ction, but other Pseudomonas aeruginosa genes involved in the infection process. A current study is investigating this by isolating genes that are regulated by AlgR and characterizing those genes to determine whether they are used by Pseudomonas aeruginosa to evade the bodys immune response and cause disease. The effects of the isolated genes will be measured on the ability of the bacteria to bind to the cells lining the airway and to avoid ingestion and destruction of defending white blood cells. Results from these studies will give insight into the disease causing mechanisms in Pseudomonas aeruginosa and may lead to alternate methods of infection prevention in the CF patient. Complications associated with Pseudomonas aeruginosa lung infections in CF patients are the result of a multitude of pathogenic mechanisms in the respiratory tract created by the underlying chloride channel defect. Gene mapping studies of Pseudomonas aeruginosa will help researchers and clinicians better understand local gene expression and the evolution of Pseudomonas aeruginosa as it has adapted to the CF lung. Researchers are using new genetic tools to study bacterial virulence mechanisms during infection with Pseudomonas aeruginosa. Two techniques employed to determine the extent of genomic variation among different Pseudomonas aeruginosa clinical isolates are macroevolutional and microevolutional analysis. In macroevolutional analysis DNA arrays were used to identify genes in clinical strains of Pseudomonas aeruginosa that were absent in strain PA01 (the Pseudomonas Genome Project strain sequence). Using labeled genomic DNA probes, strains were assessed for reaction with PA01 probes, which represented sequences unique for the clinical strains. The isolates were sequenced and assembled into contigs, or contiguous coding regions, to determine the genetic structure of the strains. Using 2 clinical strains, the first isolated from a catheterized...
