Viet Nam is the world’s fifth largest producer of pork meat. Salmonella is frequently found at farm level; however, risk factors for Salmonella infection in pigs have not been thoroughly investigated in the production system. In the current study, 123 commercial feed samples were obtained from 103 small, medium and large-scale pig farms in Viet Nam and investigated for the presence of Salmonella in 25 g of feed using the ISO 6579:2002/Cor 1:2004 method. Salmonella was detected in five samples (4.1%; 95% CI 1.75–9.16%). All five samples were found to contain S. Weltevreden as the only serovar. The isolates were subjected to phenotypic and whole genome sequencing analysis for further characterization. They all belonged to ST365 and were sensitive to the 14 antimicrobials tested. Four strains were found to belong to the continental lineage of S. Weltevreden, while one isolate was of the island type. This isolate, contrary to the remaining four isolates contained a prophage homolog to the Vibrio prophage X-29. The findings of only S. Weltevreden, which is often isolated from fish and aquatic samples, suggests that fishmeal used in the feed preparation was a likely source of contamination.

越南是世界第五大猪肉生产国。沙门氏菌经常在农场一级发现。但是，尚未在生产系统中对猪中沙门氏菌感染的危险因素进行彻底调查。在当前的研究中，从越南的103个小型，中型和大型养猪场获得了123种商业饲料样品，并使用ISO 6579：2002 / Cor 1：2004方法对25 g饲料中沙门氏菌的存在进行了调查。在五个样本中检出沙门氏菌（4.1％； 95％CI 1.75–9.16％）。发现所有五个样本都包含S。Weltevreden是唯一的血清型。对分离物进行表型和全基因组测序分析以进一步表征。它们都属于ST365，并且对所测试的14种抗菌药物敏感。发现四株属于S. Weltevreden的大陆谱系，而其中一株为岛型。与其余四个分离株相反，该分离株包含与弧菌噬菌体X-29的噬菌体同源物。仅S的发现。Weltevreden通常从鱼类和水生样品中分离出来，这表明饲料制备中使用的鱼粉可能是污染源。