Hemolysins and verotoxin (VT) in enteric Escherichia coli isolated from pigs

One hundred and three E. coli strains isolated from the intestinal contents of pigs were examined for hemolysis and verotoxin production on Vero monolayer cells. Hemolysins were produced by 18 (17.5%) strains;--hemolysin was produced by 6 strains of which 4 belonged to serotype O149:K91, K88ac;--hemolysin was produced by 8 strains which could no be serotyped; 1 strain produced-hemolysin and possessed fimbrial antigens K88; the remaining 3 strains were enterohemolytic and VT producers. Among the 85 non-hemolytic strains, 11 showed some antigenic properties. Only 3 could be serotyped (O64:K 'V142'; O157:K 'V17' and O149:K91); 4 had fimbrial antigens K88 and 1 strain was K99, and 3 possessed capsular antigen (K89). According to these results it is possible to conclude that both hemolytic and non-hemolytic E. coli strains could be pathogenic.