Chemical composition, toxicological aspects and antifungal activity of essential oil from Lippia sidoides Cham

OBJECTIVES

The aims of this study were to test the essential oil from Lippia sidoides Cham. for antifungal activity, in vitro, against Candida spp. and Microsporum canis, to evaluate its acute and subchronic toxicological effects, in vivo, and to determine its chemical constituents.

METHODS

The antifungal activity, in vitro, was initially evaluated by the agar-well diffusion technique, and the MIC and minimum fungicidal concentration (MFC) were determined by the broth microdilution method. The acute and subchronic toxicological effects were determined in mice and rats, respectively. The chemical composition of the essential oil was determined by gas chromatography coupled to mass spectroscopy.

RESULTS

The essential oil obtained from L. sidoides was effective against all tested strains by the agar-well diffusion method. The MICs of L. sidoides essential oil for strains of M. canis ranged from 4 to 70 mg/L and the MFCs ranged from 9 to 150 mg/L. The MICs for strains of Candida spp. ranged from 620 to 2500 mg/L and the MFCs ranged from 1250 to 5000 mg/L. The main constituents of L. sidoides essential oil were thymol (59.65%), E-caryophyllene (10.60%) and p-cymene (9.08%). The acute administration of the essential oil up to 3 g/kg by the oral route to mice was devoid of overt toxicity. The 30 day oral administration of L. sidoides oil (117.95 mg/kg/day) to rats did not induce any significant histopathological, haematological or serum biochemical alterations.

CONCLUSIONS

The essential oil from L. sidoides may be a promising source in the search for new antifungal drugs due to its efficacy and low toxicity.

Antifungal effects of the flavonoids kaempferol and quercetin: a possible alternative for the control of fungal biofilms

This study aimed to determine the minimum inhibitory concentration (MIC) of kaempferol and quercetin against planktonic and biofilm forms of the Candida parapsilosis complex. Initially, nine C. parapsilosis sensu stricto, nine C. orthopsilosis and nine C. metapsilosis strains were used. Planktonic susceptibility to kaempferol and quercetin was assessed. Growing and mature biofilms were then exposed to the flavonoids at MIC or 10xMIC, respectively, and theywere also analyzed by confocal laser scanning microscopy. The MIC ranges were 32-128 µg ml^-1 for kaempferol and 0.5-16 µg ml^-1 for quercetin. Kaempferol and quercetin decreased (P < 0.05) the metabolic activity and biomass of growing biofilms of the C. parapsilosis complex. As for mature biofilms, the metabolic effects of the flavonoids varied, according to the cryptic species, but kaempferol caused an overall reduction in biofilm biomass. Microscopic analyses showed restructuring of biofilms after flavonoid exposure. These results highlight the potential use of these compounds as sustainable resources for the control of fungal biofilms.

Central nervous system involvement in dengue: a study in fatal cases from a dengue endemic area

OBJECTIVE

This study aimed to determine the frequency of CNS infection by dengue virus (DENV) in individuals with fatal outcomes.

METHODS

Samples of 150 individuals suspect of an infection disease and with fatal outcomes were investigated for evidence of the presence of DENV. The sampling was made up of 150 CSF, 120 tissue samples, and 109 blood specimens. The tests used were viral isolation, reverse transcriptase PCR, immunohistochemistry, nonstructural 1 antigen, and immunoglobulin M detection.

RESULTS

Out of 150 studied patients, 84 were dengue positive. Evidence of the presence of DENV was found in 41 CSF, showing the following neurologic diagnosis: 46.3% encephalitis, 34.1% meningoencephalitis, and 19.5% meningitis, giving a frequency of 48.8% of the 84 dengue-positive cases. The major clinical manifestations observed on these individuals were fever, headache, mental irritability, breathless, vomiting, muscle pain, tiredness, abdominal pain, somnolence, restlessness, dizziness, cough, seizure, coma, and neck stiffness.

CONCLUSION

Clinical manifestations and laboratory-positive results in CSF that may indicate the presence of DENV led to consider the invasion of CNS by DENV in these fatal cases studied, and showed that neurologic pathology was an important fatal complication in dengue cases.

