Title |
Biofilm characterization of Fusarium solani keratitis isolate: increased resistance to antifungals and UV light |
Author |
Itzel Margarita Córdova-Alcántara1, Diana Laura Venegas-Cortés1, María Ángeles Martínez-Rivera1, Néstor Octavio Pérez2*, and Aida Verónica Rodriguez-Tovar1* |
Address |
1Medical Micology Laboratory, Microbiology Department National School of Biological Sciences, National Polytechnique Institute (IPN), C.P. 11340 Ciudad de México, México, 2Research and Development Department, Probiomed S.A. de C.V. Cruce de Carreteras Acatzingo-Zumpahuacan S/N C.P. 52400 Tenancingo, Estado de México, México |
Bibliography |
Journal of Microbiology, 57(6),485–497, 2019,
|
DOI |
10.1007/s12275-019-8637-2
|
Key Words |
Fusarium solani, biofilm, scanning electron microscopy,
antifungal susceptibility, epifluorescence microscopy,
extracellular matrix, ultraviolet light |
Abstract |
Fusarium solani has drawn phytopathogenic, biotechnological,
and medical interest. In humans, it is associated with
localized infections, such as onychomycosis and keratomycosis,
as well as invasive infections in immunocompromised
patients. One pathogenicity factor of filamentous fungi is biofilm
formation. There is still only scarce information about
the in vitro mechanism of the formation and composition of
F. solani biofilm. In this work, we describe the biofilm formed
by a clinical keratomycosis isolate in terms of its development,
composition and susceptibility to different antifungals and
ultraviolet light (UV) at different biofilm formation stages.
We found five biofilm formation stages using scanning electron
microscopy: adherence, germination, hyphal development,
maturation, and cell detachment. Using epifluorescence
microscopy with specific fluorochromes, it was elucidated
that the extracellular matrix consists of carbohydrates, proteins,
and extracellular DNA. Specific inhibitors for these
molecules showed significant biofilm reductions. The antifungal
susceptibility against natamycin, voriconazole, caspofungin,
and amphotericin B was evaluated by metabolic activity
and crystal violet assay, with the F. solani biofilm preformation
to 24 h increased in resistance to natamycin, voriconazole,
and caspofungin, while the biofilm preformation
to 48 h increased in resistance to amphotericin B. The preformed
biofilm at 24 h protected and reduced UV light
mortality. F. solani isolate could produce a highly structured
extra biofilm; its cellular matrix consists of carbohydrate polymers,
proteins, and eDNA. Biofilm confers antifungal resistance
and decreases its susceptibility to UV light. The fungal
biofilm functions as a survival strategy against antifungals
and environmental factors. |