[Biochemical and serological studies of the E. coli strains isolated from cows with subclinical mastitis]

Studies were serologically and biochemically a total of 17 strains of Escherichia coli isolated from mastitis-affected cows in the districts of Sofia, Varna, and Plovidiv. Demonstrated were the serogroups 0125, 0111, 086, 025, 026, 055, and 0128, which were pathogenic for humans too. Via the milk they were shown to reach both newborn animals and children and to cause severely expressed colienteritis. All investigated strains attacked glucose and manite, reduced nitrates into nitrites, and gave a positive reaction with methyl red but did not ferment starch, insulin, sucrose, and maltose; neither did they produce hydrogen sulfide and liquefaction of gelatin. They gave a negative Voges-Proscauer reaction. Single strains were negative with regard to lactose and indole, and the strains' activity with regard to sorbite, inosite and adonite varied.