Related Experiment Video
Updated: Aug 17, 2025
Clarifying and Imaging Candida albicans Biofilms
Published on: March 6, 2020
Lipid-Like Biofilm from a Clinical Brain Isolate of Aspergillus terreus: Quantification, Structural Characterization
Gerardo Rayón-López1, Natalee Carapia-Minero1, María Gabriela Medina-Canales2
1Medical Mycology Laboratory, Microbiology Department, Escuela Nacional de Ciencias Biológicas (ENCB), Instituto Politécnico Nacional (IPN), Mexico City, Mexico.
Abstract:
Invasive infections caused by filamentous fungi have increased considerably due to the alteration of the host's immune response. Aspergillus terreus is considered an emerging pathogen and has shown resistance to amphotericin B treatment, resulting in high mortality. The development of fungal biofilm is a virulence factor, and it has been described in some cases of invasive aspergillosis. In addition, although the general composition of fungal biofilms is known, findings related to biofilms of a lipid nature are rarely reported. In this study, we present the identification of a clinical strain of A. terreus by microbiological and molecular tools, also its in vitro biofilm development capacity: (i) Biofilm formation was quantified by Crystal Violet and reduction of tetrazolium salts assays, and simultaneously the stages of biofilm development were described by Scanning Electron Microscopy in High Resolution (SEM-HR). (ii) Characterization of the organizational structure of the biofilm was performed by SEM-HR. The hyphal networks developed on the surface, the abundant air channels created between the ECM (extracellular matrix) and the hyphae fused in anastomosis were described. Also, the presence of microhyphae is reported. (iii) The chemical composition of the ECM was analyzed by SEM-HR and CLSM (Confocal Laser Scanning Microscopy). Proteins, carbohydrates, nucleic acids and a relevant presence of lipid components were identified. Some structures of apparent waxy appearance were highlighted by SEM-HR and backscatter-electron diffraction, for which CLSM was previously performed. To our knowledge, this work is the first description of a lipid-type biofilm in filamentous fungi, specifically of the species A. terreus from a clinical isolate.
Insights
This study identifies a lipid-type biofilm in Aspergillus terreus, an emerging fungal pathogen. This discovery offers new insights into invasive fungal infections and potential therapeutic targets.
Area of Science:
- Mycology
- Medical Microbiology
- Fungal Pathogenesis
Background:
- Invasive filamentous fungal infections are increasing due to altered host immunity.
- Aspergillus terreus is an emerging pathogen with high mortality, often resistant to antifungal treatments.
- Fungal biofilms are virulence factors in invasive aspergillosis, but lipid-rich biofilms are rarely reported.
Purpose of the Study:
- To identify a clinical strain of Aspergillus terreus.
- To characterize its in vitro biofilm development capacity and structure.
- To analyze the chemical composition of the extracellular matrix (ECM) of the biofilm.
Main Methods:
- Microbiological and molecular identification of Aspergillus terreus.
- Quantification of biofilm formation using Crystal Violet and tetrazolium salt assays.
- High-resolution Scanning Electron Microscopy (SEM-HR) for biofilm structure and development stages.
- Confocal Laser Scanning Microscopy (CLSM) and backscatter-electron diffraction for ECM chemical analysis.
Main Results:
- The study successfully identified a clinical strain of A. terreus with significant in vitro biofilm development capacity.
- SEM-HR revealed detailed biofilm architecture, including hyphal networks, air channels, and fused hyphae.
- Chemical analysis of the ECM identified proteins, carbohydrates, nucleic acids, and a notable presence of lipid components, suggesting a lipid-type biofilm.
Conclusions:
- This research presents the first description of a lipid-type biofilm in filamentous fungi, specifically from a clinical isolate of Aspergillus terreus.
- The findings contribute to understanding the virulence factors of A. terreus and the composition of fungal biofilms.
- This discovery may open new avenues for diagnosing and treating invasive aspergillosis, particularly infections involving lipid-rich biofilms.