Chemical composition, toxicity and larvicidal and antifungal activities of Persea americana (avocado) seed extracts

The present study had the aim of testing the hexane and methanol extracts of avocado seeds, in order to determine their toxicity towards Artemia salina, evaluate their larvicidal activity towards Aedes aegypti and investigate their in vitro antifungal potential against strains of Candida spp, Cryptococcus neoformans and Malassezia pachydermatis through the microdilution technique. In toxicity tests on Artemia salina, the hexane and methanol extracts from avocado seeds showed LC50 values of 2.37 and 24.13 mg mL-1 respectively. Against Aedes aegypti larvae, the LC50 results obtained were 16.7 mg mL-1 for hexane extract and 8.87 mg mL-1 for methanol extract from avocado seeds. The extracts tested were also active against all the yeast strains tested in vitro, with differing results such that the minimum inhibitory concentration of the hexane extract ranged from 0.625 to 1.25mg L-(1), from 0.312 to 0.625 mg mL-1 and from 0.031 to 0.625 mg mL-1, for the strains of Candida spp, Cryptococcus neoformans and Malassezia pachydermatis, respectively. The minimal inhibitory concentration for the methanol extract ranged from 0.125 to 0.625 mg mL-1, from 0.08 to 0.156 mg mL-1 and from 0.312 to 0.625 mg mL-1, for the strains of Candida spp., Cryptococcus neoformans and Malassezia pachydermatis, respectively.

Onychomycosis in Ceará (Northeast Brazil): epidemiological and laboratory aspects

Knowledge of epidemiological and mycological characteristics of onychomycosis has been noted by many authors as being an important tool for control of these fungal infections. This study seeks to improve knowledge of onychomycosis epidemiology and mycological features. Samples were taken from infected fingernails and toenails of 976 patients undergoing treatment at a respected Dermatology Center in Ceará, Fortaleza, CE, Brazil. Specimens from 512 patients (52%) were positive for onychomycosis. From the culture-positive samples, yeasts of the genus Candida (C. albicans, C. tropicalis, C. krusei, C. parapsilosis) were dominant. The dermatophytes isolated (Trichophyton rubrum, T. tonsurans, T. mentagrophytes var. mentagrophytes) were dominant in 46 patients (12.99%). The mould Fusarium spp. was isolated from 29 patients (8.19%). Yeast of the genus Candida is the main causal factor in onychomycosis in our region. Also, the study showed the importance of performing direct examination and culture in diagnosis of onychomycosis.

Candidemia in a Brazilian hospital: the importance of Candida parapsilosis

The aim of this study was to perform a retrospective analysis of cases of candidemia in a Brazilian hospital in the city of Fortaleza, Ceará. A total of 50 blood cultures were analyzed from 40 candidemic patients. The mycological diagnosis was based on the phenotypical analysis and the patients' data were recorded in appropriate files. The most frequent species were Candida parapsilosis (n = 18), followed by C. albicans (n = 14), C. tropicalis (n = 8), C. guillermondii (n = 6), C. glabrata (n = 2), and Candida spp. (n = 2). A detailed descriptive study was undertaken with 21 patients whose medical records were complete. The candidemia episodes occurred in eight male patients and 13 female patients. The most representative risk factors implicated in candidemia were prior antibiotic therapy, central venous catheters, parenteral nutrition, gastric probes and mechanical ventilation. Death occurred in 13 of the 21-candidemic patients. This study demonstrated the emergence of candidemia caused by C. parapsilosis in a Brazilian hospital in the city of Fortaleza, Ceará.

Molecular methods for the diagnosis and characterization of Cryptococcus: a review

Cryptococcosis is a fungal infection caused by yeasts of the genus Cryptococcus, with Cryptococcus neoformans and Cryptococcus gattii as the primary pathogenic species. This disease is a threat to immunocompromised patients, especially those who have AIDS. However, the disease has also been described in healthy individuals. The tests used to identify these microorganisms have limitations that make final diagnosis difficult. However, currently there are specific gene sequences that can be used to detect C. neoformans and C. gattii from clinical specimens and cultures. These sequences can be used for identification, typing, and the study of population genetics. Among the main identification techniques are hybridization, which was the pioneer in molecular identification and development of specific probes for pathogen detection; PCR and other PCR-based methods, particularly nested PCR and multiplex PCR; and sequencing of specific genomic regions that are amplified through PCR, which is especially useful for diagnosis of cryptococcosis caused by unconventional Cryptococcus sp. Concerning microorganism typing, the following techniques have shown the best ability to differentiate between fungal serotypes and molecular types: PCR fingerprinting, PCR-RFLP, AFLP, and MLST. Thus, the accumulation of data generated by molecular methods can have a positive impact on monitoring resistant strains and treating diseases.

