Comparison of sorbitol MacConkey agar and a two-step method which utilizes enzyme-linked immunosorbent assay toxin testing and a chromogenic agar to detect and isolate enterohemorrhagic Escherichia coli
Comparison of sorbitol MacConkey agar and a two-step method which utilizes enzyme-linked immunosorbent assay toxin testing and a chromogenic agar to detect and isolate enterohemorrhagic Escherichia coli
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DOI：
10.1128/jcm.38.2.547-551.2000
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发表时间：
2000-02-01
影响因子：
9.4
通讯作者：
Carroll, KC
中科院分区：
文献类型：
--
作者：
Novicki, TJ;Daly, JA;Carroll, KC
肠出血性大肠杆菌（EHEC），特别是血清型O157:H7是出血性胃肠道疾病和溶血性尿毒症综合征的重要病因。目前临床微生物实验室使用的方法，如山梨糖醇-麦康基（SMAC）琼脂，只能可靠地检测O157:H7。我们已经评估了一种两步法，该方法有可能识别和分离所有肠出血性大肠杆菌血清型，包括血清型O157:H7。该方法利用显色选择性鉴别培养基分离大肠杆菌，并采用酶联免疫吸附试验（ELISA）检测志贺样毒素Stx1和Stx2。两者都是市售的，可用于广泛的临床微生物实验室。与Vero细胞毒性试验相比，SMAC对所有肠出血性大肠杆菌血清型的敏感性为23.5%，对O157:H7血清型的敏感性为50.0%。两步法的灵敏度分别为76.5和100%。单独ELISA检测Stx1和Stx2的灵敏度为82.4%。所有病例特异性均为100%。共分离出14株肠出血性大肠杆菌：8株（58%）O157:H7, 2株（14%）O26, 2株（14%）O111:NM， 1株（7%）O103: H2, 1株（7%）O121:H19。在5月至9月期间，除一人外，其他所有人都被隔离。对于阳性和阴性样品，两步法都比SMAC法昂贵得多。
Enterohemorrhagic Escherichia coli (EHEC) and specifically serotype O157:H7 are a significant cause of hemorrhagic gastrointestinal disease and the hemolytic uremic syndrome. Methods currently used in clinical microbiology labs, such as sorbitol-MacConkey (SMAC) agar, reliably detect only O157:H7. We have evaluated a two-step method that has the potential to identify and isolate all EHEC serotypes, including serotype O157:H7. This method utilizes a chromogenic selective-differential medium for the isolation of E. coli together with an enzyme-linked immunosorbent assay (ELISA) that detects the Shiga-like toxins Stx1 and Stx2. Both are commercially available and usable in a wide range of clinical microbiology laboratories. Compared to a Vero cell cytotoxic assay, SMAC had sensitivities of 23.5% for the identification of all EHEC serotypes and of 50.0% for the identification of O157:H7 alone. The two-step method had sensitivities of 76.5 and 100%, respectively. The ELISA alone had a sensitivity of 82.4% in the detection of Stx1 and Stx2. The specificity was 100% in all cases. Overall, 14 EHEC isolates were obtained: 8 (58%) O157:H7, 2 (14%) O26, 2 (14%) O111:NM, 1 (7%) O103: H2, and 1 (7%) O121:H19. All but one were isolated during the months of May to September. The tao-step method was found to be considerably more expensive than SMAC for both positive and negative samples.