance (CR and QR) were 19.9, 12.0, and 25.8%, respectively. The 23S rRNA CR mutation A2143G (286, 96.9%) and the gyrA QR mutations C261A (85, 31.5%) and G271A (71, 26.3%) were common. Benchmarking against Sanger sequencing results, multiplex ARMS-PCR test had a high diagnostic sensitivity and specificity for detection of CR (96 and 93%), QR (95 and 92%) and multidrug resistance (95 and 95%). Based on our findings, the high incidence of single and multiple antibiotic resistance requires the routine checking of antibiotic resistance in all patients with suspected H. pylori infections. Multiplex ARMS-PCR is a simple and rapid test that can be now used for more efficient treatment of H. pylori infections and reduces the misuse of antibiotics.

Adaptation of an in-house PCR for the detection of Helicobacter pylori and the mutations associated with macrolide resistance into ready-to-use PCR microwell strips.

BACKGROUND AND OBJECTIVES: The present study describes the successful adaptation of an in-house Polymerase Chain Reaction (PCR) for Helicobacter pylori detection coupled with the main mutations associated with resistance to clarithromycin in ready-to-use PCR microwell strips. MATERIALS AND METHODS: These microwell strips can be used on LightCycler® 480, and are delivered with nine microliters of the reaction mixture dispensed into 8-well microwell strips. An extraction control PCR targeting the ß-globin household gene is amplified in the same run as H pylori detection. RESULTS AND CONCLUSION: These microwell strips can be stored at -20°C for 1 year and left at room temperature and in the light for up to 4 h with no impact on the PCR results. Microwell strips can also undergo a thaw and refreeze cycle without impacting the PCR results. These PCR microwell strips are available for purchase from Eurogentec.

Clarithromycin versus furazolidone for naïve Helicobacter pylori infected patients in a high clarithromycin resistance area.

BACKGROUND AND AIM: The increase in antibiotic resistance makes the eradication of Helicobacter pylori more difficult. Considering the limitations of the application of susceptibility-guided therapy, it is important to find an effective empirical regimen. The aim of the study is to compare the efficacy, safety, and cost-effectiveness of clarithromycin-based bismuth-containing quadruple therapy (C-BQT) and furazolidone-based bismuth-containing quadruple therapy (F-BQT) in naïve H. pylori positive patients. METHODS: This was an open-label, randomized controlled, crossover trial. The trial comprised two phases. In C-F group, patients received C-BQT in the first phase; those who were still positive for H. pylori infection after the first phase entered the second phase to receive F-BQT as rescue treatment. In F-C group, patients were treated with F-BQT firstly and rescued with C-BQT. RESULTS: As first-line treatments, the eradication rates of C-BQT and F-BQT were 89.7% (157/175) and 92.0% (161/175) (P = 0.458) in intention-to-treat analysis and 93.4% (156/167) and 95.8% (161/168) (P = 0.327) in per-protocol analysis, respectively. The cumulative eradication rates of the C-F group and the F-C group were both 94.3% in intention-to-treat analysis (P = 1.000). Cost-effectiveness indexes of F-BQT and C-BQT were 0.54 and 1.24 in first-line treatments. Frequencies of adverse events in F-BQT and C-BQT had no differences (36.0% in C-BQT vs 32.6% in F-BQT, P = 0.499). CONCLUSIONS: Furazolidone-based bismuth-containing quadruple therapy should be preferred for its excellent cost-effectiveness and acceptable safety.

Helicobacter pylori eradication therapy outcome according to clarithromycin susceptibility testing in Japan.

