title: Characterization of Escherichia coli O3 and O21 O antigen gene clusters and development of serogroup-specific PCR assays.
abstract: Escherichia coli O3 and O21 are associated with enteroaggregative E. coli (EAEC). EAEC strains are often non-typable using the routine agglutination method due to their aggregative phenotype. Typing of E. coli O3 and O21 may also be impeded by cross-reactions with O152 or O83. In this study, the O antigen gene clusters of E. coli O3 and O21 were characterized, and PCR assays based on O antigen specific genes wzx (encoding O unit flippase) and wzy (encoding O unit polymerase) from each strain were developed. By screening against all 186 known E. coli O serotypes, the PCR assays were shown to be highly specific to O3 and O21 respectively. The sensitivity of the assays was determined to be 1 pg per microl of chromosomal DNA and 2 CFU per 10 g of water samples. The PCR assays were also applied to 658 clinical E. coli isolates, and 100% of detection accuracy was obtained. The PCR assays developed here are suitable for the detection and identification of E. coli O3 and O21 strains in environmental and clinical samples.
authors.affiliation: TEDA School of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin 300457, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Ren
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.forename: Jiansong
authors.initials: J
authors.lastname: Cheng
authors.forename: Fenxia
authors.initials: F
authors.lastname: Liu
authors.forename: Lu
authors.initials: L
authors.lastname: Feng
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
mesh_terms: D015373:Bacterial Typing Techniques; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics; D005798:Genes, Bacterial; D016695:Glycosyltransferases / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family; D019081:O Antigens / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D012703:Serotyping; D013997:Time Factors
chemical_list: D029968:Escherichia coli Proteins; D019081:O Antigens; D016695:Glycosyltransferases; C513753:Wzy polymerase, E coli