Frankel G, Riley L, Giron J A, Valmassoi J, Friedmann A, Strockbine N, Falkow S, Schoolnik G K
Department of Microbiology, Stanford University, CA 94305.
J Infect Dis. 1990 Jun;161(6):1252-6. doi: 10.1093/infdis/161.6.1252.
A rapid diagnostic method employing a polymerase chain reaction procedure (PCR) was used to identify Shigella and enteroinvasive Escherichia coli. This procedure amplified a region of the invasive-associated locus (ial) from a crude DNA extract of feces. A synthetic 21-base oligonucleotide corresponding to the ial gene sequence was shown to specifically hybridize only with enteroinvasive E. coli (EIEC) strains and Shigella species. Upon PCR amplification, a 320-base pair fragment was generated in DNA extracted from feces reconstituted with EIEC or Shigella flexneri but not in DNA from 70 normal stools lacking these organisms and could be readily detected by the ial probe. For identifying Shigella and EIEC, the PCR assay was 10(5)- and 10(2)-fold more sensitive than standard biochemical tests and the macrocolony hybridization assay, respectively. These findings demonstrate a novel methodology for rapid, sensitive, and culture-independent diagnosis of diarrhea caused by these pathogens and underscores the utility of PCR in the diagnostic laboratory.
一种采用聚合酶链反应程序（PCR）的快速诊断方法被用于鉴定志贺氏菌和肠侵袭性大肠杆菌。该程序从粪便的粗DNA提取物中扩增侵袭相关基因座（ial）的一个区域。一条与ial基因序列对应的21个碱基的合成寡核苷酸被证明仅与肠侵袭性大肠杆菌（EIEC）菌株和志贺氏菌属特异性杂交。经过PCR扩增，在用EIEC或福氏志贺氏菌重构的粪便中提取的DNA中产生了一个320碱基对的片段，但在缺乏这些微生物的70份正常粪便的DNA中未产生，并且可以很容易地被ial探针检测到。对于鉴定志贺氏菌和EIEC，PCR检测分别比标准生化试验和大菌落杂交试验敏感10^5倍和10^2倍。这些发现证明了一种用于快速、灵敏且不依赖培养诊断由这些病原体引起的腹泻的新方法，并强调了PCR在诊断实验室中的实用性。
