Pseudomonas-epithelial cell interactions dissected with DNA microarrays.

R espiratory infections by the opportunistic pathogen Pseudomonas aeruginosa in immunocompromised patients or in patients with cystic fibrosis (CF) are the result of unique conditions that allow this Gram-negative bacterium to colonize the lung. This interaction between the pathogen and host leads to responses in both cells that ultimately lead to severe lung degeneration in individuals with CF. Recently, several new resources and technologies have become available to investigators, which should greatly accelerate our understanding of the mechanism of P aeruginosa pathogenesis, as well as of host defenses. Foremost among these are DNA microarrays, which allow transcriptional profiling of the partial or entire genetic repertoires of the pathogen and its host. A comprehensive compendium of expression profiles will serve in understanding the complex interplay between pathogen and host during respiratory infections.