Characterization and immuno-detection of AIDA-I adhesin isolated from porcine Escherichia coli.
A relatively high percentage of porcine Escherichia coli isolates from cases associated with neonatal and post-weaning diarrhea are positive for the gene encoding adhesin involved in diffuse adhesion I (AIDA-I). This gene and its corresponding protein were first identified and characterized in E. coli strain 2787 isolated from human infantile diarrhea. Little is known about the properties of the AIDA-I protein and its immuno-detection on surface of AIDA-I positive porcine E. coli isolates. In this study, we demonstrated that the AIDA-I adhesin isolated from porcine AIDA-I positive E. coli is an acidic protein consisting of five isoforms. It has a similar molecular weight (100 kDa) and relatively high amino acid homology (78-87%) with the AIDA-I adhesin expressed by human AIDA-I positive E. coli strain 2787. Based on limited comparison, it appears that there is a very high homology among AIDA-I proteins expressed by porcine AIDA-I positive E. coli isolates. Sensitivity of detection of surface AIDA-I adhesin of PCR-positive AIDA-I E. coli by immuno-dot-blot and coagglutination tests was 76 and 71%, respectively, whereas specificity was 89 and 84%, respectively. These tests are unlikely to be used for diagnostic detection of AIDA-I positive E. coli due to the relatively low sensitivity; however, they may be potentially useful for identification of false positive reactions generated by other diagnostic tests.
Fang
Y
Y
Department of Veterinary Pathology, Western Collage of Veterinary Medicine, University of Saskatchewan, 52 Campus Dr., Saskatoon, Sask., Canada S7N 5B4.
Ngeleka
M
M
Middleton
D M
DM
Simko
E
E
D018830:Adhesins, Escherichia coli / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D000372:Agglutination Tests / Q000662:veterinary; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D015180:Electrophoresis, Gel, Two-Dimensional / Q000662:veterinary; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D004926:Escherichia coli / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D020033:Protein Isoforms; D012680:Sensitivity and Specificity; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D013552:Swine; D013553:Swine Diseases / Q000276:immunology / Q000382:microbiology*
C075559:AIDA-I protein, E coli; D018830:Adhesins, Escherichia coli; D020033:Protein Isoforms