title: Gene expression characteristics of a cystic fibrosis epidemic strain of Pseudomonas aeruginosa during biofilm and planktonic growth.
abstract: Epidemic Pseudomonas aeruginosa have been identified in cystic fibrosis (CF) patients worldwide. The Australian Epidemic Strain-2 (AES-2) infects up to 40% of patients in three eastern Australian CF clinics. To investigate whether AES-2 isolates from chronically infected CF adults differentially express well-conserved genes potentially associated with transmissibility, we compared the transcriptomes of planktonic and biofilm-grown AES-2, infrequent P. aeruginosa clones and the reference P. aeruginosa PAO1 using the Affymetrix PAO1 array. The most interesting findings emerged from comparisons of planktonic and biofilm AES-2. AES-2 biofilms upregulated Type III secretion system genes, but downregulated quorum-sensing (QS)-regulatory genes, except lasR, QS-regulated, oxidative-stress and iron-storage genes. QS-regulated and iron-storage genes were downregulated to a greater extent in AES-2 biofilms compared with infrequent clone and PAO1 biofilms, suggesting enhanced anaerobic respiration in AES-2. Chitinase and chitin-binding protein maintained high expression in AES-2 biofilms compared with infrequent clone and PAO1 biofilms. Planktonic AES-2 upregulated QS regulators and QS-regulated genes, iron acquisition and aerobic respiration genes, and had high expression of Group III Type IV pilA compared with low expression of Group I Type IV pilA in infrequent clones. Together, these properties may enhance long-term survival of AES-2 in CF lung and contribute to its transmissibility.
authors.affiliation: Department of Infectious Diseases and Immunology, University of Sydney, Sydney, NSW, Australia. jmanos@infdis.usyd.edu.au
authors.forename: Jim
authors.initials: J
authors.lastname: Manos
authors.forename: Jonathan
authors.initials: J
authors.lastname: Arthur
authors.forename: Barbara
authors.initials: B
authors.lastname: Rose
authors.forename: Scott
authors.initials: S
authors.lastname: Bell
authors.forename: Pholawat
authors.initials: P
authors.lastname: Tingpej
authors.forename: Honghua
authors.initials: H
authors.lastname: Hu
authors.forename: Jeremy
authors.initials: J
authors.lastname: Webb
authors.forename: Staffan
authors.initials: S
authors.lastname: Kjelleberg
authors.forename: Mark Douglas
authors.initials: MD
authors.lastname: Gorrell
authors.forename: Peter
authors.initials: P
authors.lastname: Bye
authors.forename: Colin
authors.initials: C
authors.lastname: Harbour
mesh_terms: D000328:Adult; D000693:Anaerobiosis; D018441:Biofilms / Q000254:growth & development*; D003550:Cystic Fibrosis / Q000382:microbiology; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D053858:Metabolic Networks and Pathways / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D011552:Pseudomonas Infections / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000254:growth & development* / Q000302:isolation & purification / Q000502:physiology; D055815:Young Adult