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标题：Escherichia coli O-Antigen Gene Clusters of Serogroups O62, O68, O131, O140, O142, and O163: DNA Sequences and Similarity between O62 and O68, and PCR-Based Serogrouping
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作者：Yanhong Liu ; Xianghe Yan
期刊名称：Biosensors
电子版ISSN：2079-6374
出版年度：2015
卷号：5
期号：1
页码：51-68
DOI：10.3390/bios5010051
语种：English
出版社：MDPI Publishing
摘要：The DNA sequence of the O-antigen gene clusters of Escherichia coli serogroups O62, O68, O131, O140, O142, and O163 was determined, and primers based on the wzx (O-antigen flippase) and/or wzy (O-antigen polymerase) genes within the O-antigen gene clusters were designed and used in PCR assays to identify each serogroup. Specificity was tested with E. coli reference strains, field isolates belonging to the target serogroups, and non-E. coli bacteria. The PCR assays were highly specific for the respective serogroups; however, the PCR assay targeting the O62 wzx gene reacted positively with strains belonging to E. coli O68, which was determined by serotyping. Analysis of the O-antigen gene cluster sequences of serogroups O62 and O68 reference strains showed that they were 94% identical at the nucleotide level, although O62 contained an insertion sequence (IS) element located between the rmlA and rmlC genes within the O-antigen gene cluster. A PCR assay targeting the rmlA and rmlC genes flanking the IS element was used to differentiate O62 and O68 serogroups. The PCR assays developed in this study can be used for the detection and identification of E. coli O62/O68, O131, O140, O142, and O163 strains isolated from different sources.
关键词：PCR; Escherichia coli ; serogroups; DNA sequence; O-antigen gene cluster; detection; identification PCR ; Escherichia coli ; serogroups ; DNA sequence ; O-antigen gene cluster ; detection ; identification