Detection of the dengue non-structural 1 antigen in cerebral spinal fluid samples using a commercially available enzyme-linked immunosorbent assay

The involvement of the central nervous system in dengue infections has been reported in countries where the disease in endemic. The purpose of this study was to determine whether an enzyme-linked immunosorbent assay kit designed to detect the dengue NS1 antigen in serum was able to detect this antigen in cerebral spinal fluid (CSF) samples from patients with fatal outcomes. To evaluate the sensitivity of the kit, 26 dengue-positive CSF samples were used. The Pan-E Dengue Early kit was able to detect the NS1 antigen in 13 of 26 dengue-positive CSF samples, resulting in a sensitivity of 50% (95% confidence interval, 29.9-70.1%) and specificity of 100% (95% confidence interval, 75.3-100%). The kit was able to detect the NS1 antigen in CSF of individuals who had died of dengue. When used in combination with IgM, the detection rate rose to 92.3%. This study reports a method for rapidly detecting the dengue virus in CSF, thereby increasing the diagnosis of dengue fever cases with unusual neurological manifestations.

Quantitative and structural analyses of the in vitro and ex vivo biofilm-forming ability of dermatophytes

PURPOSE

The aim of this study was to evaluate the in vitro and ex vivo biofilm-forming ability of dermatophytes on a nail fragment.

METHODOLOGY

Initially, four isolates of Trichophyton rubrum, six of Trichophyton tonsurans, three of Trichophyton mentagrophytes, ten of Microsporum canis and three of Microsporum gypseum were tested for production biomass by crystal violet assay. Then, one strain per species presenting the best biofilm production was chosen for further studies by optical microscopy (Congo red staining), confocal laser scanning (LIVE/DEAD staining) and scanning electron (secondary electron) microscopy.

RESULTS

Biomass quantification by crystal violet assay, optical microscope images of Congo red staining, confocal microscope and scanning electron microscope images revealed that all species studied are able to form biofilms both in vitro and ex vivo, with variable density and architecture. M. gypseum, T. rubrum and T. tonsurans produced robust biofilms, with abundant matrix and biomass, while M. canis produced the weakest biofilms compared to other species.

CONCLUSION

This study sheds light on biofilms of different dermatophyte species, which will contribute to a better understanding of the pathophysiology of dermatophytosis. Further studies of this type are necessary to investigate the processes involved in the formation and composition of dermatophyte biofilms.

Twelve years of coccidioidomycosis in Ceará State, Northeast Brazil: epidemiologic and diagnostic aspects

Coccidioidomycosis is an endemic infection in the Americas caused by the dimorphic fungi Coccidioides immitis and Coccidioides posadasii. Although the disease occurs in Brazil in sporadic form, little information about these cases is available. In this study, we summarize the most important clinical, epidemiologic, and diagnostic features of coccidioidomycosis in Ceará State (Northeast Brazil) during the past 12 years. In this period, 19 cases of coccidioidomycosis were diagnosed. All the patients were young males and came from semiarid areas of the state. The majority of cases were associated to armadillo hunting, and pulmonary disease was the most common clinical presentation. In our laboratory, coccidioidomycosis was confirmed by culture, serology, and polymerase chain reaction tests, which together were very suitable for the diagnosis of this disease. Based on our local experience, we believe many cases of this disease are misdiagnosed or not diagnosed in our region. Therefore, some strategies for improvement of diagnosis should be encouraged by local authorities.

Antifungal susceptibility of Sporothrix schenckii complex biofilms

Sporotrichosis, caused by species of Sporothrix schenckii complex, is the most prevalent subcutaneous mycosis in many areas of Latin America. The aim of this study was to evaluate the ability of Sporothrix spp. to form biofilms in vitro and to characterize the growth kinetics, morphology, and antifungal susceptibility of biofilms against classical antifungals. We investigated the ability of strains to produce biofilms in vitro and determined the effects of exposure to amphotericin B, itraconazole, caspofungin, ketoconazole, voriconazole, and fluconazole at minimum inhibitory concentration (MIC) against planktonic form and at 10× MIC and 50× MIC on the biomass and metabolic activity of these biofilms. Biofilm structure was analyzed by optical microscopy using Congo-red staining, confocal and scanning electron microscopy. Strains were classified for biofilm-forming ability, through the analysis of absorbance of crystal violet retained by biomass of mature biofilms. We found that all S. brasiliensis (n = 10), S. schenckii sensu stricto (n = 2), S. globosa (n = 2), and S. mexicana (n = 4) strains were strong biofilm-producers. The analyzed biofilms had dense network of hyphae and conidia immersed in extracellular matrix, with presence of water channels. Antifungal drugs at the three tested concentrations showed different effects on biomass and metabolic activity of biofilms. However, the best inhibitory response was observed with 50× MIC of amphotericin B and caspofungin, which reduced these parameters. Furthermore, high drug concentrations, especially amphotericin B and caspofungin, showed antifungal activity against these biofilms, probably because they damaged the architecture and extracellular matrix, allowing diffusion of the drugs.

