Aspergillus fumigatus (Af) biofilm and the effect of Pseudomonas aeruginosa (Pa) phenotypes

Ref ID: 19522

Author:

JC Penner1*, H Nazik1,2, KV Clemons1,3, DA Stevens1,3, RB Moss3, N Banaei3, JAG Ferreira1,3,4

Author address:

1Department of Infectious Diseases, California Institute for Medical Research, San Jose, United States of
America
2Department of Medical Microbiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
3School of Medicine, Stanfor

Full conference title:

6th Advances Against Aspergillosis 2014

Abstract:

Purpose:
Pa and Af frequently infect the airways of patients with cystic fibrosis (CF), and form biofilms there.
Our purpose was to examine the impact of Pa isolates from CF or non-CF patients, various colonial
phenotypes, and spent culture filtrates of these Pa isolates on the development of established Af
biofilm.
Methods:
26 clinical Pa isolates (16 non-CF isolates (nonCF); 5 CF mucoid variant (CFMuc), 5 CF non-mucoid
(CFNMuc)), and one Af strain (10AF) were studied. To form Af biofilm (AfBF), an inoculum of
3 x 105 conidia in fresh RPMI+10% fetal bovine serum was grown on flat, polystyrene disks in
12-well tissue culture plates for 16 hours before challenge with 3 x 107 live Pa cells, spent culture
filtrates (SCF) from Pa grown 16 hrs in planktonic (PK) or biofilm (BF) conditions, or fresh medium
(controls). After 24 hrs further incubation, AfBF metabolic activity was evaluated using an XTT
assay. Statistical differences were evaluated using one-way analysis of variance (ANOVA) with a
Tukey post-hoc test; statistical significance was considered p 8804; 0.05.
Results:
Pa CFNMuc isolates inhibited AfBF reduction of XTT (p<0.01), whereas nonCF and CFMuc Pa isolates had no significant effect. CFNMuc Pa isolates inhibited AfBF to a greater extent than either nonCF or CFMuc isolates (p< 0.001 both comparisons). SCF grown under either PK or BF conditions from CFNMuc isolates were inhibitory to the AfBF (p<0.001 for both conditions), whereas SCF grown under either condition from nonCF or CFMuc isolates had no significant effect. SCF grown under PK or BF conditions from CFNMuc isolates was more inhibitory than that from nonCF or CFMuc isolates grown under the same respective conditions (p<0.001 for all 4 comparisons). Additionally, SCF grown as BF from CFNMuc isolates appeared more inhibitory than SCF grown under PK conditions from CFNMuc isolates; there did not appear a difference in inhibition between SCF grown under PK or BF conditions for nonCF or CFMuc isolates. Serial dilutions of fresh complete media with distilled water indicated the observed inhibition with SCF was not merely due to the prior exhaustion of SCF, but to soluble, Af-inhibiting component(s) produced by CFNMuc Pa, particularly under BF conditions. Conclusion: Live cells or spent media from planktonic or biofilm cultures of CFNMuc Pa significantly inhibited the metabolic activity of preformed Af biofilm. This suggests that CFNMuc isolates inhibit the further growth of already established Af biofilm, and do so to a greater extent than nonCF or CFMuc isolates. An hypothesis is that the transition from non-mucoid to mucoid Pa during colonization of CF airways plays a role in enabling development of Af biofilm, thus augmenting Af establishment.

Abstract Number: 49

Conference Year: 2014

Link to conference website: http://www.AAA2014.org

New link: NULL

Conference abstracts, posters & presentations

Showing 10 posts of 17325 posts found.

  • Title

    Author

    Year

    Number

    Poster