Raimunda Sâmia Nogueira Brilhante

The anatomical distribution and antimicrobial susceptibility of yeast species isolated from healthy dogs.

The aim of this work was to identify the predominant yeast species present at different anatomical sites in healthy dogs and to determine their in vitro antimicrobial susceptibility using a broth microdilution assay. Samples were collected from the preputial, vaginal, oral and perianal mucosae and the isolates cultured were identified according to their morphological characteristics and biochemical profile. Malassezia pachydermatis was the most commonly isolated yeast, followed by Candida parapsilosis, Candida tropicalis, Candida albicans, Saccharomyces cerevisiae and Rhodotorula spp. Minimum inhibitory concentrations of the azole derivatives ketoconazole, itraconazole and fluconazole against Candida spp. were 0.03-16 microg/mL, 0.06 to >16 microg/mL and 0.5-64 microg/mL, respectively and Candida isolates were sensitive to caspofungin and amphotericin B. Although all isolates of M. pachydermatis were sensitive to itraconazole, fluconazole, ketoconazole and amphotericin B, they were found to be resistant to caspofungin. The study has highlighted that Candida spp., M. pachydermatis, S. cerevisiae and Rhodotorula spp. are part of the normal canine surface microbiota and some of these organisms exhibit in vitro resistance to commonly used antimicrobials.

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.O presente estudo teve como objetivo testar os extratos hexânico e metanolico das sementes do abacate, a fim de determinar sua toxicidade em Artemia salina, avaliar a atividade larvicida frente ao Aedes aegypti, bem como verificar o potencial antifungico in vitro contra cepas de Candida spp, Cryptococcus neoformans e Malassezia pachydermatis, atraves da tecnica de microdiluicao. Os extratos hexânico e metanolico das sementes de abacate apresentaram no teste de toxicidade frente a Artemia salina, valores de LC50 2,37 e 24,13mg L-1, respectivamente; contra as larvas do Aedes aegypti os resultados obtidos foram LC50 16,7mg L-1 para o extrato hexânico e 8,87mg L-1 para o extrato metanolico das sementes do abacate. Os extratos testados tambem foram ativos contra todas as cepas de leveduras, testadas in vitro, apresentando diferentes resultados, onde o MIC do extrato hexânico variou de 0,625 a 1,25mg mL-1, de 0,312 a 0,625mg mL-1 e de 0,031 a 0,625mg mL-1 para as cepas de Candida spp., Cryptococcus neoformans e Malassezia pachydermatis, respectivamente. O intervalo de MIC para o extrato metanolico foi de 0,125 a 0,625mg mL-1, 0,08 a 0,156mg mL-1 e de 0,312 a 0,625mg mL-1, para as exemplares de Candida spp., Cryptococcus neoformans e Malassezia pachydermatis, respectivamente.

Tinea capitis in a dermatology center in the city of Fortaleza, Brazil: the role of Trichophyton tonsurans

Background  Over a 3‐year period (March 1999 to March 2002), 944 patients with scalp lesions attended a dermatology reference center in the city of Fortaleza, Ceará, Brazil. Clinical specimens were examined at the Specialized Medical Mycology Center, Federal University of Ceará, Fortaleza‐CE, Brazil, to detect patients with tinea capitis.

Histoplasmosis in HIV-positive patients in Ceará, Brazil: clinical-laboratory aspects and in vitro antifungal susceptibility of Histoplasma capsulatum isolates

This study contains a descriptive analysis of histoplasmosis in AIDS patients between 2006 and 2010 in the state of Ceará, Brazil. Additionally, the in vitro susceptibility of Histoplasma capsulatum isolates obtained during this period was assessed. We report 208 cases of patients with histoplasmosis and AIDS, describing the epidemiological, clinical, laboratory and therapeutic aspects. The in vitro antifungal susceptibility test was carried out by the microdilution method, according to Clinical and Laboratory Standards Institute, with H. capsulatum in the filamentous and yeast phases, against the antifungals amphotericin B, fluconazole, itraconazole, voriconazole and caspofungin. In 38.9% of the cases, histoplasmosis was the first indicator of AIDS and in 85.8% of the patients the CD4 cell count was lower than 100 cells/mm(3). The lactate dehydrogenase levels were high in all the patients evaluated, with impairment of hepatic and renal function and evolution to death in 42.3% of the cases. The in vitro susceptibility profile demonstrated there was no antifungal resistance among the isolates evaluated. There was a significant increase in the number of histoplasmosis cases in HIV-positive patients during the period surveyed in the state of Ceará, northeastern Brazil, but no antifungal resistance among the recovered isolates of H. capsulatum.

