Sato G, Terakado N
Am J Vet Res. 1977 Jun;38(6):743-7.
Typing of R factors by genetic properties was done with Salmonella typhimurium and Escherichia coli isolated from calves on a feedlot where epizootics of clinical or subclinical calf salmonellosis had repeatedly occurred during 5 years. Forty-nine R factors from S typhimurium were fi- (no fertility inhibition) and spp- (no restriction against phage lambda vir). Twenty-three (46.9%) of them belonged to compatibility group Ialpha and the remainder were nontypable. Fourteen R factors from E coli belonged to different genetic types: fi+ (11=78.6%) and fi- (3=21.4%); spp+ (1=7.1%) and spp- (13=92.9%); compatibility groups FII (5=35.7%), N (1=7.1%), and nontypable (8=57.2%). In contrast to the R factors of S typhimurium, 9 (64.3%) of the 14 R factors of E coli carried resistance against aminobenzyl penicillin with or without kanamycin resistance. The compatibility groups of R factors of S typhimurium seemed to be useful as a subsidiary epizootiologic marker in this feedlot.
利用从一个育肥牛场的犊牛中分离出的鼠伤寒沙门氏菌和大肠杆菌，通过遗传特性对R因子进行分型。该育肥牛场在5年期间反复发生临床或亚临床犊牛沙门氏菌病的流行。从鼠伤寒沙门氏菌中分离出的49个R因子为fi-（无育性抑制）和spp-（对λ噬菌体病毒无限制）。其中23个（46.9%）属于相容性群Iα，其余无法分型。从大肠杆菌中分离出的14个R因子属于不同的遗传类型：fi+（11个，占78.6%）和fi-（3个，占21.4%）；spp+（1个，占7.1%）和spp-（13个，占92.9%）；相容性群FII（5个，占35.7%）、N（1个，占7.1%），以及无法分型（8个，占57.2%）。与鼠伤寒沙门氏菌的R因子不同，大肠杆菌的14个R因子中有9个（64.3%）携带对氨苄青霉素的耐药性，有的还伴有对卡那霉素的耐药性。在这个育肥牛场中，鼠伤寒沙门氏菌R因子的相容性群似乎可作为一种辅助的动物流行病学标记。