BACKGROUND: Helicobacter pylori (Hp) infection increases the risk of gastric cancer. Therefore, eradication is a global goal, which requires continuous monitoring of therapeutic regimens and effectiveness. Clarithromycin resistance is an important contributor to eradication failure, and metronidazole is recommended as second-line treatment in such cases. Here, we retrospectively evaluated the clarithromycin and metronidazole resistance rates and treatment effectiveness in patients with Hp using tailored therapies according to clarithromycin susceptibility testing. METHODS: Data on drug susceptibility were obtained for 5249 Japanese Hp patients between July 2005 and August 2018. Clarithromycin/metronidazole resistance rates were analyzed according to year, gender, and age with Fisher's exact test. The relationship between clarithromycin resistance and Hp therapy outcomes was assessed for 1300 patients. Treatment regimens included a clarithromycin- or metronidazole-containing 7-day triple therapy with one of several proton pump inhibitors and vonoprazan. RESULTS: Clarithromycin resistance increased annually and was higher in women and younger patients (<30 years). Rates of metronidazole resistance were stable but decreased with age. Hp treatment regimens using PPIs had eradication rates of 88% and 45% among clarithromycin-sensitive and clarithromycin-resistant cases, respectively, while regimens including vonoprazan had eradication rates of around 90% regardless of clarithromycin susceptibility. In particular, triple therapy with vonoprazan, amoxicillin, and metronidazole achieved 98% eradication. CONCLUSION: Clarithromycin-containing triple therapy even using vonoprazan did not achieve satisfactory eradication rates even in the clarithromycin-sensitive group. To avoid antibiotic misuse in population with low metronidazole resistance, 7-day vonoprazan, amoxicillin, and metronidazole triple therapy might be a strong candidate as a first-line eradication therapy.

Helicobacter pylori heteroresistance to clarithromycin in adults-New data by in situ detection and improved concept.

BACKGROUND: Clarithromycin (Cla) heteroresistance of Helicobacter pylori (H pylori) infections is commonly assessed by comparing the resistance status of antrum and corpus biopsy samples and by demonstrating the discrepancy between them (interniche heteroresistance). However, fluorescence in situ hybridization (FISH) technique is capable of showing the synchronous presence of susceptible and resistant bacteria (intraniche heteroresistance), enabling the detection of heteroresistant H pylori populations within one biopsy sample. MATERIALS AND METHODS: Antrum and corpus biopsy specimens of 305 H pylori-infected patients were investigated with an rRNA-targeted Cla-resistance FISH test. Anamnestic data were collected from the institutional electronic register. Prevalence rates of susceptible, homo- and heteroresistant cases were correlated with the anamnestic and clinicopathological data. RESULTS: Overall Cla-resistance rate was 23.9% (73 cases), consisting of 35 (11.5%) homoresistant and 38 (12.5%) heteroresistant cases. Thirty-five patients had at least one biopsy site where susceptible and resistant bacteria were present simultaneously. From this subset, 20 cases demonstrated intraniche heteroresistance on both sites. Prior Cla-based eradication attempts were more frequent in homoresistant than in susceptible and heteroresistant cases (P < .001, P < .001, respectively). Cla-containing therapy eradicated heteroresistant infections at a significantly lower rate in comparison with susceptible cases (P = .0112), but more effectively than homoresistants (P = .0393). CONCLUSIONS: The most frequent type of Cla-heteroresistance is the coexistence of susceptible and resistant H pylori bacteria in the same location (intraniche heteroresistance). A previous Cla-based eradication attempt predisposes patients to homoresistant infection. Heteroresistance is characterized by a non-eradication-related background and intermediate characteristics in many respects when compared to susceptible and homoresistant cases.

CRHP Finder, a webtool for the detection of clarithromycin resistance in Helicobacter pylori from whole-genome sequencing data.

BACKGROUND: Resistance to clarithromycin in Helicobacter pylori (H pylori) is mediated by mutations in the domain V of the 23S rRNA gene (A2142G, A2143G, A2142C). Other polymorphisms in the 23S rRNA gene have been reported to cause low-level clarithromycin resistance but their importance is still under debate. In this study, we aimed to develop and evaluate the CRHP Finder webtool for detection of the most common mutations mediating clarithromycin resistance from whole-genome sequencing (WGS) data. Moreover, we included an analysis of 23 H pylori strains from Danish patients between January 2017 and September 2019 in Copenhagen, Denmark. MATERIALS AND METHODS: The CRHP Finder detects the fraction of each of the four nucleotides in nucleotide positions 2142, 2143, 2182, 2244 and 2712 of the 23S rRNA gene in H pylori (E coli numbering) by aligning raw sequencing reads (fastq format) with k-mer alignment (KMA). The nucleotide distribution in each position is compared to previously described point mutations mediating clarithromycin resistance in H pylori, and a genotypic prediction of the clarithromycin resistance phenotype is presented as output. For validation of the CRHP webtool, 137 fastq paired-end sequencing datasets originating from a well-characterized strain collection of H pylori were analyzed. RESULTS: The CRHP Finder correctly identified all resistance mutations reported in the sequencing data of 137 H pylori strains. In the 23 Danish H pylori strains, CRHP Finder detected A2143G (13%) in all resistant strains, and T2182C (13%) and C2244T (4,3%) nucleotide exchanges in only susceptible strains. CONCLUSION: In this study, we present the validation of the first webtool for H pylori resistance prediction based on the detection of 23S rRNA mutations (A2142C, A2142G, A2143G, T2182C, C2244T, T2712C) from WGS data of H pylori.

