Nakao H, Pruckler J M, Mazurova I K, Narvskaia O V, Glushkevich T, Marijevski V F, Kravetz A N, Fields B S, Wachsmuth I K, Popovic T
Division of Bacterial and Mycotic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
J Clin Microbiol. 1996 Jul;34(7):1711-6. doi: 10.1128/JCM.34.7.1711-1716.1996.
Diphtheria toxin (tox) and its regulatory element (dtxR) from 72 Corynebacterium diphtheriae strains isolated in Russia and Ukraine before and during the current diphtheria epidemic were studied by PCR-single-strand conformation polymorphism analysis (PCR-SSCP). Twelve sets of primers were constructed (eight for tox and four for dtxR), and three regions within tox and all four regions of dtxR showed significant variations in the number and/or sizes of the amplicons. Two to four different SSCP patterns were identified in each of the variable regions; subsequently, tox and dtxR could be classified into 6 and 12 different types, respectively. The great majority of epidemic strains from both Russia and Ukraine had tox types 3 and 4, and only in a single preepidemic strain isolated in Russia were all eight tox regions identical to those of C. diphtheriae Park-Williams No. 8 (tox type 1). Epidemic strains from Ukraine can easily be identified by dtxR type 5, while the majority of the Russian epidemic strains have dtxR of types 2 and 8. No differences in the tox regions between mitis and gravis biotype strains were observed. However, dtxR types 2, 5, and 8 were identified only in the gravis biotype, and dtxR type 1 was characteristic for the mitis biotype strains. PCR-SSCP is a simple and rapid method for the identification of variable tox and dtxR regions that allows for the clear association of tox and dtxR types with strains of distinct temporal and/or geographic origins.
采用聚合酶链反应-单链构象多态性分析（PCR-SSCP）对俄罗斯和乌克兰在当前白喉流行之前及流行期间分离出的72株白喉棒状杆菌菌株的白喉毒素（tox）及其调控元件（dtxR）进行了研究。构建了12组引物（8组用于tox，4组用于dtxR），tox内的3个区域以及dtxR的所有4个区域在扩增子数量和/或大小上显示出显著差异。在每个可变区域中鉴定出2至4种不同的SSCP模式；随后，tox和dtxR可分别分为6种和12种不同类型。来自俄罗斯和乌克兰的绝大多数流行菌株具有tox 3型和4型，仅在俄罗斯分离出的一株流行前菌株中，所有8个tox区域与白喉棒状杆菌Park-Williams No. 8的区域相同（tox 1型）。乌克兰的流行菌株可通过dtxR 5型轻松鉴定，而大多数俄罗斯流行菌株具有dtxR 2型和8型。在轻型和重型生物型菌株之间未观察到tox区域的差异。然而，dtxR 2型、5型和8型仅在重型生物型中鉴定出，dtxR 1型是轻型生物型菌株的特征。PCR-SSCP是一种用于鉴定tox和dtxR可变区域的简单快速方法，它能够将tox和dtxR类型与不同时间和/或地理来源的菌株明确关联起来。
