Kang Min-Su, Besser Thomas E, Hancock Dale D, Porwollik Steffen, McClelland Michael, Call Douglas R
Department of Veterinary Microbiology and Pathology, Washington State University, 402 Bustad Hall, Pullman, WA 99164-7040, USA.
Appl Environ Microbiol. 2006 Nov;72(11):6938-47. doi: 10.1128/AEM.01368-06. Epub 2006 Sep 8.
Genetic elements specific to recent and contemporary epidemic strains of Salmonella enterica were identified using comparative genomic analysis. Two epidemic multidrug-resistant (MDR) strains, MDR Salmonella enterica serovar Typhimurium definitive phage type 104 (DT104) and cephalosporin-resistant MDR Salmonella enterica serovar Newport, and an epidemic pansusceptible strain, Salmonella serovar Typhimurium DT160, were subjected to Salmonella gene microarray and suppression subtractive hybridization analyses. Their genome contents were compared with those of coexisting sporadic strains matched by serotype, geographic and temporal distribution, and host species origin. These paired comparisons revealed that epidemic strains of S. enterica had specific genes and gene regions that were shared by isolates of the same subtype. Most of these gene sequences are related to mobile genetic elements, including phages, plasmids, and plasmid-like and transposable elements, and some genes may encode proteins conferring growth or survival advantages. The emergence of epidemic MDR strains may therefore be associated with the presence of fitness-associated genetic factors in addition to their antimicrobial resistance genes.
通过比较基因组分析确定了肠炎沙门氏菌近期和当代流行菌株特有的遗传元件。对两株流行的多重耐药（MDR）菌株，即多重耐药的肠炎沙门氏菌鼠伤寒血清型104型（DT104）和耐头孢菌素的多重耐药肠炎沙门氏菌新港血清型，以及一株流行的全敏感菌株，即鼠伤寒沙门氏菌DT160，进行了沙门氏菌基因微阵列和抑制性消减杂交分析。将它们的基因组内容与通过血清型、地理和时间分布以及宿主物种来源匹配的共存散发病原菌株的基因组内容进行比较。这些配对比较表明，肠炎沙门氏菌的流行菌株具有特定的基因和基因区域，这些基因和基因区域为同一亚型的分离株所共有。这些基因序列大多与可移动遗传元件有关，包括噬菌体、质粒、类质粒和转座元件，一些基因可能编码赋予生长或生存优势的蛋白质。因此，流行的多重耐药菌株的出现可能除了与其抗微生物耐药基因有关外，还与适应性相关遗传因素的存在有关。
