Toth I, Barrett T J, Cohen M L, Rumschlag H S, Green J H, Wachsmuth I K
National Institute of Hygiene, Budapest, Hungary.
J Clin Microbiol. 1991 May;29(5):1016-9. doi: 10.1128/jcm.29.5.1016-1019.1991.
Eighty strains of pathogenic Escherichia coli, representing each of the major diarrheal disease-causing groups, were examined by direct enzyme-linked immunosorbent assay (ELISA) for the presence of proteins associated with a 60-MDa plasmid from E. coli serotype O157:H7. Antiserum specific for plasmid-encoded proteins was prepared by immunizing a rabbit with a wild-type E. coli O157:H7 strain (strain 7785) and absorbing the serum with a plasmid-cured derivative (strain 2-45). Use of this antiserum in Western immunoblot analysis detected two proteins of 82 and 92 kDa in strain 7785 but not in strain 2-45. All 16 wild-type E. coli O157:H7 strains and all 10 Shiga-like toxin (SLT)-producing E. coli strains of serotypes other than O157 were ELISA positive. Thirteen of 14 enterotoxigenic and all of 24 enteroinvasive E. coli strains were ELISA negative, as were all of 16 E. coli strains isolated from healthy persons. Of 16 traditional enteropathogenic E. coli (EPEC) serotypes, 10 were ELISA positive, including 10 of 12 strains carrying the EPEC adherence factor gene. Absorption of the serum with an EPEC adherence factor-positive EPEC eliminated EPEC reactivity. This study demonstrates that two plasmid-mediated proteins are common to E. coli O157:H7 strains and to SLT-producing strains of other serotypes. Detection of these proteins by ELISA provides a sensitive and specific screening test for identifying SLT-producing E. coli of both O157 and non-O157 serotypes. Identification of the cross-reactive proteins found in EPEC could provide the basis for a single assay to detect both EPEC and SLT-producing E. coli.
采用直接酶联免疫吸附测定法（ELISA），对代表各主要致腹泻病致病菌群的80株致病性大肠杆菌进行检测，以确定是否存在与大肠杆菌O157:H7血清型60兆道尔顿质粒相关的蛋白质。通过用野生型大肠杆菌O157:H7菌株（7785株）免疫兔子，并用质粒消除衍生物（2-45株）吸收血清，制备了针对质粒编码蛋白的抗血清。在蛋白质免疫印迹分析中使用该抗血清，在7785株中检测到82和92千道尔顿的两种蛋白质，而在2-45株中未检测到。所有16株野生型大肠杆菌O157:H7菌株和所有10株非O157血清型的产志贺样毒素（SLT）大肠杆菌菌株ELISA检测均为阳性。14株产肠毒素大肠杆菌中的13株以及24株侵袭性大肠杆菌全部ELISA检测为阴性，从健康人分离出的16株大肠杆菌也均为阴性。16种传统致病性大肠杆菌（EPEC）血清型中，10种ELISA检测为阳性，包括12株携带EPEC黏附因子基因的菌株中的10株。用EPEC黏附因子阳性的EPEC吸收血清可消除EPEC反应性。本研究表明，两种质粒介导的蛋白质在大肠杆菌O157:H7菌株和其他血清型的产SLT菌株中很常见。通过ELISA检测这些蛋白质可为鉴定O157和非O157血清型的产SLT大肠杆菌提供一种灵敏且特异的筛选试验。鉴定EPEC中发现的交叉反应蛋白可为同时检测EPEC和产SLT大肠杆菌的单一检测方法提供依据。
