Detection of Clarithromycin-Resistant
            <i>Helicobacter pylori</i>
            in Stool Samples

Fontana, Carla; Favaro, Marco; Pietroiusti, Antonio; Pistoia, Enrico Salvatore; Galante, Alberto; Favalli, Cartesio

doi:10.1128/jcm.41.8.3636-3640.2003

Cited by 42 publications

(26 citation statements)

References 23 publications

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“…This finding is in contrast to the findings of Fontana et al (4), who performed clarithromycin susceptibility testing with stool specimens by seminested PCR and restriction fragment length polymorphism analysis. In that study, only 2 of 125 H. pylori-positive patients (1.6%) were shown to be infected by a clarithromycin-resistant strain, and in both cases a T2717C mutation was detected.…”

Section: Discussioncontrasting

confidence: 55%

Novel Real-Time PCR Assay for Detection of Helicobacter pylori Infection and Simultaneous Clarithromycin Susceptibility Testing of Stool and Biopsy Specimens

Schabereiter-Gurtner

Hirschl

Dragosics³

et al. 2004

J Clin Microbiol

178

139

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A biprobe real-time PCR protocol, followed by hybridization melting point analysis, to detect point mutations in the 23S rRNA gene of Helicobacter pylori associated with clarithromycin resistance was established and evaluated in a clinical study. Of 92 patients who underwent endoscopy, 45 were found to be H. pylori infected and invariably were also culture positive. Of the 45 isolates, 11 were shown to be resistant to clarithromycin by E-test. With respect to the detection of H. pylori infection, PCR showed sensitivities of 100% in biopsies and 98% in stool specimens and a specificity of 98% in both biopsy and stool samples. All clarithromycin-sensitive cases were identified as such by PCR in both biopsy and stool samples. Of the cases with a resistant strain, eight were identified as such in stool DNA and nine were identified in biopsy DNA. Failure of PCR to detect the resistant genotype in the biopsy DNA, stool DNA, or both (one case) was associated with mixed populations. In these cases, patients had not been treated for H. pylori infection before, and the sensitive population showed to be present in considerably higher numbers than the resistant population. In five of six cases in which infection with a resistant genotype only was identified by PCR, the patients had received clarithromycin-based eradication therapy in the past. Thus, the assay presented provides a highly accurate noninvasive method to detect H. pylori infection in stool and at the same time allows for culture-independent clarithromycin susceptibility testing.Helicobacter pylori is a gram-negative bacterium associated with different digestive diseases, such as gastritis, peptic ulcer, mucosa-associated lymphoid tissue lymphoma, and gastric cancer (3). At present, several diagnostic assays for H. pylori detection are available (23). Invasive methods requiring gastric endoscopy include rapid urease testing, culture, histology, and molecular diagnostics. Noninvasive approaches include fecal antigen detection, serologic testing, and urea breath testing. During recent years, noninvasive methods gained in importance; however, no information on resistance against antibiotics can yet be obtained with these tests. Clarithromycin is an integral part of first-line therapies to treat H. pylori infection. As demonstrated by a meta-analysis of published data, susceptibility or resistance to clarithromycin result in eradication rates of 81 to 95% and 0 to 48%, respectively (8). Since clarithromycin is a widely used antimicrobial drug, the prevalence of clarithromycin-resistant H. pylori strains is increasing continuously.Resistance of H. pylori to clarithromycin is mainly due to an adenine-to-guanine transition at positions 2142 and 2143 and to an adenine-to-cytosine transversion at position 2142, which are included in the peptidyltransferase loop of the 23S rRNA (24). Recently, several PCR based methods, such as PCR-restriction fragment length polymorphism (17), PCR-DNA-enzyme immunoassay (13), reverse hybridization line probe assay (22), and real-time PCR...

