Aquaculture is a growing sector, providing several products for human consumption, and it is therefore important to guarantee its quality and safety. This study aimed to contribute to the knowledge of bacterial composition of Crassostrea gigas, Mytilus spp. and Ruditapes decussatus, and the antibiotic resistances/resistance genes present in aquaculture environments. Two hundred and twenty-two bacterial strains were recovered from all bivalve mollusks samples belonging to the Aeromonadaceae, Bacillaceae, Comamonadaceae, Enterobacteriaceae, Enterococcaceae, Micrococcaceae, Moraxellaceae, Morganellaceae, Pseudomonadaceae, Shewanellaceae, Staphylococcaceae, Streptococcaceae, Vibrionaceae, and Yersiniaceae families. Decreased susceptibility to oxytetracycline prevails in all bivalve species, aquaculture farms and seasons. Decreased susceptibilities to amoxicillin, amoxicillin/clavulanic acid, cefotaxime, cefoxitin, ceftazidime, chloramphenicol, florfenicol, colistin, ciprofloxacin, flumequine, nalidixic acid and trimethoprim/sulfamethoxazole were also found. This study detected six qnrA genes among Shewanella algae, ten qnrB genes among Citrobacter spp. and Escherichia coli, three oqxAB genes from Raoultella ornithinolytica and bla_TEM-1 in eight E. coli strains harboring a qnrB19 gene. Our results suggest that the bacteria and antibiotic resistances/resistance genes present in bivalve mollusks depend on several factors, such as host species and respective life stage, bacterial family, farm’s location and season, and that is important to study each aquaculture farm individually to implement the most suitable measures to prevent outbreaks.

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评估水产养殖场采集的双壳类软体动物的细菌群落组成和各自对抗生素的敏感性

水产养殖是一个不断发展的部门，提供多种供人类消费的产品，因此保证其质量和安全非常重要。本研究旨在有助于细菌组成的知识牡蛎，贻贝属。和Ruditapes decussatus，以及水产养殖环境中存在的抗生素抗性/抗性基因。第二百22株细菌由属于所有双壳类软体动物样品中回收Aeromonadaceae，芽孢杆菌，Comamonadaceae，肠杆菌，Enterococcaceae，微球菌，Moraxellaceae、摩根氏菌科、假单胞菌科、希瓦氏菌科、葡萄球菌科、链球菌科、弧菌科和耶尔森氏菌科。所有双壳贝类、水产养殖场和季节普遍对土霉素的敏感性降低。还发现对阿莫西林、阿莫西林/克拉维酸、头孢噻肟、头孢西丁、头孢他啶、氯霉素、氟苯尼考、粘菌素、环丙沙星、氟甲喹、萘啶酸和甲氧苄啶/磺胺甲恶唑的敏感性降低。这项研究发现6个qnrA中基因海藻希瓦氏菌，十qnrB中基因枸橼酸杆菌属 和大肠杆菌，来自Raoultella ornithinolytica 的三个oqxAB基因和bla _TEM-1在八个带有qnrB19基因的大肠杆菌菌株中。我们的研究结果表明，双壳类软体动物中存在的细菌和抗生素抗性/抗性基因取决于多种因素，例如宿主物种和各自的生命阶段、细菌家族、养殖场的位置和季节，这对于单独研究每个水产养殖场以实施预防爆发的最合适的措施。