title: Differentiation of F18ab+ from F18ac+ Escherichia coli by single-strand conformational polymorphism analysis of the major fimbrial subunit gene (fedA).
abstract: Toxin-producing Escherichia coli expressing F18 fimbriae colonizes the small intestines of weaned pigs and causes diarrhea, edema disease, or both. The F18 family is composed of two antigenic variants, F18ab and F18ac. Because many strains do not express F18 fimbriae in vitro, identification and differentiation of these two variants are difficult. Single-strand conformational polymorphism (SSCP) analysis is a rapid method for identifying genetic mutations and polymorphisms. The F18 major fimbrial subunit genes (fedA) of 138 strains were amplified by PCR, and genetic differences were detected by SSCP analysis. The SSCP analysis of the fedA gene differentiated F18ab+ strains from F18ac+ strains. Most strains classified as F18ab+ by SSCP analysis contained Shiga toxin 2e and enterotoxin genes. Most strains classified as F18ac+ by SSCP analysis contained only enterotoxin genes. The SSCP analysis was a useful method for predicting the antigenicity of F18+ E. coli and could also be used for analysis of other virulence genes in E. coli and other pathogenic bacteria.
authors.affiliation: Enteric Diseases and Food Safety Research Unit, National Animal Disease Center, USDA Agricultural Research Service, Ames, Iowa 50010, USA. bboswort@nadc.ars.usda.gov
authors.forename: B T
authors.initials: BT
authors.lastname: Bosworth
authors.forename: E A
authors.initials: EA
authors.lastname: Dean-Nystrom
authors.forename: T A
authors.initials: TA
authors.lastname: Casey
authors.forename: H L
authors.initials: HL
authors.lastname: Neibergs
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary; D029968:Escherichia coli Proteins; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000235:genetics*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C113053:FedA protein, E coli; D036781:Fimbriae Proteins