Pathotype and virulence genes of diarrheogenic Escherichia coli isolated from pig farms

Abstract

Objective To investigate the distribution of virulence genes and pathotypes of diarrheogenic Escherichia coli(DEC) from commercial pig farms, providing reference data for prevention and control of foodborne diseases caused by the bacteria from the pork production industry. Methods The virulence genes of Escherichia coli(E. coli), isolated from 12 pig farms, were detected by multiplex real-time quantitative polymerase chain reaction(PCR). Results Among 985 E. coli isolated from pig farms, DEC accounted for 28.83%(284/985), including 225 enteroaggregative E. coli (EAEC, 22.84%, 225/985), 14 enterotoxigenic E. coli (ETEC, 1.42%, 14/985), 12 enteropathogenic E. coli (EPEC, 1.22%, 12/985), 10 enterohemorrhagic E. coli (EHEC, 1.02%, 10/985), 9 enteroinvasive E. coli (EIEC, 0.91%, 9/985), 13 hybrid EHEC-ETEC(1.32%, 13/985), and 1 hybrid EPEC-ETEC(0.10%, 1/985). Among all those strains, one from the nose swab of a breeder had the same EHEC-ETEC virulence genotype as those positive samples detected in pig nose swab and feces. It was also found that the contamination rate of DEC in early fattening stage was significantly higher than that in late fattening stage(χ2=1.10, P<0.05). Conclusion The contamination rate of DEC in pig farms was high. It is suggested that we should strengthen the detection of pathogenic bacteria in pig farms, prevent and control the DEC contamination from the source of breeding in pigs, and reduce the occurrence of foodborne diseases and zoonoses.

Keywords

• pig farm
• diarrheogenic escherichia coli
• virulence gene
• pathotype