Thong K L, Cheong Y M, Puthucheary S, Koh C L, Pang T
Department of Medical Microbiology, University of Malaya, Kuala Lumpur, Malaysia.
J Clin Microbiol. 1994 May;32(5):1135-41. doi: 10.1128/jcm.32.5.1135-1141.1994.
Pulsed-field gel electrophoresis (PFGE) was used to compare and analyze 158 isolates of Salmonella typhi from five well-defined outbreaks of typhoid fever in Malaysia and also isolates involved in sporadic cases of typhoid fever occurring during the same period. Digestion of chromosomal DNAs from these S. typhi isolates with the restriction endonucleases XbaI (5'-TCTAGA-3'), SpeI (5'-ACTAGT-3'), and AvrII (5'-CCTAGG-3') and then PFGE produced restriction endonuclease analysis (REA) patterns consisting of 11 to 24 DNA fragments ranging in size from 20 to 630 kbp. Analysis of the REA patterns generated by PFGE after digestion with XbaI and SpeI indicated that the S. typhi isolates obtained from sporadic cases of infection were much more heterogeneous (at least 13 different REA patterns were detected; Dice coefficient, between 0.73 and 1.0) than those obtained during outbreaks of typhoid fever. The clonal nature and the close genetic identities of isolates from outbreaks in Alor Setar, Penang, Kota Kinabalu, Johor Bahru, and Kota Bahru were suggested by the fact that only a limited number of REA patterns, which mostly differed by only a single band, were detected (one to four patterns; Dice coefficient, between 0.82 and 1.0), although a different pattern was associated with each of these outbreaks. Comparison of REA patterns with ribotyping for 18 S. typhi isolates involved in sporadic cases of infection showed a good correlation, in that 72% of the isolates were in the same group. There was no clear correlation of phage types with a specific REA pattern. We conclude that PFGE of s. typhi chromosomal DNA digested with infrequently cutting restriction endonucleases is a useful method for comparing and differentiating S. typhi isolates for epidemiological purposes.
脉冲场凝胶电泳（PFGE）用于比较和分析从马来西亚五起明确界定的伤寒热暴发中分离出的158株伤寒沙门氏菌，以及同期发生的散发性伤寒热病例中涉及的分离株。用限制性内切酶XbaI（5'-TCTAGA-3'）、SpeI（5'-ACTAGT-3'）和AvrII（5'-CCTAGG-3'）消化这些伤寒沙门氏菌分离株的染色体DNA，然后进行PFGE，产生了由11至24个DNA片段组成的限制性内切酶分析（REA）图谱，片段大小在20至630kbp之间。对用XbaI和SpeI消化后由PFGE产生的REA图谱分析表明，从散发性感染病例中获得的伤寒沙门氏菌分离株比在伤寒热暴发期间获得的分离株具有更高的异质性（至少检测到13种不同的REA图谱；戴斯系数在0.73至1.0之间）。在亚罗士打、槟城、哥打基纳巴卢、新山和哥打巴鲁暴发中分离株的克隆性质和密切的遗传相似性表明，尽管这些暴发中的每一次都与不同的图谱相关，但仅检测到数量有限的REA图谱（一至四种图谱；戴斯系数在0.82至1.0之间），这些图谱大多仅相差一条带。对18株涉及散发性感染病例的伤寒沙门氏菌分离株的REA图谱与核糖体分型进行比较，结果显示有良好的相关性，因为72%的分离株属于同一组。噬菌体类型与特定的REA图谱之间没有明显的相关性。我们得出结论，用不常用的限制性内切酶消化伤寒沙门氏菌染色体DNA进行PFGE是用于流行病学目的比较和区分伤寒沙门氏菌分离株的有用方法。
