Submitted to: Conference on Gastrointestinal Function
Publication Type: Abstract Only
Publication Acceptance Date: 3/12/2003
Publication Date: 3/12/2003
Citation: HELGERSON, A., SCHROEDER, R., SHARMA, V.K., POST, K., CORNICK, N.A. ESCHERICHIA COLI O147: AN EMERGING SEROGROUP OF EDEMA DISEASE OUTBREAKS. CONFERENCE ON GASTROINTESTINAL FUNCTION. 2003. V. 26. P. 21. Interpretive Summary:
Technical Abstract: Edema disease is a systemic disease of weanling pigs caused by E. coli strains that produce a variant of Shiga toxin, Stx2e. These strains usually produce F18ab fimbriae and heat stable enterotoxin b (STb). Historically, edema disease strains from U.S. outbreaks have not produced heat stable enterotoxin a (STa) and have belonged to the serogroups O138, O139 and O141. Many isolates recovered from recent outbreaks of edema disease have the sta gene and belong to the serogroup O147. We hypothesized that these strains may be an emerging clone of E. coli producing edema disease in the U.S. To test this hypothesis 51 E. coli O147 strains, isolated between 1996-2002, were compared to 5 E. coli O147 strains, isolated between 1970-1987, using pulsed-field gel electrophoresis (PFGE). The presence of virulence genes was confirmed using a multiplex PCR. The chromosomal DNA was cut with Xba I and subjected to the PFGE under standard conditions. GelComparII software was used to compare the banding patterns and determine relatedness. The majority of isolates (42/51) were positive on PCR for the genes f18, sta, stb, stx2e; and 7 isolates were positive for sta, stb, stx2e. Only one of the strains isolated prior to 1996 was positive for the gene profile f18, sta, stb, stx2e. PFGE divided the recent isolates into five distinct groups. More than half of the isolates (34/51) fell into a single group (A) with >90% similarity (DICE binary coefficient), 14 additional strains exhibited 85-90% similarity with group A and to one another. The three remaining strains were distinct from one another and from the other groups (<85% similarity). Our data suggests that many E. coli O147 strains that have a virulence genotype of f18, sta, stb, and stx2e are closely related to one another and may represent an emerging clone of E. coli producing edema disease in the U.S.