Litwin C M, Storm A L, Chipowsky S, Ryan K J
Department of Pathology, College of Medicine, University of Arizona, Tucson 85724.
J Clin Microbiol. 1991 Jan;29(1):104-8. doi: 10.1128/jcm.29.1.104-108.1991.
Plasmid isolation was used to refine the epidemiologic analysis for 168 shigellosis cases in Pima County, Ariz. Plasmids of less than 20 kb were used for comparison of plasmid profiles. Plasmid patterns for each species were distinct. A total of 57 of 74 (77%) Shigella flexneri strains could be placed into seven plasmid patterns, 70 of 79 (89%) Shigella sonnei strains could be placed into seven patterns, 12 Shigella boydii strains could be placed into six patterns, and each of 3 Shigella dysenteriae strains differed. There was a correlation between plasmid patterns and serotypes for S. flexneri, and multiple plasmid patterns were found in serotypes 1, 2, and 6, offering a refinement beyond serotyping. In previous studies we found an association between Mexican travel and an S. sonnei 5.1-kb plasmid. When this plasmid was used as a probe, strong homology was seen with numerous small plasmids in all Shigella species: restriction endonuclease analysis revealed a 1.1-kb AvaI-AvaII fragment common to various plasmids of S. sonnei. S. flexneri, and S. boydii independent of species. Of 34 Pima County Shigella isolates from the mid-1970s. 8 showed plasmid patterns similar to those of the recent isolates. Some plasmids from S. sonnei, S. flexneri, and S. boydii strains isolated in the 1970s also contained the AvaI-AvaII fragment. The conservation of this specific fragment in our population for more than 12 years suggests that it may contain genes important in virulence or survival.
采用质粒分离技术对亚利桑那州皮马县168例志贺氏菌病病例进行了流行病学分析。用小于20 kb的质粒比较质粒图谱。每种志贺氏菌的质粒图谱都不同。74株福氏志贺氏菌中有57株（77%）可分为7种质粒图谱类型，79株宋内氏志贺氏菌中有70株（89%）可分为7种类型，12株鲍氏志贺氏菌可分为6种类型，3株痢疾志贺氏菌各有不同。福氏志贺氏菌的质粒图谱与血清型之间存在相关性，在血清型1、2和6中发现了多种质粒图谱类型，这提供了超越血清分型的细化分析。在之前的研究中，我们发现前往墨西哥旅行与宋内氏志贺氏菌的5.1-kb质粒之间存在关联。当用该质粒作为探针时，在所有志贺氏菌属中都观察到与众多小质粒有很强的同源性：限制性内切酶分析显示，宋内氏志贺氏菌、福氏志贺氏菌和鲍氏志贺氏菌的各种质粒中都有一个1.1-kb的AvaI - AvaII片段，与物种无关。在皮马县20世纪70年代中期分离出的34株志贺氏菌中，有8株的质粒图谱与近期分离株相似。20世纪70年代分离出的一些宋内氏志贺氏菌、福氏志贺氏菌和鲍氏志贺氏菌菌株的质粒也含有AvaI - AvaII片段。该特定片段在我们的研究群体中12年多来一直保守存在，这表明它可能含有对毒力或生存至关重要的基因。
