[Properties of E. coli isolated from pigs].

A total of 127 strains of Escherichia coli were isolated from the small intestine, mesenterial lymph nodes, and parenchymal organs from dead pigs or pigs that were killed for diagnostic purpose as well as from rectal swab samples taken from diseased or clinically normal animals. All were studied with regard to haemolytic properties via biochemical and serologic methods along for sensitivity to antibiotics. It was found that the isolated strains manifested characteristic biochemical behaviour (79 of them proved haemolytic, and 48 were nonhaemolytic ). About 30 per cent of all strains contained the K88 antigen. This antigen was encountered more frequently in the strains that were isolated on small pig farms as well in those that were isolated from dead animals. In the period of studies on the farms prevailed strains that belonged to serologic groups O45 and O138 . In recent years the resistance of the E. coli strains as regards antibiotics has grown considerably. The percent of resistant strains has been higher on the industrial swine-breeding complexes as compared to the smaller farms.