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Section: Discussioncontrasting

confidence: 55%

Novel Real-Time PCR Assay for Detection of Helicobacter pylori Infection and Simultaneous Clarithromycin Susceptibility Testing of Stool and Biopsy Specimens

Schabereiter-Gurtner

Hirschl

Dragosics³

et al. 2004

J Clin Microbiol

178

139

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“…The first one is related to the existence of mechanisms of resistance apart from those associated with the three point mutations assessed in this study (15,40,41). In fact, the 86.7% concordance obtained between PNA-FISH and the Etest is in agreement with what has been observed in other studies, where the three point mutations assessed here were present in 84% to 90% of clarithromycin-resistant H. pylori strains (7,14).…”

Section: Discussionmentioning

confidence: 99%

Validation of a Fluorescence In Situ Hybridization Method Using Peptide Nucleic Acid Probes for Detection of Helicobacter pylori Clarithromycin Resistance in Gastric Biopsy Specimens

et al. 2013

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h Here, we evaluated a previously established peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) method as a new diagnostic test for Helicobacter pylori clarithromycin resistance detection in paraffin-embedded gastric biopsy specimens. Both a retrospective study and a prospective cohort study were conducted to evaluate the specificity and sensitivity of a PNA-FISH method to determine H. pylori clarithromycin resistance. In the retrospective study (n ‫؍‬ 30 patients), full agreement between PNA-FISH and PCR-sequencing was observed. Compared to the reference method (culture followed by Etest), the specificity and sensitivity of PNA-FISH were 90.9% (95% confidence interval [CI], 57.1% to 99.5%) and 84.2% (95% CI, 59.5% to 95.8%), respectively. In the prospective cohort (n ‫؍‬ 93 patients), 21 cases were positive by culture. For the patients harboring clarithromycin-resistant H. pylori, the method showed sensitivity of 80.0% (95% CI, 29.9% to 98.9%) and specificity of 93.8% (95% CI, 67.7% to 99.7%). These values likely represent underestimations, as some of the discrepant results corresponded to patients infected by more than one strain. PNA-FISH appears to be a simple, quick, and accurate method for detecting H. pylori clarithromycin resistance in paraffin-embedded biopsy specimens. It is also the only one of the methods assessed here that allows direct and specific visualization of this microorganism within the biopsy specimens, a characteristic that allowed the observation that cells of different H. pylori strains can subsist in very close proximity in the stomach.

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“…Clarithromycin resistance is due to point mutations on 23S rRNA, where they change the spatial confi guration of the ribosome [25] . As the point mutations are known, clarithromycin resistance may be rapidly and accurately detected by PCR, and indeed a recent study has detected clarithromycin resistance in a stool sample, eliminating the need for an invasive test [26] . Primary resistance to clarithromycin is a strong predictive risk factor for treatment failure, with eradication of H. pylori falling from rates of over 90% with clarithromycin-sensitive strains to less than 1% with clarithromycin-resistant strains [27] .…”

Section: Antibiotic Resistancementioning

confidence: 99%

Effectiveness of Antiinfectives

McLoughlin

O’Moráin²

2005

Chemotherapy

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Background:Helicobacter pylori is one of the most common infections of mankind, with persistent colonization causing significant morbidity and mortality. Treatment: First-line therapy, consisting of 7-day treatment with a proton pump inhibitor or ranitidine bismuth citrate, amoxicillin and clarithromycin, with second-line therapy, consisting of a proton pump inhibitor, bismuth, metronidazole, and tetracycline, in the case of failure, is chosen as the most cost-effective method of H. pylori eradication. Conclusion: The effectiveness of these antiinfectives is limited by lack of compliance with treatment regimens, and increasing antibiotic resistance.

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Detection of Clarithromycin-Resistant Helicobacter pylori in Stool Samples

Cited by 42 publications

References 23 publications

Novel Real-Time PCR Assay for Detection of Helicobacter pylori Infection and Simultaneous Clarithromycin Susceptibility Testing of Stool and Biopsy Specimens

Novel Real-Time PCR Assay for Detection of Helicobacter pylori Infection and Simultaneous Clarithromycin Susceptibility Testing of Stool and Biopsy Specimens

Validation of a Fluorescence In Situ Hybridization Method Using Peptide Nucleic Acid Probes for Detection of Helicobacter pylori Clarithromycin Resistance in Gastric Biopsy Specimens

Effectiveness of Antiinfectives

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