We substantially extend this observation to include numerous other organisms commonly cultured from CF patients (mucoid Pa, Staphylococcus aureus, MRSA, Aspergillus fumigatus, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, atypical mycobacterium and Klebsiella pneumoniae) indicating that CFTR dysfunction appears to cause a global alteration in infection resistance in humans. This evidence concerns the gene CFTR and infection.