ESCHERICHIA-COLI STRAINS PRODUCING HEAT-S TABLE ENTEROTOXIN (ST) AND VEROTOXIN (VT) ISOLATED FROM DIARRHEIC CALVES AND LAMBS

Due to its importance in bovine and ovine neonatal mortality, the pres ence of E. coli strains that produce heat-stable enterotoxin (ST) and verotoxin (VT) was studied in faeces on neonate calves and lambs. Four ty seven and thirty one faeces samples were collected from calves and lambs with diarrhoea, respectively. Samples were cultivated in both eo sin-metilen blue and ovine blood agar in order to study the characteri stics of the colonies and to biochemically identify the isolated strai ns, The production of ST toxin was tested by the infant mouse techniqu e. Detection of VT was performed by the micromethod of Vero cell cultu re. Three (6.4%) positive and 8 (17%) suspicious strains to ST as well as 1 (2.1%) positive strain to VT were isolated from calves. On the o ther hand, in neonate lambs 2 (6.5%) strains were doubtful to ST and 2 (6.5%) were VT producer strains. Their possible role in the pathogene sis of the diarrhea is discussed. The possibility that both animal spe cies could be infection sources to man is also considered.