Heterogeneity of Escherichia coli STb enterotoxin isolated from diseased pigs.
To investigate the presence and frequency of estB variant(s), a collection of 100 STb-positive enterotoxigenic Escherichia coli (ETEC) strains isolated from 1980 to 2007 inclusively and randomly selected from diseased pigs in Québec, Canada, was analysed. A wide diversity of virulence gene profiles (virotypes) was detected in the strain collection. The estB gene was amplified by PCR using primers designed from the signal sequence and the C-terminal end, and the amplified fragment was sequenced using the forward primer. The translated DNA sequence revealed a His(12)-->Asn change in 23 of the 100 ETEC isolates tested. The STb-variant strains were observed throughout the sampling period covered in the study. No other STb-variant type was found in this study. All 23 variant strains were also positive for the STa enterotoxin and were resistant to tetracycline, as for strain 2173. The STb variant was associated with Stx2-positive strains (5/6) and STa : STb strains that did not harbour any of the tested porcine fimbrial adhesins (13/17). The remaining variant strains were associated with fimbriae F4 (1/40), F5 (1/6), F6 (1/1) and F18 (2/7; excluding F18 : Stx2 strains).
Taillon
Christine
C
Centre de Recherche en Infectiologie Porcine (CRIP), Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC J2S 7C6, Canada.
Nadeau
Eric
E
Centre de Recherche en Infectiologie Porcine (CRIP), Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC J2S 7C6, Canada.
Mourez
Michaël
M
Centre de Recherche en Infectiologie Porcine (CRIP), Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC J2S 7C6, Canada.
Dubreuil
J Daniel
JD
Centre de Recherche en Infectiologie Porcine (CRIP), Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC J2S 7C6, Canada.
D000818:Animals; D001427:Bacterial Toxins / Q000145:classification / Q000235:genetics*; D054307:Enterotoxigenic Escherichia coli / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D004768:Enterotoxins / Q000145:classification / Q000235:genetics*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D029968:Escherichia coli Proteins / Q000235:genetics; D014644:Genetic Variation; D016133:Polymerase Chain Reaction; D011792:Quebec; D017422:Sequence Analysis, DNA; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology*; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics
D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D037521:Virulence Factors; C034151:heat stable toxin (E coli)