{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:35:03Z","timestamp":1760060103986,"version":"build-2065373602"},"reference-count":45,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2025,8,1]],"date-time":"2025-08-01T00:00:00Z","timestamp":1754006400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"FCT\u2014Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia, I.P.","doi-asserted-by":"publisher","award":["UIDB\/05937\/2020"],"award-info":[{"award-number":["UIDB\/05937\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>Background\/Objectives: Helicobacter pylori (H. pylori) is a common gastric pathogen linked to gastritis, gastroduodenal ulcers, and gastric cancer. Rising antimicrobial resistance (AMR) poses challenges for effective treatment and has prompted the WHO to classify H. pylori as a high-priority pathogen. This study aimed to detect the prevalence of AMR genes in H. pylori-positive gastric samples from patients in Algarve, Portugal, where regional data is scarce. Methods: Eighteen H. pylori-positive gastric biopsy samples from patients undergoing upper gastrointestinal endoscopy were analyzed. PCR and sequencing were used to identify genes associated with resistance to amoxicillin (Pbp1A), metronidazole (rdxA, frxA), tetracycline (16S rRNA mutation) and clarithromycin (23S rRNA). Sequence identity and homologies were verified using tBLASTx and the Comprehensive Antibiotic Resistance Database (CARD). Results: Out of the 18 H. pylori-positive samples, 16 (88.9%) contained at least one AMR gene. The most frequent genes were rdxA (83.3%) and frxA (66.7%) for metronidazole resistance, and the 16S rRNA mutation (66.7%) for tetracycline. Resistance to amoxicillin and clarithromycin was detected in 27.8% and 16.7% of cases, respectively. Most samples (72.2%) had multiple resistance genes. A significantly strong association was found between female sex and the presence of the rdxA gene (p = 0.043). Conclusions: The study reveals a high prevalence of H. pylori resistance genes in Algarve, particularly against metronidazole and tetracycline. These findings highlight the need for local surveillance and tailored treatment strategies. Further research with larger populations is warranted to assess regional resistance patterns and improve eradication efforts.<\/jats:p>","DOI":"10.3390\/antibiotics14080780","type":"journal-article","created":{"date-parts":[[2025,8,6]],"date-time":"2025-08-06T10:13:51Z","timestamp":1754475231000},"page":"780","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Molecular Detection of Multiple Antimicrobial Resistance Genes in Helicobacter pylori-Positive Gastric Samples from Patients Undergoing Upper Gastrointestinal Endoscopy with Gastric Biopsy in Algarve, Portugal"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6638-9782","authenticated-orcid":false,"given":"Francisco","family":"Cortez Nunes","sequence":"first","affiliation":[{"name":"Faculty of Medicine and Biomedical Sciences, University of Algarve, 8005-139 Faro, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-6028-9985","authenticated-orcid":false,"given":"Catarina","family":"Aguieiras","sequence":"additional","affiliation":[{"name":"Servi\u00e7o de Gastroenterologia, Unidade Local de Sa\u00fade do Algarve\u2013Hospital de Faro, 8005-139 Faro, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mauro","family":"Calhindro","sequence":"additional","affiliation":[{"name":"Servi\u00e7o de Medicina Interna, Unidade Local de Sa\u00fade do Algarve\u2013Hospital de Portim\u00e3o, 8500-338 Portim\u00e3o, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ricardo","family":"Louro","sequence":"additional","affiliation":[{"name":"Hospital Particular do Algarve\u2013Unidade de Alvor, 8000-386 Faro, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bruno","family":"Peixe","sequence":"additional","affiliation":[{"name":"Servi\u00e7o de Gastroenterologia, Unidade Local de Sa\u00fade do Algarve\u2013Hospital de Faro, 8005-139 Faro, Portugal"},{"name":"Servi\u00e7o de Medicina Interna, Unidade Local de Sa\u00fade do Algarve\u2013Hospital de Portim\u00e3o, 8500-338 Portim\u00e3o, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Patr\u00edcia","family":"Queir\u00f3s","sequence":"additional","affiliation":[{"name":"Faculty of Medicine and Biomedical Sciences, University of Algarve, 8005-139 Faro, Portugal"},{"name":"Servi\u00e7o de Medicina Interna, Unidade Local de Sa\u00fade do Algarve\u2013Hospital de Portim\u00e3o, 8500-338 Portim\u00e3o, Portugal"},{"name":"Servi\u00e7o de Gastroenterologia, Unidade Local de Sa\u00fade do Algarve\u2013Hospital de Portim\u00e3o, 8500-338 Portim\u00e3o, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3453-3978","authenticated-orcid":false,"given":"Pedro","family":"Castelo-Branco","sequence":"additional","affiliation":[{"name":"Faculty of Medicine and Biomedical Sciences, University of Algarve, 8005-139 Faro, Portugal"},{"name":"Algarve Biomedical Center Research Institute (ABC Ri), University of Algarve, 8005-139 Faro, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1236-3012","authenticated-orcid":false,"given":"Teresa Letra","family":"Mateus","sequence":"additional","affiliation":[{"name":"CISAS\u2014Center for Research and Development in Agrifood Systems and Sustainability, Escola Superior Agr\u00e1ria, Instituto Polit\u00e9cnico de Viana do Castelo, 4900-437 Viana do Castelo, Portugal"},{"name":"EpiUnit ITR, Instituto de Sa\u00fade P\u00fablica, Universidade do Porto, 4050-091 Porto, Portugal"},{"name":"Veterinary and Animal Research Centre (CECAV), Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Universidade de Tr\u00e1s-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Sun, Q., Yuan, C., Zhou, S., Lu, J., Zeng, M., Cai, X., and Song, H. 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