DTU Food, Technical University of Denmark, Building 301, 2800, Lyngby, Denmark.
Mol Genet Genomics. 2010 May;283(5):469-84. doi: 10.1007/s00438-010-0532-9. Epub 2010 Mar 31.
Escherichia coli is a highly versatile species encompassing a diverse spectrum of strains, i.e. from highly virulent isolates causing serious infectious diseases to commensals and probiotic strains. Although much is known about bacterial pathogenicity in E. coli, the understanding of which genetic determinants differentiates a virulent from an avirulent strain still remains limited. In this study we designed a new comparative genomic hybridization microarray based on 31 sequenced E. coli strains and used it to compare two E. coli strains used as prophylactic agents (i.e. Nissle 1917 and 83972) with the highly virulent uropathogen CFT073. Only relatively minor genetic variations were found between the isolates, suggesting that the three strains may have originated from the same virulent ancestral parent. Interestingly, Nissle 1917 (a gut commensal strain) was more similar to CFT073 with respect to genotype and phenotype than 83972 (an asymptomatic bacteriuria strain). The study indicates that genetic variations (e.g. mutations) and expression differences, rather than genomic content per se, contribute to the divergence in disease-causing ability between these strains. This has implications for the use of virulence factors in epidemiological research, and emphasizes the need for more comparative genomic studies of closely related strains to compare their virulence potential.
大肠杆菌是一种高度多样的物种，包含了广泛的菌株，即从引起严重传染病的高毒力分离株到共生菌和益生菌株。尽管人们对大肠杆菌的细菌致病性有了很多了解，但对于区分毒力菌株和非毒力菌株的遗传决定因素的理解仍然有限。在这项研究中，我们设计了一种基于 31 株已测序大肠杆菌菌株的新型比较基因组杂交微阵列，并将其用于比较两种用作预防剂的大肠杆菌菌株（即尼尔斯 1917 株和 83972 株）与高度毒力的尿路病原体 CFT073。在分离株之间仅发现相对较小的遗传变异，这表明这三个菌株可能起源于相同的毒力祖先。有趣的是，就基因型和表型而言，尼尔斯 1917 株（肠道共生菌）比 83972 株（无症状菌尿株）与 CFT073 更相似。该研究表明，遗传变异（例如突变）和表达差异而不是基因组内容本身导致了这些菌株致病能力的差异。这对在流行病学研究中使用毒力因子有影响，并强调需要对密切相关的菌株进行更多的比较基因组研究，以比较它们的毒力潜力。
