AGGREGATIVE ADHERENCE OF KLEBSIELLA-PNEUMONIAE TO HUMAN INTESTINE-407CELLS

Aggregative adhesion of Klebsiella pneumoniae LM3 to Intestine-407 (In t-407) cells was studied, Adhesive capacities were affected by the bac terial growth phase (with a maximum of adherence obtained during the e xponential phase), temperature, multiplicity of infection, and length of incubation with Int-407 cells, Adhesion occurred through a cytochal asin D-sensitive process and was greatly reduced after treatment of In t-407 with cycloheximide, indicating that aggregative adhesion require s active participation of Int-407 cells. Transmission electron microsc opy revealed that adherent bacteria were surrounded by a capsule-like material, apparently involved in both bacterium-Int-407 cell and bacte rium-bacterium adherence, Examination with a scanning electron microsc ope showed interactions of intestinal cell microvilli with bacteria an d formation in 3 h of a fibrous network within and around the bacteria l clusters. We speculate that aggregative adhesion of K. pneumoniae me diated by a capsule-like extracellular material might explain the pers istence of these strains inside the host gastrointestinal tract.