BACKGROUNDSporotrichosis is a subcutaneous mycosis caused by dimorphic pathogenic fungi
belonging to the Sporothrix genus. Pathogenic
Sporothrix species typically produce melanin, which is
known to be a virulence factor.OBJECTIVES The aim of this study was to perform phenotypic, genotypic, and virulence
analyses of two distinct Sporothrix brasiliensis strains
isolated from the same lesion on a patient from Rio de Janeiro.METHODS AND FINDINGS Genotypic analyses by partial sequencing of the calmodulin,
β-tubulin, and chitin synthase genes,
as well as polymerase chain reaction (PCR)-fingerprinting by T3B, M13, and
GACA, showed that the isolates were very similar but not identical. Both
isolates had similar phenotypic characteristics and effectively produced
melanin in their yeast forms, accounting for their ability of causing
disease in a murine sporotrichosis model. Remarkably, isolate B was albino
in its environmental form but caused more severe disease than the pigmented
A isolate.CONCLUSIONS These findings indicate that the patient was infected by two genetically and
biologically distinct S. brasiliensis that vary in their
production of melanin in their environmental forms. The results underscore
the importance of characterizing phenotypically different isolates found in
the same clinical specimen or patient.
Since 1998, the state of Rio de Janeiro, Brazil, has become a public health problem regarding sporotrichosis, a disease caused by Sporothrix spp. involving contact with infected cats. Efforts to isolate these species from environmental sources are not always successful. In our study, soil from residences situated in cities of Rio de Janeiro where cats with sporotrichosis live was collected and cultured an attempt to isolate Sporothrix spp. but it was not successful. However, other saprophytic fungal species were isolated from soil and identified and among them Purpureocillium lilacinum was the most frequent. From there, we decided to study the in vitro interaction of this species with S. brasiliensis, the principal agent that causes sporotrichosis in this state. The results showed that ten isolates of P. lilacinum inhibited the radial mycelial growth of S. brasiliensis with different percentage of inhibition. The interaction between them revealed the pattern described as overgrowth by antagonist. In conclusion, our data suggest that fungal species with very fast growth and capable of producing metabolites could hinder the growth of Sporothrix spp., it also opens the way for the identification of secondary metabolites with biological activity that could be tested against pathogenic fungi.
Purpureocillium lilacinum is a filamentous and hyaline fungus cosmopolitan, saprophytic, largely used in the biological control of plant‐parasitic nematodes and insects, also considered an emerging and opportunistic human pathogen. The standard treatment for hyalohyphomycosis caused by P. lilacinum is not yet defined, since this fungus is resistant to different antifungals, in vitro and in vivo. The aim of this study was to evaluate and compare in vitro antifungal activity against environmental and clinical P. lilacinum isolates and our results demonstrated that these isolates can be resistant to newer generation triazoles, such as voriconazole, and to caspofungin, a drug of the echinocandin class. In summary, we highlight the importance of knowing the different susceptibility profiles of P. lilacinum isolates, and besides that, the emergence of uncommon human and animal opportunistic fungi, such P. lilacinum, especially during COVID‐19, highlight the need for antifungal susceptibility testing of isolates since empirical therapy with different treatment schedules failed in great number of patients.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.