Virulence genes of E.coli isolated from piglets with post-weaning diarrhea in Heilongjiang and their relationship with phylogenetic groups and O-serogroups

TONG Chun-yu,HU Rui,CUI Yu-dong*(College of Life Science and Technology,Heilongjiang Bayi Agricultural University,Daqing,Heilongjiang 163319,China)

post-weaning diarrhea(PWD);enterotoxigenic Escherichia coli(ETEC);serotypes;phylogenetic groups;enterotoxins

We determined the relationship of virulence genes with phylogenetic groups and O-serogroups Escherichia coli isolated from piglets with post-weaning diarrhea in Heilongjiang.123 E.coli isolates were serogrouped with O-antisera and detected for genes of enterotoxins STa,STb,LT and SLT-2e and phylogenetic markers of chuA,yjaA and TSPE4.C2 by PCR.The result showed that among 123 isolates,92 were placed in serogroups,21 were unable to be serogrouped,and the rest 10 auto-agglutinated.These isolates distributed in 18 serogroups and 61.96% belonged to 3 O-serogroups,O8,O9 and O149.91.87% of E.coli isolates belonged to group A and 1.63% to group D.Enterotoxigenic E.coli accounted for 74 and 60.16%,of which harbored the genes for the predominant enterotox was STa and STb,amounted to 94.59%,and pathogenic E.coli isolates collected from piglets with PWD of Heilongjiang province covered at least 18 O-serotypes and the predominant serotypes were O8,O9 and O149,predominant E.coli isolates belonged to phylogenetic group A,E.coli causing PWD were mostly enterotoxigenic with the predominant enterotoxins STa,STb.