Prevalence and characterization of virulence genes in Escherichia coli isolated from piglets suffering post‐weaning diarrhoea in Shandong Province, China

Abstract The present study was performed to investigate the prevalence and characteristics of virulence genes in Escherichia coli (E. coli) isolated from piglets suffering post‐weaning diarrhoea (PWD) in Shandong Province, China. The standard bacteriological method was used to isolate and identify E. coli, and then multiplex polymerase chain reaction (mPCR) was performed to determine virulence genes in E. coli. Among the 300 isolates, 166 (55.3％) harboured at least one virulence gene. Among the 166 isolates, 155 (93.4％) contained toxin‐related genes. For enterotoxin genes, EAST1 (58/166, 34.9％) and LT‐I (45/166, 27.1％) were the most common, followed by STa (32/166, 19.3％) and STb (21/166, 12.7％); for pathogenicity island (PAI) genes, irp2 (49/166, 29.5％) was the most dominant, followed by eae (48/166, 28.9％); for Shiga toxigenic E. coli (STEC)‐associated toxin genes, Stx2e and hlyA genes were observed in 19 (19/166, 11.4％) and three strains (3/166, 1.8％) respectively. In addition, of the 166 isolates, 95 (95/166, 57.2％) contained adhesin genes, and AIDA‐I (33/166, 19.9％) was the most common, followed by paa (27/166, 16.3％), F5 (K99) (20/166, 12.0％), F18 (15/166, 9.0％) and F41 (12/166, 7.2％). In summary, these findings demonstrated the prevalence and characteristics of virulence factors in E. coli isolates from piglets with PWD in Shandong Province of China, and the data may be useful for establishing preventive measures for post‐weaning piglet diarrhoea.