Antifungal activity of Bacillus amyloliquefaciens supernatants against Candida albicans biofilm
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Data di Pubblicazione:
2018
Citazione:
Antifungal activity of Bacillus amyloliquefaciens supernatants against Candida albicans biofilm / G. Bassanini, F. Borgo, E. Ottaviano, G. Morace, E. Borghi. ((Intervento presentato al 46. convegno Congresso Nazionale della Società Italiana di Microbiologia tenutosi a Palermo nel 2018.
Abstract:
Introduction
-
Biofilm
-
formation and fungal filamentation are well
-
recognized virulence factors in
Candida
pathogenesis, helping the fungus to invade host tissues and promoting its persistence.
Modern medicine, characterized by a wide use of biomedical devices, offers new niches for
opportunistic fungi able to form biofilm communities. Conventional anti
fungal drugs have been
demonstrated to be ineffective against biofilms, and alternative strategies and/or drug targets are
needed to overcome biofilm
-
dependent resistance.
Recently, some
Bacillus amyloliquefaciens
strains were reported to have probiotic ac
tivity, to be
effective for the biocontrol of multiple plant diseases caused by soil
-
borne fungal pathogens, and to
possess mycotoxin degrading ability. In this study, we evaluated the activity of secondary
metabolites produced by
B. amyloliquefaciens
on
C
andida
albicans
biofilm.
Materials and Methods
–
C. albicans
SC5314, a strong biofilm producer, was used in this study.
Bacterial supernatants were obtained by centrifuging 48
-
and 72h
-
old
B. amyloliquefaciens
(
Ba
)
,
strain TITI
,
broth cultures. Biofilm f
ormation was induced by sub
-
culturing
C. albicans
in a
defined medium in 96
-
well plate, for total biomass measurement by crystal violet staining, and on
18
-
mm
-
diameter round coverslips, for confocal laser
-
scanning microscope (CLSM) analysis. Gene
expressio
n of hyphal wall protein 1 (
HWP1
) and agglutinin
-
like sequence 3 (ALS
-
3), known to be
relevant for
C. albicans
filamentation and biofilm
-
formation, was investigated by real
-
time PCR.
Results
-
We observed a dramatic inhibition of
C. albicans
ability to adhere to polystyrene surface
by both 48
-
and 72h
-
old
Ba
supernatants. Moreover,
Ba
supernatants applied to 24
-
h preformed
biofilms resulted in the detachment of most cells from the wells.
CLSM analysis with calcofluor white staining, targeting
fungal chitin, showed alterations in
morphology of the growing yeast that resulted in stubby hyphae unable to express typical
thigmotrophic features. HWP
-
1 and ALS
-
3 were downregulated in the presence of
Ba
supernatant.
Discussion and Conclusions
-
Bacill
us
species are good producers of antimicrobial substances
such as peptide and lipopeptide antibiotics, and bacteriocins that have become a highly effective
alternative to traditional fungicides against environmental molds.
Ba
cyclic lipopeptides seem to
be
long to the surfactin, iturin and fengycin families that act as biosurfactants, perturbating fungal
membranes. Our data demonstrate that such compounds could be also effective against medically
relevant yeasts and could have potential uses in biotechnology
and biopharmaceutical applications.
Tipologia IRIS:
14 - Intervento a convegno non pubblicato
Elenco autori:
G. Bassanini, F. Borgo, E. Ottaviano, G. Morace, E. Borghi
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