THE EFFECT OF ANTI-EXOTOXIN-A ON THE ADHERENCE OF PSEUDOMONAS-AERUGINOSA TO HAMSTER TRACHEAL EPITHELIAL-CELLS IN-VITRO

One of the most important initial events of colonization and infection of epithelial tissues is the adherence of bacteria to mucosal surface s. Bacterial adhesion to the epithelial cell may be mediated by a vari ety of adhesins, including exoproducts. One of these exoproducts, exot oxin A (EA) is a three-domain bacterial toxin that kills mammalian cel ls by gaining entry to the cytosol and inactivating protein synthesis. In the present study, HTE cultures, 2-4 weeks in vitro (containing bo th ciliated and non-ciliated cells), were treated for 1 hr with two di fferent non-mucoid strains of Pseudomonas aeruginosa (1 x 10(8) organi sms/ml) in the presence of anti-EA. 50 randomly selected fields were e valuated via SEM at x2500 magnification and the number of bacterial cl usters/field quantitated. The results of this study indicate, first, t hat both piliated (ATCC15692) and non-piliated (PAKp) P. aeruginosa wi ll bind to the HTE cells and, second, that treatment of HTE cells with either strain of P. aeruginosa in the presence of anti-EA will reduce bacterial binding by 25% to 50%. Thus, EA may participate in the adhe sion of P. aeruginosa to respiratory tract epithelia.