Identification of virulence factors of enterotoxigenic Escherichia coli strains from calves via multiplex PCR

Enterotoxigenic Escherichia coli(ETEC) with virulence factors of K99 and/or F41 fimbriae and heat-stable enterotoxin a(STa) is a common pathogen causing diarrhea and acute enterotoxinemia in calves.Fast and reliable detection of the virulence factors is essential for identification and characterization of ETEC.A multiplex PCR method was developed to identify enterotoxigenic Escherichia coli strains by amplifying genes encoding K99 and F41 fimbriae,heat-stable enterotoxin.The parameters of PCR amplification,including concentration of dNTP,Mg2+,primers and annealing temperature were optimized.The specification and sensitivity of the multiplex PCR experiment were carried out on the basis of optimized parameters.It suggested that this multiplex PCR method was specific,sensitive and useful tool for identify ETEC strains from calves.