The outward shift of clarithromycin binding to the ribosome in mutant Helicobacter pylori strains.

OBJECTIVES: Disruption of protein synthesis, by drug-mediated restriction of the ribosomal nascent peptide exit tunnel (NPET), may inhibit bacterial growth. Here, we have studied the secondary and tertiary structures of domain V of the 23S rRNA in the wild-type and mutant (resistant) H. pylori strains and their mechanisms of interaction with clarithromycin (CLA). METHODS: H pylori strains, isolated from cultured gastric biopsies, underwent CLA susceptibility testing by E test, followed by PCR amplification and sequencing of domain V of 23S rRNA. The homology model of this domain in H pylori, in complex with L4 and L22 accessory proteins, was determined based on the E. coli ribosome 3D structure. The interactions between CLA and 23S rRNA complex were determined by molecular docking studies. RESULTS: Of the 70 H pylori strains, isolated from 200 dyspeptic patients, 11 (16%) were CLA-resistant. DNA sequencing identified categories with no (A), A2142G (B), and A2143G (C) mutations. Docking studies of our homology model of 23S rRNA complex with CLA showed deviated positions for categories B and C, in reference to category A, with 12.19 Å and 7.92 Å RMSD values, respectively. In both mutant categories, CLA lost its interactions at positions 2142 and 2587 and gained two new bonds with the L4 accessory protein. CONCLUSION: Our data suggest that, in mutant H pylori strains, once the nucleotides at positions 2142 and 2587 are detached from the drug, CLA interacts with and is peeled back by the L4 accessory protein, removing the drug-imposed spatial restriction of the NPET.

Assessment of a novel method to detect clarithromycin-resistant Helicobacter pylori using a stool antigen test reagent.

BACKGROUND: The resistance rate of Helicobacter pylori to clarithromycin (CAM) is high among infected children in Japan. Therefore, a new method for detecting CAM-resistant H. pylori using a minimally invasive technique is strongly desired. We aimed to investigate the clinical usefulness of our newly developed nested polymerase chain reaction-quenching probe (Nested PCR-QP) method using stool specimens. METHODS: We first evaluated our method using a residual solution of the H. pylori stool antigen test for adolescents. Then, we evaluated our method using culture testing for adults. RESULTS: Among 57 middle school students with H. pylori, the Nested PCR-QP test results of 53 (90.3%) were able to be analyzed. A total of 28 students had CAM resistance mutations. We found a genetic mutation in 28 students and no mutation in 23 students, and these results were consistent with those of PCR-direct sequencing. In the 23 adults who were diagnosed with H. pylori infection using the rapid urease test and culture testing, we were able to use Nested PCR-QP for analyzing 21 adults who tested positive in the stool H. pylori antigen test. The results obtained for all 21 adults were consistent with those obtained via the drug susceptibility test. CONCLUSIONS: Our novel method could be useful for non-invasively detecting CAM resistance mutations in H. pylori. This may help select a drug to reduce eradication failure rates against H. pylori. Trial registration This study was registered with the University Hospital Medical Information Network Clinical Trials Registry (no. UMIN000030632, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000034977 ) on 29 December 2017.

Surveillance of the Antimicrobial Resistance Rates of Helicobacter pylori Ten Years Later in the Western Central Region, Colombia.

