title: Antifungal activity of Myriocin on clinically relevant Aspergillus fumigatus strains producing biofilm.
abstract: BACKGROUND
  The human pathogenic mold Aspergillus fumigatus is able to form a complex biofilm embedded in extracellular matrix. Biofilms confer antimicrobial resistance and it is well known that aspergillosis is often refractory to the conventional antifungal therapy. The treatment of biofilm-related infections poses a significant clinical challenge on a daily basis, promoting the search for new therapeutic agents. Our aim was to exploit the modulation of sphingolipid mediators as new therapeutic target to overcome antifungal resistance in biofilm-related infections.
  
  
  RESULTS
  Antifungal susceptibility testing was performed on 20 clinical isolates of Aspergillus fumigatus and one reference strain (A. fumigatus Af293) according the EUCAST protocol. Sessile MICs were assessed on 24-h preformed-biofilm by means of XTT-reduction assay. Myriocin (0.25-64 mg/L), a commercial sphingolipid synthesis inhibitor, was used. The MEC50 value (mg/L) of Myriocin was 8 (range 4-16) for both planktonic and sessile cells. Drug-induced morphological alterations were analyzed by optical and electron microscopy (TEM) on 24h preformed A. fumigatus Af293 biofilms. An evident hyphal damage, resulting in short, stubby, and highly branched hyphae was observed by optical microscopy. At 24h, TEM studies showed important morphological alterations, such as invaginations of the cell membrane, modification in the vacuolar system and presence of multilamellar bodies, in some cases within vacuoles.
  
  
  CONCLUSIONS
  The direct antifungal activity, observed on both planktonic and sessile fungi, suggests that inhibition of sphingolipid synthesis could represent a new target to fight biofilm-related A. fumigatus resistance.
authors.affiliation: Department of Health Sciences, Università degli Studi di Milano, Polo Universitario San Paolo, Blocco C, ottavo piano, via di Rudinì 8, 20142, Milan, Italy. federica.perdoni@unimi.it.
authors.forename: Federica
authors.initials: F
authors.lastname: Perdoni
authors.affiliation: Department of Health Sciences, Università degli Studi di Milano, Polo Universitario San Paolo, Blocco C, ottavo piano, via di Rudinì 8, 20142, Milan, Italy. paola.signorelli@unimi.it.
authors.forename: Paola
authors.initials: P
authors.lastname: Signorelli
authors.affiliation: Department of Health Sciences, Università degli Studi di Milano, Polo Universitario San Paolo, Blocco C, ottavo piano, via di Rudinì 8, 20142, Milan, Italy. daniela.cirasola@unimi.it.
authors.forename: Daniela
authors.initials: D
authors.lastname: Cirasola
authors.affiliation: Department of Health Sciences, Università degli Studi di Milano, Polo Universitario San Paolo, Blocco C, ottavo piano, via di Rudinì 8, 20142, Milan, Italy. anna.caretti@unimi.it.
authors.forename: Anna
authors.initials: A
authors.lastname: Caretti
authors.affiliation: Department of Biology and Biotechnology, Università degli Studi di Pavia, Pavia, Italy. valentina.galimberti@unipv.it.
authors.forename: Valentina
authors.initials: V
authors.lastname: Galimberti
authors.affiliation: Department of Biology and Biotechnology, Università degli Studi di Pavia, Pavia, Italy. marco.biggiogera@unipv.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Biggiogera
authors.affiliation: Nanovector Srl, Torino, Italy. paolo.gasco@nanovector.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Gasco
authors.affiliation: Nanovector Srl, Torino, Italy. claudia.musicanti@nanovector.it.
authors.forename: Claudia
authors.initials: C
authors.lastname: Musicanti
authors.affiliation: Department of Health Sciences, Università degli Studi di Milano, Polo Universitario San Paolo, Blocco C, ottavo piano, via di Rudinì 8, 20142, Milan, Italy. giulia.morace@unimi.it.
authors.forename: Giulia
authors.initials: G
authors.lastname: Morace
authors.affiliation: Department of Health Sciences, Università degli Studi di Milano, Polo Universitario San Paolo, Blocco C, ottavo piano, via di Rudinì 8, 20142, Milan, Italy. elisa.borghi@unimi.it.
authors.forename: Elisa
authors.initials: E
authors.lastname: Borghi
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D001228:Aspergillosis / Q000382:microbiology; D001232:Aspergillus fumigatus / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology; D018441:Biofilms / Q000187:drug effects*; D025141:Drug Resistance, Fungal / Q000187:drug effects; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology*; D006801:Humans; D025301:Hyphae / Q000187:drug effects; D008826:Microbial Sensitivity Tests / Q000379:methods; D050296:Microbial Viability / Q000187:drug effects
chemical_list: D000935:Antifungal Agents; D005229:Fatty Acids, Monounsaturated; C001996:thermozymocidin