SOME BIOLOGICAL CHARACTERISTICS OF ESCHERICHIA-COLI STRAINS ISOLATED FROM ACUTE DIARRHEAL DISEASES OF INFANTS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 244  (4) , 439-451
Abstract
Methods for biological characterization of E. coli strains were evaluated as screening tests in clinical microbiological laboratories. In 2/3 of the 45 E. coli strains isolated from acute intestinal infection of human infants, different virulence factors were found. The enterotoxigenic character prevailed (66.6%) which correlated with the increased permeability (62.2%). Adhesive properties were present in 20% of E. coli independent of their enterotoxigenicity; only 11.1% of the strains were invasive. The rabbit skin model seems to be accurate and quick for enterotoxigenicity screening, as is the guinea pig eye for determining invasiveness. The mouse intestinal loop is sensitive but time-consuming. The infant mouse model is simple and quick but did not give optimal results. The Vero [African green monkey kidney] cell culture system is simple and easy to perform, but for some strains the preparation should be concentrated. The investigation of adhesiveness by hemagglutination is feasible even for the small clinical laboratory. After isolation of E. coli from pathological materials, determination of the antigenic structure of the strains is necessary and later additional biological characterization should be performed.