title: Biofilm Filtrates of Pseudomonas aeruginosa Strains Isolated from Cystic Fibrosis Patients Inhibit Preformed Aspergillus fumigatus Biofilms via Apoptosis.
abstract: Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) colonize cystic fibrosis (CF) patient airways. Pa culture filtrates inhibit Af biofilms, and Pa non-CF, mucoid (Muc-CF) and nonmucoid CF (NMuc-CF) isolates form an ascending inhibitory hierarchy. We hypothesized this activity is mediated through apoptosis induction. One Af and three Pa (non-CF, Muc-CF, NMuc-CF) reference isolates were studied. Af biofilm was formed in 96 well plates for 16 h ± Pa biofilm filtrates. After 24 h, apoptosis was characterized by viability dye DiBAc, reactive oxygen species (ROS) generation, mitochondrial membrane depolarization, DNA fragmentation and metacaspase activity. Muc-CF and NMuc-CF filtrates inhibited and damaged Af biofilm (p<0.0001). Intracellular ROS levels were elevated (p<0.001) in NMuc-CF-treated Af biofilms (3.7- fold) compared to treatment with filtrates from Muc-CF- (2.5- fold) or non-CF Pa (1.7- fold). Depolarization of mitochondrial potential was greater upon exposure to NMuc-CF (2.4-fold) compared to Muc-CF (1.8-fold) or non-CF (1.25-fold) (p<0.0001) filtrates. Exposure to filtrates resulted in more DNA fragmentation in Af biofilm, compared to control, mediated by metacaspase activation. In conclusion, filtrates from CF-Pa isolates were more inhibitory against Af biofilms than from non-CF. The apoptotic effect involves mitochondrial membrane damage associated with metacaspase activation.
authors.affiliation: Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas M D Anderson Cancer Center, Houston, TX, 77030, United States of America.
authors.forename: Fazal
authors.initials: F
authors.lastname: Shirazi
authors.affiliation: Div. of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California, 94305, United States of America.|California Institute for Medical Research, San Jose, California, 95128, United States of America.
authors.forename: Jose A G
authors.initials: JA
authors.lastname: Ferreira
authors.affiliation: Div. of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California, 94305, United States of America.|California Institute for Medical Research, San Jose, California, 95128, United States of America.
authors.forename: David A
authors.initials: DA
authors.lastname: Stevens
authors.affiliation: Div. of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California, 94305, United States of America.|California Institute for Medical Research, San Jose, California, 95128, United States of America.
authors.forename: Karl V
authors.initials: KV
authors.lastname: Clemons
authors.affiliation: Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas M D Anderson Cancer Center, Houston, TX, 77030, United States of America.
authors.forename: Dimitrios P
authors.initials: DP
authors.lastname: Kontoyiannis
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D001232:Aspergillus fumigatus / Q000254:growth & development* / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D003550:Cystic Fibrosis / Q000382:microbiology*; D053938:DNA Fragmentation; D006801:Humans; D051336:Mitochondrial Membranes / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species