[Factors and markers of virulence of Escherichia coli strains isolated from diarrhea in calves aged 4-45 days in Algeria].

The study involved 492 strains of Escherichia coli isolated from the feces of 44 diarrhoeal calves and 4 healthy calves in 7 wilayates in Algeria (Tipaza, Ain Defla, Bejaïa, Borj Bou Arreridj, Bouira, Medea and Algiers). The authors looked for the surface proteins K99, CS31A, Vir, F17 (FY), 20K and certain factors or markers of virulence such as the production of colicins, particularly colicin V, the aerobactin siderophore, alpha hemolysin and enterohemolysin. They also studied the frequency of certain 0 serogroups and evaluated the resistance of the E. coli strains to 10 antibiotics. The results showed that the majority of diarrhoeal calves were colonized by Escherichia coli expressing one or more factors of virulence and that the stocks which produce the antigen CS31A are usually resistant to 4 or 6 antibiotics.