用于检测和鉴定大肠杆菌中维罗毒素（志贺毒素）的微孔板乳胶凝集法（Verotox - F检测法）的评估。
Evaluation of a microplate latex agglutination method (Verotox-F assay) for detecting and characterizing verotoxins (Shiga toxins) in Escherichia coli.
作者信息
Karmali M A, Petric M, Bielaszewska M
机构信息
Research Institute and Division of Microbiology, Department of Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8.
出版信息
J Clin Microbiol. 1999 Feb;37(2):396-9. doi: 10.1128/JCM.37.2.396-399.1999.
The performance of a commercial microplate latex agglutination assay, the Verotox-F assay, was compared with that of the Vero cell assay for the detection and characterization of Escherichia coli verocytotoxins (VTs). Culture filtrates of 68 VT-positive E. coli strains (65 human isolates [33 of serotype O157:H7/H-, 32 of non-O157 serotypes] and 3 reference strains) and 104 VT-negative strains (100 human isolates and 4 reference strains) were investigated. The toxin phenotypes and genotypes of the 68 VT-positive isolates were VT1 only (18 strains), VT2 and/or VT2c (33 strains), and VT1 plus VT2 (17 strains). The Verotox-F assay involved incubation of serial dilutions of culture filtrates with equal volumes of latex particles sensitized with anti-VT1 antibody or anti-VT2 antibody in 96-well microtiter plates with appropriate controls and examination for latex agglutination after 20 to 24 h. Compared to the results of the Vero cell assay, the Verotox-F assay was 100% sensitive and 100% specific for the detection of VTs in culture filtrates and correctly identified the toxin types of all 68 VT producers. By checkerboard titration with purified toxins, the sensitivity of the Verotox-F assay was found to be 14 pg (0.7 ng/ml) for VT1, 12 pg (0.6 ng/ml) for VT2, and 350 pg (17.5 ng/ml) for VT2c; this sensitivity is comparable to that of the bioassay. The anti-VT2 latex reagent detected both VT2 and VT2c and did not cross-react with VT1. The anti-VT1 reagent showed a low-level cross-reaction with VT2c only at levels (>/=4.5 microg/ml) that were about 1,000-fold higher than those found in culture filtrates. We conclude that the Verotox-F assay is highly sensitive and specific for the detection and characterization of VTs in culture filtrates of human E. coli isolates. The test is rapid, reliable, and easy to perform; its results are easy to interpret; and it should allow testing for VT to become more widely performed.
将一种商业微孔板乳胶凝集试验（Verotox - F试验）与Vero细胞试验的性能进行了比较，以检测和鉴定大肠杆菌志贺毒素（VTs）。对68株产VT的大肠杆菌菌株（65株临床分离株[33株O157:H7/H-血清型，32株非O157血清型]和3株参考菌株）以及104株不产VT的菌株（100株临床分离株和4株参考菌株）的培养滤液进行了研究。68株产VT的分离株的毒素表型和基因型分别为仅VT1（18株）、VT2和/或VT2c（33株）以及VT1加VT2（17株）。Verotox - F试验包括在96孔微量滴定板中将培养滤液的系列稀释液与等体积的用抗VT1抗体或抗VT2抗体致敏的乳胶颗粒一起孵育，并设置适当的对照，20至24小时后检查乳胶凝集情况。与Vero细胞试验的结果相比，Verotox - F试验在检测培养滤液中的VTs时灵敏度和特异性均为100%，并且正确鉴定了所有68株产VT菌株的毒素类型。通过用纯化毒素进行棋盘滴定，发现Verotox - F试验对VT1的灵敏度为14 pg（0.7 ng/ml），对VT2为12 pg（0.6 ng/ml），对VT2c为350 pg（17.5 ng/ml）；这种灵敏度与生物测定法相当。抗VT2乳胶试剂可检测VT2和VT2c，且不与VT1发生交叉反应。抗VT1试剂仅在浓度（≥4.5 μg/ml）比培养滤液中发现的浓度高约1000倍时才与VT2c发生低水平交叉反应。我们得出结论，Verotox - F试验在检测和鉴定人源大肠杆菌分离株培养滤液中的VTs时具有高度的灵敏度和特异性。该试验快速、可靠且易于操作；其结果易于解释；并且它应能使VT检测更广泛地开展。
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