Statens Serum Institut, Bacterial Typing, Copenhagen S, Denmark.
BMC Microbiol. 2010 Mar 31;10:96. doi: 10.1186/1471-2180-10-96.
Salmonella enterica subsp. enterica is one of the leading food-borne pathogens in the USA and European countries. Outcome of human Salmonella serotype Typhimurium infections ranges from mild self-limiting diarrhoea to severe diarrhoea that requires hospitalization. Increased knowledge of the mechanisms that are responsible for causing infection and especially the severity of infection is of high interest.
Strains were selected from patients with mild infections (n = 9) and patients with severe infections (n = 9) and clinical data allowed us to correct for known underlying diseases. Additionally, outbreak isolates (n = 3) were selected. Strains were analyzed on a DNA-DNA microarray for presence or absence of 281 genes covering marker groups of genes related to pathogenicity, phages, antimicrobial resistance, fimbriae, mobility, serotype and metabolism. Strains showed highly similar profiles when comparing virulence associated genes, but differences between strains were detected in the prophage marker group. The Salmonella virulence plasmid was present in 72% of the strains, but presence or absence of the virulence plasmid did not correspond to disease symptoms. A dendrogram clustered strains into four groups. Clustering confirmed DT104 as being a clonal phagetype. Clustering of the remaining strains was mainly correlated to presence or absence of the virulence plasmid and mobile elements such as transposons. Each of the four clusters in the tree represented an almost equal amount of strains causing severe or mild symptoms of infection.
We investigated clinical significance of known virulence factors of Salmonella serotype Typhimurium strains causing different disease symptoms, and conclude that the few detected differences in Salmonella serotype Typhimurium do not affect outcome of human disease.
沙门氏菌肠亚种是美国和欧洲国家主要的食源性病原体之一。人类感染沙门氏菌血清型肠炎的结果从轻度自限性腹泻到需要住院治疗的严重腹泻不等。增加对导致感染的机制，尤其是感染严重程度的了解是非常重要的。
从轻度感染患者（n=9）和严重感染患者（n=9）中选择菌株，临床数据允许我们纠正已知的潜在疾病。此外，还选择了爆发分离株（n=3）。使用 DNA-DNA 微阵列分析菌株，以确定与致病性、噬菌体、抗生素耐药性、菌毛、可移动性、血清型和代谢相关的基因标记组中 281 个基因的存在或缺失。在比较与毒力相关的基因时，菌株显示出高度相似的图谱，但在噬菌体标记组中检测到菌株之间的差异。沙门氏菌毒力质粒存在于 72%的菌株中，但毒力质粒的存在与否与疾病症状不对应。系统发育树将菌株聚类为四个组。聚类证实 DT104 是一种克隆噬菌体型。其余菌株的聚类主要与毒力质粒和可移动元件（如转座子）的存在或缺失相关。树中的四个簇中的每一个都代表了引起严重或轻度感染症状的菌株数量几乎相等。
我们研究了导致不同疾病症状的肠炎沙门氏菌血清型菌株的已知毒力因子的临床意义，并得出结论，沙门氏菌血清型肠炎中检测到的差异很少影响人类疾病的结果。
