Venkatesan M M, Buysse J M, Kopecko D J
Department of Bacterial Immunology, Walter Reed Army Medical Center, Washington, D.C. 20307-5100.
J Clin Microbiol. 1989 Dec;27(12):2687-91. doi: 10.1128/jcm.27.12.2687-2691.1989.
The products of the ipaB, ipaC, and ipaD genes are involved in the expression of the invasive phenotype in all species of Shigella and enteroinvasive Escherichia coli (EIEC). DNA probes derived from these genes are accurate indicators of the invasive phenotype (M. Venkatesan, J. M. Buysse, E. V. Vandendries, and D. J. Kopecko, J. Clin. Microbiol. 26:261-266, 1988); however, spontaneous loss of the invasion plasmid or selective deletion of invasion-associated genes may restrict the usefulness of such probes as general diagnostic tools. In this study, we report that laboratory-passaged strains of Shigella spp. and EIEC that were invasion and Sereny test negative were unable to hybridize to the ipaC DNA probe. However, a second DNA probe, derived from the Shigella flexneri ipaH gene, a multiple-copy element found on the chromosome and invasion plasmid that encodes a 60-kilodalton antigen, was more sensitive in its ability to detect virulent as well as avirulent shigellae and EIEC. Analysis of colony blots and stool blots from pediatric patients with diarrhea indicated that the ipaH probe was more effective in detecting shigellae and EIEC than was either the ipaC or 17-kilobase EcoRI fragment probe.
ipaB、ipaC和ipaD基因的产物参与所有志贺氏菌属和肠侵袭性大肠杆菌（EIEC）侵袭性表型的表达。源自这些基因的DNA探针是侵袭性表型的准确指标（M. 文卡特桑、J. M. 布伊斯、E. V. 万登德里和D. J. 科普科，《临床微生物学杂志》26:261 - 266，1988年）；然而，侵袭性质粒的自发丢失或侵袭相关基因的选择性缺失可能会限制此类探针作为一般诊断工具的实用性。在本研究中，我们报告说，实验室传代的志贺氏菌属菌株和EIEC菌株，若侵袭试验和塞雷尼试验呈阴性，则无法与ipaC DNA探针杂交。然而，另一种DNA探针，源自弗氏志贺氏菌ipaH基因，该基因是在染色体和侵袭性质粒上发现的多拷贝元件，编码一种60千道尔顿的抗原，在检测有毒和无毒志贺氏菌及EIEC方面更具敏感性。对腹泻儿科患者的菌落印迹和粪便印迹分析表明，ipaH探针在检测志贺氏菌和EIEC方面比ipaC或17千碱基EcoRI片段探针更有效。
