An essential factor to the virulence of the genus
Candida
is the ability to produce enzymes and this
may be crucial in the establishment of fungal infections.
Aim: This study investigated
in vitro
enzymatic activities of
Candida species and their virulence in an
in vivo Galleria mellonella
experimental model.
Methods: Twenty-four clinical strains of
Candida spp. isolated from the
human oral cavity were evaluated, including the following species:
C. albicans, C. dubliniensis, C.
glabrata, C. tropicalis, C. krusei, C. parapsilosis, C. norvegensis, C. lusitaniae and C. guilliermondii.
All
Candida strains were tested in vitro for production of proteinase and phospholipase. The
Candida strains were also injected into
Galleria mellonella larvae to induce experimental candidiasis,
and after 24 hours, the survival rate was assessed.
Results: Phospholipase and proteinase
activity were observed in 100% of the
C. albicans strains. In the non-
albicans species, proteinase
and phospholipase activity were observed in 25 and 43% of the studied strains, respectively. The
most pathogenic
Candida species in
G. mellonella were
C. albicans, C. dubliniensis and
C.
lusitaniae, whereas
C. glabrata was the least virulent species. Furthermore, a positive significant
correlation was found between both enzymatic activities with virulence in
G. mellonella.
Conclusions: The virulence of
Candida strains in
G. mellonella is related to the quantity of
proteinases and phospholipases production of each strain.