Terpinen-4-ol, tyrosol, and β-lapachone as potential antifungals against dimorphic fungi

This study aimed to evaluate the in vitro antifungal activity of terpinen-4-ol, tyrosol, and β-lapachone against strains of Coccidioides posadasii in filamentous phase (n=22) and Histoplasma capsulatum in both filamentous (n=40) and yeast phases (n=13), using the broth dilution methods as described by the Clinical and Laboratory Standards Institute, to determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of these compounds. The mechanisms of action of these compounds were also investigated by analyzing their effect on cell membrane permeability and ergosterol synthesis. The MIC and MFCf these compounds against C. posadasii, mycelial H. capsulatum, and yeast-like H. capsulatum, were in the following ranges: 350-5720μg/mL, 20-2860μg/mL, and 40-1420μg/mL, respectively for terpinen-4-ol; 250-4000μg/mL, 30-2000μg/mL, and 10-1000μg/mL, respectively, for tyrosol; and 0.48-7.8μg/mL, 0.25-16μg/mL, and 0.125-4μg/mL, respectively for β-lapachone. These compounds showed a decrease in MIC when the samples were subjected to osmotic stress, suggesting that the compounds acted on the fungal membrane. All the compounds were able to reduce the ergosterol content of the fungal strains. Finally, tyrosol was able to cause a leakage of intracellular molecules.

In vitro susceptibility of antifungal drugs against Sporothrix brasiliensis recovered from cats with sporotrichosis in Brazil

Sporotrichosis is an important subcutaneous mycosis of humans and animals. Classically, the disease is acquired upon traumatic inoculation of Sporothrix propagules from contaminated soil and plant debris. In addition, the direct horizontal transmission of Sporothrix among animals and the resulting zoonotic infection in humans highlight an alternative and efficient rout of transmission through biting and scratching. Sporothrix brasiliensis is the most virulent species of the Sporothrix schenckii complex and is responsible for the long-lasting outbreak of feline sporotrichosis in Brazil. However, antifungal susceptibility data of animal-borne isolates is scarce. Therefore, this study evaluated the in vitro activity of amphotericin B, caspofungin, itraconazole, voriconazole, fluconazole, and ketoconazole against animal-borne isolates of S. brasiliensis. The susceptibility tests were performed through broth microdilution (M38-A2). The results show the relevant activity of itraconazole, amphotericin B, and ketoconazole against S. brasiliensis, with the following MIC ranges: 0.125-2, 0.125-4 and 0.0312-2 μg/ml, respectively. Caspofungin was moderately effective, displaying higher variation in MIC values (0.25-64 μg/ml). Voriconazole (2-64 μg/ml) and fluconazole (62.5-500 μg/ml) showed low activity against S. brasiliensis strains. This study contributed to the characterization of the in vitro antifungal susceptibility of strains of S. brasiliensis recovered from cats with sporotrichosis, which have recently been considered the main source of human infections.

Detection of Candida species resistant to azoles in the microbiota of rheas (Rhea americana): possible implications for human and animal health

