Helicobacter pylori clarithromycin resistance assessment: are gastric antral biopsies sufficient?

Francesco, Vincenzo De; Giorgio, Floriana; Ierardi, Enzo; Hassan, Cesare; Zullo, Angelo

doi:10.4081/gi.2012.e2

Cited by 5 publications

(3 citation statements)

References 15 publications

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“…All ClaR samples were confirmed by Sanger sequencing. Both Sanger sequencing and 5’exonuclease allowed us to detect heteroresistance, i.e., the coexistence of resistant and susceptible bacterial strains in the same patient [ 12 ]. Sixteen (16) out of 93 H.pylori subjects were homoresistant to clarithromycin (17.2%).…”

Section: Resultsmentioning

confidence: 99%

Prevalence of clarithromycin resistance in Helicobacter pylori in Santiago, Chile, estimated by real-time PCR directly from gastric mucosa

et al. 2018

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BackgroundCurrent available treatments for Helicobacter pylori eradication are chosen according to local clarithromycin and metronidazole resistance prevalence. The aim of this study was to estimate, by means of molecular methods, both clarithromycin and metronidazole resistance in gastric mucosa from patients infected with H.pylori.MethodsA total of 191 DNA samples were analyzed. DNA was purified from gastric mucosa obtained from patients who underwent an upper gastrointestinal endoscopy at an university hospital from Santiago, Chile, between 2011 and 2014. H.pylori was detected by real-time PCR. A 5’exonuclease assay was developed to detect A2142G and A2143G mutations among H.pylori-positive samples. rdxA gene was sequenced in samples harboring A2142G and A2143G mutations in order to detect mutations that potentially confer dual clarithromycin and metronidazole resistance.ResultsNinety-three (93) out of 191 DNA samples obtained from gastric mucosa were H.pylori-positive (48.7%). Clarithromycin-resistance was detected in 29 samples (31.2% [95%CI 22.0–41.6%]). The sequencing of rdxA gene revealed that two samples harbored truncating mutations in rdxA, one sample had an in-frame deletion, and 11 had amino acid changes that likely cause metronidazole resistance.ConclusionsWe estimated a prevalence of clarithomycin-resistance of 31.8% in Santiago, Chile. Three of them harbor inactivating mutations in rdxA and 11 had missense mutations likely conferring metronidazole resistance. Our results require further confirmation. Nevertheless, they are significant as an initial approximation in re-evaluating the guidelines for H.pylori eradication currently used in Chile.

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Section: Resultsmentioning

confidence: 99%

Prevalence of clarithromycin resistance in Helicobacter pylori in Santiago, Chile, estimated by real-time PCR directly from gastric mucosa

et al. 2018

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“…Therefore, apart from antibiotic susceptibility, drug combinations are a matter for concern in H. pylori . On other hand, the possibility of a hetero-resistant status—i.e., the coexistence of susceptible and resistant H. pylori strains at different gastric sites in the same patient—may undermine the correct classification of antibiotic susceptibility in vitro [ 66 ]. The same result is expected when antibiotic susceptibility is genetically assessed using a culture-free, polymerase chain reaction-based tool, which overcomes the culture limitation of bacterial growth.…”

Section: Discussionmentioning

confidence: 99%

Culture-based antibiotic susceptibility testing for Helicobacter pylori infection: a systematic review

Francesco¹

2022

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Background Primary antibiotic resistance in Helicobacter pylori ( H. pylori ) strains is increasing worldwide, affecting therapy success. The use of therapies tailored on susceptibility pre-testing at culture has been proposed, but data are still conflicting. Method We performed a systematic review to evaluate the role of a culture-based therapeutic approach for H. pylori treatment, taking into account the sensitivity of culture and the success rates achieved with tailored therapies in different therapeutic steps. Results We analyzed data from 51 studies. Overall, H. pylori strains were isolated in 80.7% of 7889 patients, the success rates being 78.1%, 77.5%, 86.3% and 86.6%, before first-, second-, third-line or more therapies, respectively. In comparative studies, the infection was cured in 89.9% of 2052 patients treated with tailored therapies, and in 77.6% of 2516 patients receiving empiric therapy (P<0.001). However, in the subanalysis, the tailored approach achieved optimal eradication rates (>90%) only when it was applied before first- and second-line therapies, but not before third-line or more attempts (<80%). Moreover, no significant difference emerged between the 2 approaches when data from only the most recent (last 5 years) studies were considered, as well as in those performed in Western populations. Conclusions The attempt to achieve antibiotic susceptibility testing before treatment failed in 20% of infected patients managed in dedicated laboratories. Culture-tailored therapies administered after 2 or more therapies achieved suboptimal eradication rates. The role of bacterial culture in patients whose therapeutic management failed to eradicate H. pylori probably needs to be corroborated by further data.

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“…Therefore, a bacterial strain tested as susceptible in vitro could actually behave as resistant in vivo . Another factor that might affect the discrepancy between in vivo and in vitro results could be the presence of a heteroresistant status—namely, the coexistence of susceptible and resistant strains, either intra-niche (i.e., at the same gastric site) or inter-niche (antrum and gastric body)—that has been clearly demonstrated for H. pylori infection [ 31 , 32 ]. Generally, only 1-2 gastric biopsies are taken to perform culture in clinical practice.…”

Section: Introductionmentioning

confidence: 99%

Helicobacter pylori culture: from bench to bedside

Zullo¹

2022

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Helicobacter pylori ( H. pylori ) infection is a widespread infection that causes various gastroduodenal diseases and some extraintestinal disorders. Curing this infection remains challenging for clinicians, mainly because of bacterial resistance towards the few available antibiotics. Therefore, as for other infectious diseases, therapeutic approaches should be opportunely designed using the principles of antimicrobial stewardship. Theoretically, only susceptibility-based antimicrobial therapy should be considered as appropriate for treating this infection. Unfortunately, H. pylori owns some particular characteristics that make the infection slightly peculiar. More specifically, it is “fastidious” about growing in culture, and its isolation is not easily achieved, even in dedicated laboratories that, to make matters worse, are only scantily spread among countries. We examined the pros and cons of bacterial culture for antibiotic susceptibility testing before different therapy lines, and its applicability in the real clinical life.

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Helicobacter pylori clarithromycin resistance assessment: are gastric antral biopsies sufficient?

Cited by 5 publications

References 15 publications

Prevalence of clarithromycin resistance in Helicobacter pylori in Santiago, Chile, estimated by real-time PCR directly from gastric mucosa

Prevalence of clarithromycin resistance in Helicobacter pylori in Santiago, Chile, estimated by real-time PCR directly from gastric mucosa

Culture-based antibiotic susceptibility testing for Helicobacter pylori infection: a systematic review

Helicobacter pylori culture: from bench to bedside

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