BACKGROUND: Helicobacter pylori is a bacterium associated with gastroduodenal disease and gastric cancer. Empirical therapy in the treatment of H. pylori infection increases the risk of apparition of antimicrobial drug resistance. In a previous report, in H. pylori clinical isolates, resistance rates to commonly used antimicrobial drugs were as follows: metronidazole 82%, clarithromycin 3.8%, and amoxicillin 1.9%. The aim was to establish the variation of resistance rates and the detection of H. pylori genetic mutations isolated from dyspeptic patients. METHODS: Antimicrobial susceptibility profiles were performed by the E-test method for metronidazole, clarithromycin, amoxicillin, and tetracycline in 61 clinical isolates. Sequencing was performed to detect mutations associated with resistance to clarithromycin. RESULTS: According to our results, resistance rates found in the 61 isolates were 78.60% for metronidazole and 8.20% for clarithromycin. None of the studied isolates had resistance to tetracycline and amoxicillin. Secondary resistance rates displayed an increase when compared to primary rates for metronidazole (87.50 vs. 77.35%) and for clarithromycin (25.66 vs. 5.66%). Of 5 isolates resistant to clarithromycin, 3 had the A2143G mutation. By comparing the results in this work with previous reports, antimicrobial drug resistance rates did not show major modifications for metronidazole, amoxicillin, and tetracycline during the last 10 years. For clarithromycin, the resistance rate showed a moderate increase; nevertheless, it remains low (<15%) and this change was not statistically significant. CONCLUSION: Together, all findings in this work indicate that these antimicrobial drugs can still be used as first line of defense on infected patients living in this region of the country.

Effect of Helicobacter pylori biofilm formation on susceptibility to amoxicillin, metronidazole and clarithromycin.

The human gastric pathogen Helicobacter pylori forms biofilms in vitro and in vivo. We previously demonstrated that H. pylori biofilm formation in vitro decreased its susceptibility to clarithromycin (CAM). The aim of this study was to evaluate the effects of biofilm formation on amoxicillin (AMPC) and metronidazole (MNZ) susceptibility. In addition, we assessed the influence of biofilms of CAM resistant H. pylori on CAM susceptibility. It was shown that high levels of efflux pump gene transcripts were detected in biofilm cells of all H. pylori strains used in this study. H. pylori biofilm biomass was significantly decreased compared to initial biomass after treatment with the minimum inhibitory concentration (MIC) of AMPC. Similarly, the biofilm biomass of H. pylori decreased after treatment with MIC of MNZ, although the difference was not statistically significant. However, minimum bactericidal concentrations (MBCs) of AMPC or MNZ to biofilm cells were higher than those of planktonic cells. The biofilm biomasses of all of the CAM resistant strains were significantly decreased compared to initial biomass after treatment with 2x MIC of CAM. However, the viability of the CAM treated biofilm cells with 2x MIC of CAM was not significantly reduced compared to initial cell numbers with the exception of one strain. The viability of biofilm cells of all strains was higher than that of planktonic cells after treatment with various concentrations of CAM. These results indicate that biofilm cells were more resistant to these antibiotics than planktonic cells and that the assessment of the ability to form biofilms in H. pylori is important for eradication of this microorganism.

Bismuth-containing quadruple therapy versus concomitant quadruple therapy as first-line treatment for Helicobacter Pylori infection in an area of high resistance to clarithromycin: A prospective, cross-sectional, comparative, open trial.

BACKGROUND: Concomitant quadruple (CQT) or bismuth-containing quadruple therapy (BQT) is recommended as first-line treatment for Helicobacter pylori infection depending on antibiotic resistance. AIM: To compare the efficacy, safety, and compliance of CQT and BQT as first-line therapy for H. pylori eradication in real clinical practice in an area of high resistance to clarithromycin. METHODS: A prospective, open, comparative cross-sectional study including dyspeptic patients >18 years with H. pylori infection and with no previous eradication treatment was performed. CQT (omeprazole 20 mg + clarithromycin 500 mg + amoxicillin 1 g + metronidazole 500 mg, all given twice daily, for 14 days) or BQT (omeprazole 20 mg twice daily + 3 capsules of Pylera® 4 times a day, for 10 days) was prescribed at the discretion of the prescribing physician. Eradication was tested by 13 C-urea breath test. Efficacy was assessed by intention-to-treat (ITT) and per-protocol (PP) analyses. RESULTS: One hundred and four consecutive patients were included (64.4% female, age 52.9 years). Fifty patients received CQT and 54 BQT. Eradication rate was similar with both therapies at the PP (CQT 97.9%, 95% CI: 93.9-100 vs BQT 96.2%, 95% CI: 90.9-100, P = 0.605) and ITT analyses (CQT 98.0%, 95% CI: 94-100 vs BQT 94.4%, 95% CI: 88.1-100, P = 0.346). The rate of adverse events was also similar with CQT (56%) and BQT (46.3%). One patient in each group discontinued the treatment due to significant adverse events. CONCLUSION: The use of CQT and BQT as first-line treatment against H. pylori is similarly effective and safe strategy in an area of high clarithromycin resistance.