Campos, Maria Jorge GeraldesBaptista, Teresa Maria CoelhoValdez Álvarez, Christian Andrés2020-08-042020-08-042020-07-27http://hdl.handle.net/10400.8/5042Currently, antibiotic resistance is presented globally as a serious problem that worsens daily, and since more resistant bacteria, with the capacity to transfer genes keep emerging, it becomes a topic of uttermost importance. Mollusks are a highly appreciated food, however, these organisms feed through filtering, which leads to the accumulation of a varied community of microorganisms in its tissues, and when consumed raw or unproperly cooked, the transference of genes, from its microorganisms to the human gastrointestinal flora may occur. The interaction between these two groups of microorganisms can generate the transference of resistance genes. The main objective of this study consists in the screening of genetic determinants of resistance to antimicrobial compounds present in enterobacteria and Vibrio isolated from mollusks collected from two geographical zones in Portugal. Both group of microorganisms were isolated in selective media TCBS and Chromocult from Ruditapes decussatus and Ruditapes philippinarum samples from Óbidos lagoon, and Ruditapes decussatus samples from Ria Formosa in Algarve. 43 microorganisms belonging to Vibrio genus and 18 enterobacteria were isolated. Optimal growth conditions for Vibrio were stablished, with best results determined as 28°C in both selective (TCBS) and non-selective media (Muller-Hinton) supplemented with NaCl (1,5%). Phenotypic resistance tests to five antimicrobials, namely cefotaxime, imipenem, ciprofloxacin, meropenem and colistin, were carried out. The screening of 23 resistance genes was done through PCR (qnrS, qnrA, qnrB, qnrC, qnrD, qepA, blaIMP, blaVIM, blaKPC, blaNDM, blaOXA, blaCTX-M, blaSHV , blaTEM, mcr-1, mcr-2, mcr-3, mcr-4, mcr-5, mcr-6, mcr-7, mcr-8, mcr-9). Phenotypic resistance to colistin and its respective genetic marker mcr-1, were found in three Vibrio spp. Isolates, EV07V isolated from Ruditapes decussatus from Algarve and NJ21V and NJ22V isolated from Ruditapes philippinarum from Óbidos.porAntimicrobial resistanceclamscolistinenterobacteriamcr-1Vibriomaster thesis202506398