Modulation of host cell membrane fluidity: a novel mechanism for preventing bacterial adhesion

Adhesion of bacterial enteropathogens to host mucosal surfaces is a critica l primary step in the pathogenesis of diarrheal disease. We investigated th e effects of altering the physical properties of eukaryotic cells on bacter ial adhesion with the use of a series of three structurally dissimilar memb rane fluidizers and several Escherichia coli as test strains. Lipid fluidit y of the cell plasma membrane was measured by steady-state fluorescence ani sotropy employing the probe 1-(4-trimethylammoniumphenyl)-6-phenyl-1 hexatr iene. There was a dose-dependent and reversible inhibition of bacterial adh esion with increasing membrane fluidity. Time course experiments indicated that increasing membrane fluidity during the early stages of bacterial adhe sion was essential for inhibition of attachment. None of the fluidizers aff ected the viability of either eukaryotic or prokaryotic cells. These findin gs demonstrate, for the first time, that changes in plasma membrane physica l properties of epithelial cells can prevent microbial adhesion. This also suggests that altering the membrane properties of host cells could form a b asis for novel strategies to prevent bacterial adhesion during infection in vivo.