There is growing interest in breeding rheas (Rhea americana) in Brazil. However, there are no data on the yeast microbiota of the gastrointestinal tract of this avian species, and the phenotypic characteristics of these yeasts are not known. Therefore, the aim of this work was to isolate Candida species from the digestive tract of rheas and to evaluate the in vitro antifungal susceptibility and secretion of phospholipases of the recovered isolates. For this purpose, 58 rheas from breeding operations in the cities of Fortaleza and Mossoró, north-eastern Brazil, were used. Samples were gathered from the oropharynx and cloaca of the animals using sterile swabs. Stool samples were collected from their pens by scraping with a scalpel blade. For the primary isolation, the material was seeded onto 2 % Sabouraud dextrose agar supplemented with chloramphenicol (0.5 g l(-1)). The isolates were identified based on morphological and biochemical features. After identification, all the strains were submitted to antifungal susceptibility testing for amphotericin B, itraconazole and fluconazole. The phospholipase activity of the Candida species isolates was also tested by culturing on egg yolk agar. Candida species were isolated from at least one anatomical site in 36/58 birds (14/17 juveniles and 22/41 adults) and in 6/10 faecal samples. Mostly, only a single species was isolated from each collection site (36/56 positive sites), with up to three species being observed only in four cases (4/56). A total of 77 isolates were obtained, belonging to the species Candida parapsilosis sensu lato (19), Candida albicans (18), Candida tropicalis (13), Candida guilliermondii (12), Candida krusei (10) and Candida famata (5). C. albicans was more prevalent in the oropharynx of the juvenile rheas when compared with adult ones (P<0.001). All tested isolates were susceptible to amphotericin B, but 16 isolates were simultaneously resistant to the two azole derivatives (11/18 C. albicans, 1/10 C. krusei, 2/19 C. parapsilosis sensu lato and 2/13 C. tropicalis). C. albicans presented a particularly high resistance rate to fluconazole (15/18) and itraconazole (13/18). Finally, 23/77 strains secreted phospholipases. In summary, healthy rheas carry potentially pathogenic Candida species in their gastrointestinal tract, including azole-resistant strains that secrete phospholipases, and are prone to disseminating them in the environment. Thus, breeding and handling these animals may have some implications for human and animal health.

High rate ofMicrosporum canisfeline and canine dermatophytoses in Northeast Brazil: Epidemiological and diagnostic features

Over a one year period (November 2000-December 2001), clinical specimens from 189 dogs and 38 cats, from the city of Fortaleza, Ceará, Brazil, were examined at the Specialized Medical Mycology Center at the Federal University of Ceará to detect animals with dermatophytoses. The mycological analyses were conducted by direct microscopy and by fungal culture on Sabouraud agar, Sabouraud chloramphenicol agar and Mycosel agar. Dermatophytes were isolated from 27 of the 189 (14.3%) canine specimens and 14 of the 38 (36.8%) feline specimens. The identified dermatophytes were Microsporum canis (95%), M. gypseum (2.5%) and Trichophyton mentagrophytes var. mentagrophytes (2.5%). Microsporum canis was the most common species isolated (92.6% and 100%, for dogs and cats respectively). The percentage of positive direct microscopic examinations of clinical specimens and positive cultures was 61%. There was a high proportion of positive cultures from cats less than 1 year of age, but in dogs no significant differences were detected. There were no significant differences between the sexes. Dermatophytes were more frequently isolated in March, April and May, but no significant differences were detected in the seasonal distribution of canine and feline dermatophytoses.

Farnesol increases the susceptibility of Burkholderia pseudomallei biofilm to antimicrobials used to treat melioidosis

AIMS

The aim of this study was to analyse the in vitro activity of farnesol alone and combined with the antibacterial drugs amoxicillin, doxycycline, ceftazidime and sulfamethoxazole-trimethoprim against Burkholderia pseudomallei biofilms.

METHODS AND RESULTS

Susceptibility was assessed by the broth microdilution test and cell viability was read with the oxidation-reduction indicator dye resazurin. The biofilms were evaluated through three microscopic techniques (optical, confocal and electronic microscopy). The minimum biofilm erradication concentration (MBEC) for farnesol was 75-2400 mmol l(-1). In addition, farnesol significantly reduced the MBEC values for ceftazidime, amoxicillin, doxycycline and sulfamethoxazole-trimethoprim by 256, 16, 4 and 4 times respectively (P < 0·05). Optical, confocal and electronic microscopic analyses of farnesol-treated B. pseudomallei biofilms demonstrated that this compound damages biofilm matrix, probably facilitating antimicrobial penetration in the biofilm structure.

CONCLUSIONS

This study demonstrated the effectiveness of farnesol against B. pseudomallei biofilms and its potentiating effect on the activity of antibacterial drugs, in particular ceftazidime, amoxicillin, doxycycline and sulfamethoxazole-trimethoprim.

SIGNIFICANCE AND IMPACT OF THE STUDY

The intrinsic antimicrobial resistance of B. pseudomallei is a serious challenge for the treatment of melioidosis. Thus, this paper reports the inhibitory potential of farnesol against B. pseudomallei biofilms, as well as highlights the favourable pharmacological interaction of farnesol with antibiotics tested, not only on cell viability, but also in the structural morphology of biofilms.

