Clinical and Diagnostic Laboratory Immunology, May 1998, p. 299-302, Vol. 5, No. 3
1071-412X/98/$00.00+0
Enteric Diseases and Food Safety Research Unit, National Animal Disease Center, USDA Agricultural Research Service, Ames, Iowa 50010
Received 21 July 1997/Returned for modification 11 November 1997/Accepted 21 January 1998
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.
Present address: Department of Surgery, College of Medicine,
University of Louisville, Louisville, KY 40292.
| Antimicrob. Agents Chemother. | Clin. Microbiol. Rev. | Infect. Immun. |
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