Profiles of virulence genes in enterotoxigenic Escherichia coli isolates from suckling piglets in Serbia

A total of 120 Escherichia coli (E. coli) strains from suckling piglets with diarrhoea and 30 E. coli strains from healthy piglets were tested for the presence of fimbrial and enterotoxin virulence genes. Out of the 120 isolates sampled from diarrheic piglets, 81 (67.5%) expressed one or more genes encoding virulence factors. Adhesin genes were detected in 52 (43.33%) out of 120 E. coli isolates, and the most common among them was F4 adhesin (33.33%). Genes encoding E. coli toxins were detected in 81 (67.5%) isolates. E. coli included in the study carried genes for one or more of the following toxins: STa, STb, LT and EAST1. The astA gene encoding EAST1 was the most prevalent and was identified in 72 (60%) E. coli isolates. EAST1 toxin was detected in 5 out of 30 isolates (16.7%) from healthy piglets. Among the 81 isolates expressing virulence genes, a total of 15 different combinations for fimbrial and toxin genes were found. The most common virulence pattern was F4/STb/LT/EAST1 detected in 23.45% of E. coli strains isolated from suckling piglets with diarrhoea. The results indicate that F4 adhesin and EAST1 toxin are the most common in E. coli isolates sampled from diarrhoeic suckling piglets in Serbia.