title: Aspergillus fumigatus enhances elastase production in Pseudomonas aeruginosa co-cultures.
abstract: In the cystic fibrosis (CF) lung the presence of bacteria and fungi in the airways promotes an inflammatory response causing progressive lung damage, ultimately leading to high rates of morbidity and mortality. We hypothesized that polymicrobial interactions play an important role in promoting airway pathogenesis. We therefore examined the interplay between the most commonly isolated bacterial CF pathogen, Pseudomonas aeruginosa, and the most prevalent filamentous fungi, Aspergillus fumigatus, to test this. Co-culture experiments showed that in the presence of A. fumigatus the production of P. aeruginosa elastase was enhanced. This was confirmed by the presence of zones of clearance on Elastin-Congo Red (ECR) agar, which was identified as elastase by mass spectrometry. When P. aeruginosa were grown in a co-culture model with mature A. fumigatus biofilms, 60% of isolates produced significantly more elastase in the presence of the filamentous fungi than in its absence (P < .05). The expression of lasB also increased when P. aeruginosa isolates PA01 and PA14 were grown in co-culture with A. fumigatus. Supernatants from co-culture experiments were also significantly toxic to a human lung epithelial cell line (19-38% cell cytotoxicity) in comparison to supernatants from P. aeruginosa only cultures (P < .0001). Here we report that P. aeruginosa cytotoxic elastase is enhanced in the presence of the filamentous fungi A. fumigatus, suggesting that this may have a role to play in the damaging pathology associated with the lung tissue in this disease. This indicates that patients who have a co-colonisation with these two organisms may have a poorer prognosis.
authors.affiliation: Institute of Healthcare Associated Infection, School of Health, Nursing and Midwifery, University of the West of Scotland, United Kingdom.
authors.forename: Karen
authors.initials: K
authors.lastname: Smith
authors.affiliation: Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom.
authors.forename: Ranjith
authors.initials: R
authors.lastname: Rajendran
authors.affiliation: Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom.
authors.forename: Stephen
authors.initials: S
authors.lastname: Kerr
authors.affiliation: Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom.
authors.forename: David F
authors.initials: DF
authors.lastname: Lappin
authors.affiliation: Institute of Healthcare Associated Infection, School of Health, Nursing and Midwifery, University of the West of Scotland, United Kingdom.
authors.forename: William G
authors.initials: WG
authors.lastname: Mackay
authors.affiliation: Institute of Healthcare Associated Infection, School of Health, Nursing and Midwifery, University of the West of Scotland, United Kingdom.
authors.forename: Craig
authors.initials: C
authors.lastname: Williams
authors.affiliation: Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom gordon.ramage@glasgow.ac.uk.
authors.forename: Gordon
authors.initials: G
authors.lastname: Ramage
mesh_terms: D001228:Aspergillosis / Q000382:microbiology; D001232:Aspergillus fumigatus / Q000254:growth & development* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000378:metabolism*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002648:Child; D002675:Child, Preschool; D003470:Culture Media / Q000737:chemistry; D003550:Cystic Fibrosis / Q000150:complications; D004847:Epithelial Cells / Q000187:drug effects / Q000502:physiology; D020869:Gene Expression Profiling; D006801:Humans; D013058:Mass Spectrometry; D008666:Metalloendopeptidases / Q000096:biosynthesis* / Q000378:metabolism*; D056265:Microbial Interactions; D008828:Microbiological Techniques; D011552:Pseudomonas Infections / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000254:growth & development* / Q000302:isolation & purification
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D008666:Metalloendopeptidases; C043859:pseudolysin, Pseudomonas aeruginosa
keywords: Aspergillus; Pseudomonas; biofilms; cystic fibrosis; elastase