CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, 1300-477, Lisbon, Portugal.
Technology, Quality and Food Safety Lab, CECAV, Depart. Veterinary Science, UTAD, 5000-801, Vila Real, Portugal.
Vet Microbiol. 2019 Dec;239:108457. doi: 10.1016/j.vetmic.2019.108457. Epub 2019 Oct 15.
Pork is one of the most common vehicles of non-typhoid foodborne Salmonella, with the slaughterhouse representing a key point for the infection of pigs and carcass contamination. By comparing matching samples taken from animals at the dirty (skin) and clean (inner and outer carcass surface) areas of the slaughterline, this study aimed to assess potential Salmonella contamination routes of pig carcasses within a Portuguese abattoir. Forty-four Salmonella isolates were retrieved from 120 pigs, and further characterized through pheno and genotypical methods. Most frequent serotypes found were Salmonella 4, [5],12:i:- (47.7%), Salmonella Rissen (40.9%) and Salmonella Derby (11.4%). Isolates were most commonly collected from the skin of pigs sampled at the dirty area (59.1%), followed by the inner (38.1%) and outer (9.1%) carcass surface sampled at the clean area. Most isolates (79.5%) were considered to be multidrug resistant and all harbored the virulence associated genes invA, invH, sopB, stn, slyA, phoP, phoQ and agfA. PFGE analysis revealed that most bacterial isolates belonging to the same serotype, recovered from animals from different farms, and slaughtered at separate days were genetically undistinguishable. Furthermore, our findings suggest that Salmonella Rissen might have an increased ability to endure on the slaughterhouse environment when compared with the other serotypes. Concluding, this study shows that the slaughterhouse may be a key point for the dissemination of resistant and virulent Salmonella strains, which stresses the importance of the implementation of good hygiene practices at the slaughterhouse and of the application of corrective measures to avoid cross-contamination.
猪肉是食源性非伤寒沙门氏菌的常见宿主之一，屠宰场是猪感染和胴体污染的关键点。本研究通过比较屠宰线上脏（皮肤）和净（内外胴体表面）区域动物的匹配样本，旨在评估葡萄牙屠宰场猪胴体中沙门氏菌的潜在污染途径。从 120 头猪中分离出 44 株沙门氏菌，并通过表型和基因型方法进一步进行特征分析。发现最常见的血清型为沙门氏菌 4,[5],12:i:-（47.7%）、沙门氏菌 Rissen（40.9%）和沙门氏菌 Derby（11.4%）。从脏区采样的猪皮肤中分离到的分离株最为常见（59.1%），其次是净区采样的内（38.1%）和外（9.1%）胴体表面。大多数分离株（79.5%）被认为是多药耐药的，所有分离株都携带与毒力相关的基因 invA、invH、sopB、stn、slyA、phoP、phoQ 和 agfA。PFGE 分析表明，属于同一血清型的大多数细菌分离株，从来自不同农场的动物中分离出来，并在不同的日子屠宰，在遗传上是无法区分的。此外，我们的研究结果表明，与其他血清型相比，沙门氏菌 Rissen 可能具有在屠宰场环境中存活的能力。总之，本研究表明，屠宰场可能是耐药和毒力沙门氏菌传播的关键环节，这强调了在屠宰场实施良好卫生实践和应用纠正措施以避免交叉污染的重要性。