Malassezia pachydermatis from animals: Planktonic and biofilm antifungal susceptibility and its virulence arsenal

The yeast Malassezia pachydermatis is a component of the microbiota of dogs and cats, however it can cause otitis and seborrheic dermatitis in these animals. The objective of this study was to determine the antifungal susceptibility, and evaluate virulence and pathogenicity of 25 M. pachydermatis strains from animals. Susceptibility to ketoconazole, fluconazole, itraconazole, voriconazole, terbinafine, and amphotericin B was evaluated by broth microdilution assay. In addition, biofilm-forming ability, protease, phospholipase, hemolysin and melanin production and adhesion to epithelial cells by this yeast species were assessed. Finally, strain pathogenicity was investigated using the nematode Caenorhabditis elegans. Concerning the planktonic susceptibility, minimum inhibitory concentrations varied from <0.03 to>64 μg/mL for azole derivatives, 1 to >16 μg/mL for amphotericin B and 0.03 to 0.25 μg/mL for terbinafine. All strains were classified as strong biofilm producers, and ketoconazole, fluconazole and amphotericin B presented the best inhibitory effect against mature biofilms. All fungal isolates produced proteases, whereas 14/25 strains were positive for phospholipase production. Hemolytic activity was not observed and 18/25 strains showed dark pigmentation in the presence of L-DOPA. Regarding adhesion to epithelial cells, a low adhesion rate was observed in 10/12 evaluated strains. C. elegans mortality rate reached 95.9% after 96 h of exposure of the worms to M. pachydermatis. This yeast species produces important virulence factors and presents high pathogenicity, corroborating its clinical importance.

Azole resistance in Candida albicans from animals: Highlights on efflux pump activity and gene overexpression

This study investigated potential mechanisms of azole resistance among Candida albicans from animals, including efflux pump activity, ergosterol content and gene expression. For this purpose, 30 azole-resistant C. albicans strains from animals were tested for their antifungal susceptibility, according to document M27-A3, efflux pump activity by rhodamine 6G test, ergosterol content and expression of the genes CDR1, CDR2, MDR1, ERG11 by RT-qPCR. These strains were resistant to at least one azole derivative. Resistance to fluconazole and itraconazole was detected in 23 and 26 strains respectively. Rhodamine 6G tests showed increased activity of efflux pumps in the resistant strains, showing a possible resistance mechanism. There was no difference in ergosterol content between resistant and susceptible strains, even after fluconazole exposure. From 30 strains, 22 (73.3%) resistant animal strains overexpressed one or more genes. From this group, 40.9% (9/22) overexpressed CDR1, 18.2% (4/22) overexpressed CDR2, 59.1% (13/22) overexpressed MDR1 and 54.5% (12/22) overexpressed ERG11. Concerning gene expression, a positive correlation was observed only between CDR1 and CDR2. Thus, azole resistance in C. albicans strains from animals is a multifactorial process that involves increased efflux pump activity and the overexpression of different genes.

Candida tropicalis from veterinary and human sources shows similar in vitro hemolytic activity, antifungal biofilm susceptibility and pathogenesis against Caenorhabditis elegans

The aim of this study was to evaluate the in vitro hemolytic activity and biofilm antifungal susceptibility of veterinary and human Candida tropicalis strains, as well as their pathogenesis against Caenorhabditis elegans. Twenty veterinary isolates and 20 human clinical isolates of C. tropicalis were used. The strains were evaluated for their hemolytic activity and biofilm production. Biofilm susceptibility to itraconazole, fluconazole, voriconazole, amphotericin B and caspofungin was assessed using broth microdilution assay. The in vivo evaluation of strain pathogenicity was investigated using the nematode C. elegans. Hemolytic factor was observed in 95% of the strains and 97.5% of the isolates showed ability to form biofilm. Caspofungin and amphotericin B showed better results than azole antifungals against mature biofilms. Paradoxical effect on mature biofilm metabolic activity was observed at elevated concentrations of caspofungin (8-64μg/mL). Azole antifungals were not able to inhibit mature C. tropicalis biofilms, even at the higher tested concentrations. High mortality rates of C. elegans were observed when the worms were exposed to with C. tropicalis strains, reaching up to 96%, 96h after exposure of the worms to C. tropicalis strains. These results reinforce the high pathogenicity of C. tropicalis from veterinary and human sources and show the effectiveness of caspofungin and amphotericin B against mature biofilms of this species.