Abstract
A model of the adherence of P. aeruginosa to injured lower respiratory tract cells is described. Mouse tracheas were injured by exposure to 0.1 N HCl for 15 min, cut into pieces of 2-4 rings and placed in petri dishes for adherence studies. Adherence was quantitated by direct count of the number of bacteria attached to a fixed surface area as viewed by scanning EM. Optimal conditions for study were 1 h of incubation with an inoculum of 107-108 colony-forming units/ml. Mucoid and nonmucoid P. aeruginosa adhered to the injured cells in this system; no major differences in adherence between these strains was apparent. Adherence to injured tracheal cells was a phenomenon limited to P. aeruginosa, and did not occur with Escherichia coli and Klebsiella pneumoniae. Besides adherence to injured cells, this model allowed the demonstration of adherence of mucoid P. aeruginosa and K. pneumoniae to mucin strands of uninjured control tracheas. This model is an alternative to the buccal cell model and has the advantage of allowing the study of the adherence of mucoid and nonmucoid strains of P. aeruginosa.