Beutin Lothar, Kong Qingke, Feng Lu, Wang Quan, Krause Gladys, Leomil Luciana, Jin Qi, Wang Lei
Division of Microbial Toxins,Robert Koch Institut, Nordufer 20, D-13353 Berlin, Germany.
J Clin Microbiol. 2005 Oct;43(10):5143-9. doi: 10.1128/JCM.43.10.5143-5149.2005.
Escherichia coli O 174 and O 177 are newly described O serogroups which were reported as human pathogens. Identification of these strains by serotyping has been restricted, as the required sera are not commercially available. In this study, a collection of 13 E. coli O 174 strains and 12 E. coli O 177 strains was studied on the O:H serotypes and virulence markers. The O-antigen gene clusters of E. coli O 174 and O 177 were sequenced, and associated genes were assigned functions on the basis of homology. Two genes, each specific for E. coli O 174 and O 177, were identified. PCR assays based on the O-antigen-specific genes were developed and tested on 25 clinical and environmental isolates of those two serogroups as well as 26 isolates of other O serogroups. As little as 1 pg per mul of chromosomal DNA and as few as 0.1 CFU per g of pork and water samples were detected for either strain. The PCR assays established in this study were shown to be highly sensitive and reliable and could be the method of choice for detection of these two human pathogens from clinical, food, and other environmental samples.
大肠埃希菌O174和O177是新描述的O血清群，已被报道为人类病原体。由于所需血清没有商业供应，通过血清分型鉴定这些菌株受到限制。在本研究中，对13株大肠埃希菌O174菌株和12株大肠埃希菌O177菌株进行了O:H血清型和毒力标记研究。对大肠埃希菌O174和O177的O抗原基因簇进行了测序，并根据同源性对相关基因进行了功能分配。鉴定出了分别对大肠埃希菌O174和O177特异的两个基因。基于O抗原特异性基因开发了PCR检测方法，并在这两个血清群的25株临床和环境分离株以及其他O血清群的26株分离株上进行了测试。对于任何一种菌株，每微升染色体DNA中低至1皮克以及每克猪肉和水样中低至0.1 CFU都能被检测到。本研究建立的PCR检测方法显示出高度灵敏和可靠，可能是从临床、食品和其他环境样本中检测这两种人类病原体的首选方法。
