[Biological properties of opportunistic enterobacteria isolated from the blood of patients].

The comparative study of the signs of pathogenicity in enterobacteria (119 strains) isolated from the blood of 145 patients with the clinical symptoms of sepsis and from the feces of healthy persons (560 strains from 220 persons) has demonstrated that the same species of opportunistic microorganisms may essentially differ in the formation of DNase, RNase, as well as in their capacity for the positive reaction with Congo red. The possibility of using the above-mentioned signs of pathogenicity for diagnostic purposes as additional signs for the differentiation of virulent cultures of opportunistic enterobacteria from avirulent ones is suggested.