[Electrophoretic typing of Escherichia coli esterases in septicemia].

Esterases produced by 175 strains of Escherichia coli isolated from 34 patients with septicaemia were subjected to electrophoresis in acrylamide-agarose gel. Forty-four electrophoretic types were identified, and the septicaemias were divided into two groups according to whether or not all the strains isolated in a given patient were of the same electrophoretic type. In the first group (21 patients) the presence of one single electrophoretic type demonstrated that the strains isolated from haemocultures and those isolated from focal specimens were identical and could be held responsible for infection in different foci. In the second group (13 patients) the presence of different electrophoretic types in the same patient either discard an relationship between strain from haemoculture and strain from focal specimen, or demonstrated that different strains could coexist in a focus of infection, or revealed successive and overlapping infections. These results not only provide precise information on the nature of bacteria responsible for infections, but also have interesting pathophysiological and epidemiological implications.