摘要

欧洲养鱼场在环境和食物链中抗微生物药物扩散中的作用，以及它们被临床相关抗微生物细菌污染的可能来源鲜为人知。本研究旨在评估葡萄牙农村鳟鱼养殖场对环境和食物链中具有耐药性和假定毒力基因的肠球菌扩散的贡献，并确定养殖场污染源。我们还使用流行病学截止( ECOFFs )评估了低水平抗微生物药物肠球菌的存在。肠球菌属。( n = 391 )从上游、内部和下游鳟鱼水槽、饲料、鳟鱼( 2种水产养殖；未使用抗生素)和市售鳟鱼( 8家超市)对四环素、红霉素、环丙沙星、氯霉素、喹那普汀-达尔福什汀、呋喃妥因或氨基糖苷类药物表现出不同的耐药性。上游、内部和下游鳟鱼养殖池样品的耐药率相似( P > 0.05 )，说明供水养殖池是多药耐药( MDR )菌株的来源。然而，与上游样品相比，MDR屎肠球菌在饲料、鳟鱼养殖池和鳟鱼中的优势表明饲料是一种额外的水产养殖污染源。通过临床断点观察对氨苄青霉素和庆大霉素敏感但通过ECOFFs断点对这些抗菌剂具有低水平抗性屎肠球菌和粪肠球菌是令人关注的，因为它们可能在整个继发性遗传事件中进化到具有人类临床影响的抗性水平。观察到携带铜耐受性( tcrB / cueO )、假定毒力或通常与临床菌株相关的其它基因(例如，具有IS16 / ptsD / sgrA的屎钙)的多个MDR克隆，其中一些克隆在不同的样品中(例如，上游和鳟鱼池内)。它们包括主要的人和动物肠球菌谱系，提示人和非水生动物起源。结果突出表明，需要确定抗微生物基因/细菌的最大接受水平，以评估水质并监测饲料中的抗微生物菌株，这是维持可持续水产养殖生产的基本要求。

The role of European fish farms in the spread of antimicrobial-resistance in the environment and food chain, as well as possible sources of their contamination by clinically relevant antimicrobial-resistance bacteria is scarcely known. This study aimed to assess the contribution of Portuguese rural trout farms on dispersion of Enterococcus with antimicrobial-resistance and putative virulence genes in the environment and food chain, as well as to identify farms contamination sources. We also assessed the presence of Enterococcus with low-levels of antimicrobial-resistance using epidemiological cut-offs (ECOFFs).Enterococcus spp. (n = 391) from water/sediment recovered upstream, within and downstream trout tanks, feed, trout (2 aquacultures; no antibiotic use) and marketed trout (8 supermarkets) showed variable resistance to tetracycline, erythromycin, ciprofloxacin, chloramphenicol, quinupristin-dalfopristin, nitrofurantoin or aminoglycosides. Antimicrobial-resistance rates were similar among upstream, within and downstream trout tank samples (P > 0.05), positioning water-supplying aquacultures as a source of multidrug-resistant (MDR) strains. Nevertheless, predominance of MDR E. faecium in feed, trout tanks and trout comparing to upstream samples, suggests feed as an additional aquaculture contamination source. The observation of E. faecium and E. faecalis susceptible to ampicillin and gentamicin by clinical breakpoints but with low-levels of resistance to those antimicrobials by ECOFFs breakpoints is of concern, as they might evolve throughout secondary genetic events to resistance levels with human clinical impact. Multiple MDR clones carrying copper tolerance (tcrB/cueO), putative virulence or other genes often associated with clinical strains (e.g. E. faecium with IS16/ptsD/sgrA) were observed, some in distinct samples (e.g. upstream and within trout tanks). They included major human and animal Enterococcuslineages, suggesting human and non-aquatic animal origins. The results highlight the need to define the maximum acceptance level of antimicrobial-resistance genes/bacteria to assess water quality and to monitor antimicrobial-resistance strains on feed, essential requirements to maintain a sustainable aquaculture production.

https://www.sciencedirect.com/science/article/pii/S0048969717336987