[Biological properties of enterotoxigenic Escherichia isolated from patients with acute intestinal diseases of unknown etiology]. 
As the result of the comparative examination of adult patients with acute enteric diseases and normal adults, 173 E. coli enterotoxigenic strains were isolated (161 strains from the patients and 12 strains from normal persons).  83% of the isolated enterotoxigenic E. coli (ETEC) produced two enterotoxins: thermolabile (LT) and thermostable (ST).  Enterotoxigenicity was most pronounced in the strains of ETEC belonging to the prevaling variant ST + LT +.  The enterotoxigenic properties of ETEC were highly stable: the production of ST and LT in the strains remained unchanged after their storage for up to 4 years.  The isolated ETEC comprised 48 serogroups and 61 strains.  The strains belonging to the same seroval had a similar degree of toxigenicity.  The strains belonging to different serovars considerably differed in the activity of their enterotoxins.  The production of two kinds of enterotoxins in the isolated E. coli strains was inter-related: the strains with a high activity of ST were, as a rule, good producers of LT.