title: Detection of biofilm-grown Aspergillus fumigatus by means of atomic force spectroscopy: ultrastructural effects of alginate lyase.
abstract: Aspergillus fumigatus has become a leading cause of fungal morbidity and mortality, especially in immunocompromised patients. This fungus is able to grow as a multicellular community and produce a hydrophobic extracellular matrix (ECM), mainly composed of galactomannan and α-1,3 glucans, to protect itself from host defenses and antimicrobial drugs. This matrix envelops the fungus hyphae, binding them into a contiguous sheath on the colony surface, forming a biofilm and increasing the fungal resistance to adverse environmental factors. Adherence to host cells and resistance to physical removal play a key role in fungal colonization and invasion of the host and in a wide range of infections. Here we show that, by using atomic force spectroscopy, it is possible to exploit the peculiar hydrophobicity of the biofilm components (i.e., cell walls, ECM) to detect the biofilm spread, its growth, and lysis on rough surfaces. By means of this approach, we demonstrate that alginate lyase, an enzyme known to reduce negatively charged alginate levels in microbial biofilms, reduces the biofilm adhesion forces suggesting a loss of ECM from the biofilm, which could be used to enhance pharmacological treatments.
authors.affiliation: Istituto di Fisica, Università Cattolica del S. Cuore, L. go F. Vito 1, 00168 Roma, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Papi
authors.forename: A
authors.initials: A
authors.lastname: Maiorana
authors.forename: F
authors.initials: F
authors.lastname: Bugli
authors.forename: R
authors.initials: R
authors.lastname: Torelli
authors.forename: B
authors.initials: B
authors.lastname: Posteraro
authors.forename: G
authors.initials: G
authors.lastname: Maulucci
authors.forename: M
authors.initials: M
authors.lastname: De Spirito
authors.forename: M
authors.initials: M
authors.lastname: Sanguinetti
mesh_terms: D001232:Aspergillus fumigatus / Q000737:chemistry / Q000166:cytology / Q000201:enzymology* / Q000254:growth & development*; D018441:Biofilms / Q000254:growth & development; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D018625:Microscopy, Atomic Force; D011133:Polysaccharide-Lyases / Q000737:chemistry* / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase