title: Protease IV production in Pseudomonas aeruginosa from the lungs of adults with cystic fibrosis.
abstract: Protease IV is important in the pathogenesis of Pseudomonas aeruginosa-induced microbial keratitis, but little is known of its role in cystic fibrosis (CF) lung infection. In this study protease IV production was examined in 43 P. aeruginosa isolates (24 non-clonal and 19 clonal) from the lungs of chronically infected adult patients attending the Royal Prince Alfred Hospital CF Clinic, Sydney, Australia. Overall, 32/43 (74 %) isolates were positive for protease IV protein by Western blotting and 22/43 (51 %) had evidence of active protease IV on gelatin zymography. Clonal strains were 1.6 times more likely than non-clonal strains to produce protease IV [18/19 (95 %) versus 14/24 (58 %), RR=1.6, CI 1.1-2.3, P=0.007] and 3 times more likely to secrete the protein [16/19 (84 %) versus 6/24 (25 %), RR=3.4, CI 1.6-6.9, P<0.001]. Nine of the ten strains negative by both Western blotting and zymography were non-clonal, and all but one of these was positive for the protease IV gene. There was a marked strain-to-strain variation in the amount of protease IV produced. Secretion of protease IV by clonal strains may enhance their infectivity and ability to adapt to the changing CF lung environment. Overall the findings suggest that protease IV plays an important role in the pathogenesis of P. aeruginosa infection in the CF lung.
authors.forename: Lucas
authors.initials: L
authors.lastname: Smith
authors.forename: Barbara
authors.initials: B
authors.lastname: Rose
authors.forename: Pholawat
authors.initials: P
authors.lastname: Tingpej
authors.affiliation: Institute for Eye Research, Sydney, Australia.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhu
authors.affiliation: School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia.
authors.forename: Tim
authors.initials: T
authors.lastname: Conibear
authors.forename: Jim
authors.initials: J
authors.lastname: Manos
authors.affiliation: Department of Respiratory Medicine, Royal Prince Alfred Hospital, Sydney, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Bye
authors.affiliation: Department of Respiratory Medicine, Royal Prince Alfred Hospital, Sydney, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Elkins
authors.affiliation: School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia.|Institute for Eye Research, Sydney, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Willcox
authors.affiliation: Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Brisbane, Australia.
authors.forename: Scott
authors.initials: S
authors.lastname: Bell
authors.affiliation: Department of Respiratory Medicine, Royal Children's Hospital, Brisbane, Australia.
authors.forename: Claire
authors.initials: C
authors.lastname: Wainwright
authors.forename: Colin
authors.initials: C
authors.lastname: Harbour
mesh_terms: D000293:Adolescent; D000328:Adult; D015153:Blotting, Western; D002908:Chronic Disease; D003550:Cystic Fibrosis / Q000150:complications / Q000382:microbiology*; D005260:Female; D005798:Genes, Bacterial; D006801:Humans; D017403:In Situ Hybridization; D008168:Lung / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D010447:Peptide Hydrolases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D011552:Pseudomonas Infections / Q000150:complications / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000472:pathogenicity; D014774:Virulence
chemical_list: D010447:Peptide Hydrolases; C030732:protease IV