biostudies-literatureZaragoza GInstituto de Salud Carlos III, Ministerio de Ciencia e Innovación and Unión Europea–NextGenerationEUInstituto de Salud Carlos IIICIBER—Consorcio Centro de Investigación Biomédica en RedCIBER -Consorcio Centro de Investigación Biomédica en Red (CB21/13/00095; CIBERINFEC), Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación and Unión Europea - NextGenerationEU. Instituto de Salud Carlos III (MePRAM Project, PMP22/00092), Ins218https://www.ebi.ac.uk/biostudies/studies/S-EPMC10967553biostudies-literatureUnknown13(3)<i>Escherichia coli</i> isolates that are resistant to cefixime and amoxicillin/clavulanic acid, but apparently susceptible to cefuroxime, with no ESBL identified, were initially detected in Madrid from urine samples in 2019. Throughout 2020 and 2021, all cases of community UTI by <i>E. coli</i> from six health areas in Madrid were studied. A representative sample of 23 cases was selected for further studies. The broth microdilution method and the agar diffusion method were performed to determine the antibiotic susceptibility. WGS was carried out for phylogeny, resistome and virulome analysis. Community consumption of third-generation oral cephalosporins in Madrid (2017-2021) was analyzed. A total of 582 (1.3%) <i>E. coli</i> isolates had the mentioned resistance profile. The mutation at pAntibiotics (Basel, Switzerland)Community Emergence of Cefixime-Resistant <i>Escherichia coli</i> Belonging to ST12 with Chromosomal AmpC Hyperproduction.PMC10967553CB21/13/00095CIBERINFECCIBER -Consorcio Centro de Investigación Biomédica en Red (CB21/13/00095; CIBERINFEC), Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación and Unión Europea - NextGenerationEU. Instituto de Salud Carlos III (MePRAM Project, PMP22/00092), InsPMP22/00092Alos JIZaragoza GGonzalez-Prieto AOteo-Iglesias JPerez-Vazquez MVillar-Gomara LfalseCommunity Emergence of Cefixime-Resistant <i>Escherichia coli</i> Belonging to ST12 with Chromosomal AmpC Hyperproduction.<i>Escherichia coli</i> isolates that are resistant to cefixime and amoxicillin/clavulanic acid, but apparently susceptible to cefuroxime, with no ESBL identified, were initially detected in Madrid from urine samples in 2019. Throughout 2020 and 2021, all cases of community UTI by <i>E. coli</i> from six health areas in Madrid were studied. A representative sample of 23 cases was selected for further studies. The broth microdilution method and the agar diffusion method were performed to determine the antibiotic susceptibility. WGS was carried out for phylogeny, resistome and virulome analysis. Community consumption of third-generation oral cephalosporins in Madrid (2017-2021) was analyzed. A total of 582 (1.3%) <i>E. coli</i> isolates had the mentioned resistance profile. The mutation at p2024-01-01T00:00:00Z2024 Feb2025-04-21T21:30:15.742Z2025-04-05T18:25:47.937ZS-EPMC109675533853465310.3390/antibiotics13030218