1 Department of Veterinary Biosciences, Faculty of Animal Science and Veterinary Medicine, Nông Lâm University, Ho Chi Minh City, Vietnam.
2 Department of Pathology and Microbiology, University of Montreal, St-Hyacinthe, Quebec, Canada J2S 2M2.
J Food Prot. 2018 Sep;81(9):1459-1466. doi: 10.4315/0362-028X.JFP-17-408.
This study was carried out to evaluate the prevalence of Salmonella serogroups and serotypes and their virulence gene carriage in pig fecal samples from farms and slaughterhouses in some southern provinces of Vietnam. The presence of Salmonella was assessed based on culture enrichment of the collected samples and biochemical and serological analyses; 27.7% (51) of 184 samples were posititve for Salmonella. Based on the availability of antisera, serogroups were determined for 61% (31) of 51 isolates. Twenty isolates belonging to Salmonella serotypes Typhimurium (10 isolates), Anatum (8 isolates), Senftenberg (7 isolates), Paratyphi B (3 isolates), Paratyphi A (1 isolate), Montevideo (1 isolate), and Saintpaul (1 isolate) were further characterized by a multiplex PCR protocol targeting Salmonella invasion A and virulence plasmid C genes ( invA and spvC, respectively). Individual PCR assays were developed to detect genes for Salmonella enterotoxin ( stn) , Salmonella outer protein B ( sopB), and Salmonella fimbriae ( pef). Various carriage patterns were identified among tested isolates. The invA and sopB genes were found in all isolates, and the stn gene was found in 95% of the isolates. The spvC gene was found in only 5% of the Salmonella Typhimurium isolates. None of the isolates were positive for the pef gene. Among all isolates, the predominant genotypic virulence profile (virulotype) was characterized by the concomitant presence of invA, sopB, and stn in carrier strains. In contrast, two virulotypes comprising either invA, sopB, spvC, and stn or invA and sopB were identified for the Salmonella Typhimurium isolates. Virulotypes made up of multiple virulence genes were predominant in most Salmonella strains tested in this study, indicating that pigs might act as a reservoir for these virulent strains.
本研究旨在评估越南南部一些省份农场和屠宰场猪粪便样本中沙门氏菌血清群和血清型的流行情况及其携带的毒力基因。通过对采集样本进行培养富集和生化及血清学分析来评估沙门氏菌的存在；在 184 个样本中，有 27.7%（51 个）呈沙门氏菌阳性。根据抗血清的可用性，确定了 51 个分离株中的 61%（31 个）属于沙门氏菌血清群。20 个分离株属于沙门氏菌血清型鼠伤寒沙门氏菌（10 个分离株）、鸭沙门氏菌（8 个分离株）、森藤伯格沙门氏菌（7 个分离株）、乙型副伤寒沙门氏菌（3 个分离株）、甲型副伤寒沙门氏菌（1 个分离株）、蒙得维的亚沙门氏菌（1 个分离株）和圣保尔沙门氏菌（1 个分离株），进一步通过针对沙门氏菌侵袭 A 和毒力质粒 C 基因（分别为 invA 和 spvC）的多重 PCR 方案进行了特征描述。开发了个体 PCR 检测沙门氏菌肠毒素（stn）、沙门氏菌外膜蛋白 B（sopB）和沙门氏菌菌毛（pef）的基因。在测试的分离株中鉴定出了各种携带模式。所有分离株均检出 invA 和 sopB 基因，95%的分离株检出 stn 基因。仅 5%的鼠伤寒沙门氏菌分离株检出 spvC 基因。没有分离株检测出 pef 基因。在所有分离株中，主要的基因型毒力谱（毒力型）特征是携带菌株中同时存在 invA、sopB 和 stn。相反，在鼠伤寒沙门氏菌分离株中确定了两种毒力型，包括 invA、sopB、spvC 和 stn 或 invA 和 sopB。本研究中测试的大多数沙门氏菌菌株携带多种毒力基因的毒力型占优势，表明猪可能是这些毒力菌株的储存库。
