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Background: Helicobacter pylori (H. pylori) infection is the leading cause of both peptic ulcers and gastric tumors, including low-grade MALT-lymphoma and adenocarcinoma. Although it is decreasing in developed countries, H. pylori prevalence remains high in developing areas, mainly due to low socio-economic levels, and the potential consumption of contaminated water. Moreover, a dierent pattern of primary antibiotic resistance is expected in their H. pylori isolates, potentially aecting the ecacy of standard eradication therapies. Indeed, a previous study showed the eradication rate following triple therapy was distinctly lower in dyspeptic H. pylori infected immigrants living in Italy as compared to Italian patients. Aims: to evaluate the resistance pattern in H. pylori isolates from immigrant patients in Italy, and the success rate of first-line therapy in these patients. Materials and Methods: This retrospective study evaluated data of consecutive immigrant patients, diagnosed with H. pylori infection in a single center (Bologna, Italy) between January 2009 and January 2019. Patients underwent first-line therapy with either sequential or Pylera® (Allergan USA, Inc. Madison, NJ, USA) therapy. Results: A total of 609 immigrants were diagnosed with H. pylori infection during the study period, but 264 previously received an eradication therapy. Therefore, the study was focused on 294 out of 345 naïve patients with a successful bacterial culture with antibiogram. Latin America immigrants had the highest overall resistance rate. Levofloxacin resistance rate was significantly higher in Latin Americans and Asians as compared with Europeans. Based on resistance patterns, sequential therapy showed a clear decreasing trend in eradication rates. Conclusions: while antibiotic resistance rates are generally increasing worldwide, Pylera® seems to achieve a good performance as first-line treatment in all naïve foreigner patients, except for Africans.

Background and aims Helicobacter pylori prevalence remains high worldwide, especially in developing areas where infection acquisition occurs in early childhood. H. pylori eradication fails in a definite number of patients, despite one or more therapeutic attempts. Curing these patients is progressively more difficult, due to development of antibiotic resistance. While the cure rate of first-line therapies in foreigners was found to be different from that of Italians, no data are available on rescue therapies. Materials and methods Consecutive foreigner patients with H. pylori infection following at least one therapy failure were enrolled. All patients underwent upper endoscopy with gastric biopsies used for both histologic examination and culture/susceptibility test. Rescue therapies administered accordingly to susceptibility testing were rifabutin-based therapy, levofloxacin-based therapy, sequential. Pylera was prescribed regardless the resistance pattern. Results A total of 103 (M/F: 27/76, mean age: 41.9 y, range: 18 to 85) were enrolled. The overall resistance rates toward clarithromycin, metronidazole, and levofloxacin were 76.7%, 66%, and 42.7%, respectively, with triple resistance present in 33.9% of bacterial isolates. Eradication rates were 71.4% on 40 patients for rifabutin-based therapy, 82.8% on 42 cases for levofloxacin-based therapy, 75% on 11 patients treated with sequential therapy, and 100% on 10 cases who received Pylera regimen. Conclusions To our knowledge, this is the first study assessing H. pylori eradication rates in foreigner patients, who failed at least one therapeutic attempt, managed in Italy. Even by using a culture-based approach, the infection was not cured in a definite number of patients.

Helicobacter pylori (H. pylori) eradication fails in a definite amount of patients despite one or more therapeutic attempts. Curing these patients is progressively more difficult, due to development of antibiotic resistance. Current guidelines suggest testing antibiotic susceptibility in H. pylori isolates following two therapeutic attempts. Aim: to evaluate the development of antibiotic resistance, MIC values trends and therapeutic outcomes in patients who failed at least one H. pylori eradication therapy. Methods: consecutive patients, referred to perform upper gastrointestinal endoscopy (UGIE) to our Unit from January 2009 to January 2019 following at least one therapeutic attempt were considered. Bacterial resistance towards clarithromycin, metronidazole and levofloxacin was tested. Patients received either a susceptibility-guided therapy or Pylera&reg, Results: a total of 1223 patients were H. pylori positive, and antibiotic susceptibility was available for 1037. The rate of antibiotic resistance and MIC values significantly increased paralleling the number of previous therapeutic attempts. Eradication rates of antibiogram-tailored therapies remained stable, except for the sequential therapy if used as a third line. As a rescue treatment, the Pylera&reg, therapy achieved cure rates comparable to those of the other culture-guided therapies. Conclusions: A significant increase in the secondary resistance towards the three tested antibiotics was observed, both as rate and MIC values, in correlation with the number of therapy failures. These findings should be considered when administering an empirical second-line therapy. Pylera&reg, therapy eradication rates are comparable to culture-tailored therapies.

Background and aims: Only a few antimicrobials are effective against H. pylori, and antibiotic resistance is an increasing problem for eradication therapies. In 2017, the World Health Organization categorized clarithromycin resistant H. pylori as a “high-priority” bacterium. Standard antimicrobial susceptibility testing can be used to prescribe appropriate therapies but is currently recommended only after the second therapeutic failure. H. pylori is, in fact, a “fastidious” microorganism; culture methods are time-consuming and technically challenging. The advent of molecular biology techniques has enabled the identification of molecular mechanisms underlying the observed phenotypic resistance to antibiotics in H. pylori. The aim of this literature review is to summarize the results of original articles published in the last ten years, regarding the use of Next Generation Sequencing, in particular of the whole genome, to predict the antibiotic resistance in H. pylori.Methods: a literature research was made on PubMed. The research was focused on II and III generation sequencing of the whole H. pylori genome. Results: Next Generation Sequencing enabled the detection of novel, rare and complex resistance mechanisms. The prediction of resistance to clarithromycin, levofloxacin and amoxicillin is accurate; for other antimicrobials, such as metronidazole, rifabutin and tetracycline, potential genetic determinants of the resistant status need further investigation.