Kawahara K, Haraguchi Y, Tsuchimoto M, Terakado N, Danbara H
Department of Bacteriology, Kitasato Institute, Japan.
Microb Pathog. 1988 Feb;4(2):155-63. doi: 10.1016/0882-4010(88)90057-5.
A plasmid of 50 kilobases (kb) was found in all six strains of Salmonella choleraesuis studied, originally isolated from septicemic swine or man. A derivative cured of the 50 kb plasmid was isolated after treatment with novobiocin, and its virulence compared to that of the parent by intraperitoneal injection into mice. The lethality of the parent strain was found higher than that of the cured strain. With a sublethal number of cells of the parent strain injected, the spleen, liver and lymph nodes in various sites were markedly enlarged, and the bacteria were isolated from the heart blood. In contrast to this, neither enlargement of the organs nor recovery of organisms was observed with the cured strain. The Tn1-tagged 50 kb plasmid was next introduced by transformation into the cured strain. The virulence of the plasmid-reintroduced strain was higher than that of the cured strain, and in fact identical to that of the parent. We conclude that the 50 kb plasmid of S. choleraesuis is closely related with the mouse virulence of the organism.
在研究的所有6株猪霍乱沙门氏菌中均发现了一个50千碱基（kb）的质粒，这些菌株最初从患败血症的猪或人体中分离得到。用新生霉素处理后，分离出了不含50 kb质粒的衍生物，并通过腹腔注射到小鼠体内，将其毒力与亲本菌株进行比较。结果发现亲本菌株的致死率高于治愈菌株。注射亚致死数量的亲本菌株细胞后，脾脏、肝脏和不同部位的淋巴结明显肿大，且从心血中分离出了细菌。与此形成对比的是，治愈菌株既未观察到器官肿大，也未分离到细菌。接下来，通过转化将带有Tn1标签的50 kb质粒导入治愈菌株。重新导入质粒的菌株的毒力高于治愈菌株，实际上与亲本菌株相同。我们得出结论，猪霍乱沙门氏菌的50 kb质粒与该菌对小鼠的毒力密切相关。