Minimum inhibitory concentrations of amphotericin B, azoles and caspofungin against Candida species are reduced by farnesol

The objective of this study was to evaluate the antifungal activity of farnesol and its interaction with traditional antifungals against drug-resistant strains of Candida species. To do so, we studied the minimum in vitro inhibitory concentration (MIC) of amphotericin B (AMB), fluconazole (FLC), itraconazole (ITC), caspofungin (CAS) and farnesol against 45 isolates of Candida spp., i.e., 24 C. albicans, 16 C. parapsilosis and 5 C. tropicalis through the use of the broth microdilution method. Then, the isolates were tested with the combination of farnesol plus drugs to which they were previously found to be resistant. Additionally, the strains were pre-incubated at sub-inhibitory farnesol concentrations and their antifungal susceptibilities were re-evaluated. We found the MIC values for farnesol varied from 4.68-150 µM for Candida spp., with 19 isolates having a MIC > 1 mg/l, 18 a MIC ≥ 64 mg/l, 35 having a MIC ≥ 1 mg/l and 6 isolates a MIC ≥ 2 mg/l or were resistant to AMB, FLC, ITC and CAS, respectively. Significant MIC reductions were observed when farnesol and antifungal drugs were combined (P < 0.05) and when Candida strains were incubated with farnesol (P < 0.05). We conclude that the in vitro effects of farnesol improved the activity of traditional antifungals to which the Candida spp. isolates were resistant. These results support further investigation of the role of farnesol in the balance of the sterol biosynthetic pathway and how it interferes with cell viability.

Dengue in Patients with Central Nervous System Manifestations, Brazil

We investigated the prevalence of dengue in patients with suspected viral meningitis/meningoencephalitis in a dengue-endemic area. Cerebrospinal fluid analysis showed positive results and a 6.74× greater likelihood of identifying positive fluid in patients who died. Our findings support testing patients with neurologic manifestations for the virus in dengue-endemic areas.

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.

Yeasts from Macrobrachium amazonicum: a focus on antifungal susceptibility and virulence factors of Candida spp.

In the present study, it was sought to compare yeast microbiota of wild and captive Macrobrachium amazonicum and evaluate the antifungal susceptibility and production of virulence factors by the recovered isolates of Candida spp. Additionally, cultivation water was monitored for the presence of fungi. Overall, 26 yeast isolates belonging to three genera and seven species were obtained, out of which 24 were Candida spp., with Candida famata as the most prevalent species for both wild and captive prawns. From cultivation water, 28 isolates of filamentous fungi were obtained, with Penicillium spp., Cladosporium spp. and Aspergillus spp. as the most frequent genera. Eight out of 24 Candida spp. isolates were resistant to azole derivatives, out of which four were recovered from wild-harvested prawns. As for production of virulence factors, three (12.5%) and eight (33.3%) isolates presented phospholipase and protease activity, respectively. This is the first comparative study between wild and captive prawns and the first report on yeast microbiota of M. amazonicum. The most relevant finding was the high percentage of resistant Candida spp., including from wild individuals, which suggests the occurrence of an environmental imbalance in the area where these prawns were captured.

Frequency of yeasts and dermatophytes from healthy and diseased dogs.

The aim of this study was to investigate the presence of dermatophytes and yeasts in healthy and diseased dogs. A total of 633 samples were collected from 26 healthy animals (104 samples), 131 with dermatitis (343 samples), 74 with otitais (148 samples), and 19 with ocular diseases (38 samples). Cultures from healthy animals were positive for Malassezia pachydermatis in 13.5% (7/52) of samples from skin, 42.3% (11/26) from ear, and 3.8% (1/26) from eye. Fungal growth was observed in 20.4% (70/343) samples from animals with dermatitis. Microsporum canis was the most isolated fungus (n = 39), followed by M. pachydermatis (n = 30) and Malassezia sp. (n = 3). Of the 148 samples from dogs with otitis, 90 (60.8%) were positive for M. pachydermatis, and of the clinical specimens from the conjunctiva of animals with ophthalmic disease, 2.6% (1/38) presented positive cultures for M. pachydermatis. Only 14.3% (2/14) of the positive cultures for M. pachydermatis and 40.9% (9/22) of those for M. canis were positive in the direct exam. Direct exams were positive in 84.3% (70/83) of the culture positive samples from affected ears of dogs with otitis. Malassezia pachydermatis may act as an aggravating factor in the occurrence of cutaneous diseases, or the isolation of M. canis may be associated with the onset of dermatophytosis. Fungal culture, rather than microscopic examination, should be used as the definitive diagnostic test for dermatomycoses and otitis.

Yeast microbiota of raptors: a possible tool for environmental monitoring

Twenty-two raptors from a rehabilitation centre were evaluated for the presence of yeasts prior to returning them to the wild, and the recovered Candida isolates were tested for in vitro antifungal susceptibility and phospholipase production. Samples were collected from the crop/lower esophagus and cloaca. In vitro antifungal susceptibility and phospholipase production of 21 Candida strains were assessed through broth microdilution and growth on egg yolk agar respectively. Twenty-seven isolates, belonging to seven species, were recovered from 16 tested birds, with C. albicans and C. famata as the most prevalent species. Three out of 21 isolates (2 C. albicans and 1 C. tropicalis) were simultaneously resistant to fluconazole and itraconazole. As for phospholipase production, 8 (8/21) isolates (6 C. albicans, 1 C. famata and 1 C. parapsilosis) showed enzymatic activity. The most relevant finding in this study was the isolation of resistant Candida spp. from wild raptors that had never been submitted to antifungal therapy, which suggests exposure to environmental contaminants. Based on this, we propose the assessment of Candida spp. from the gastrointestinal tract of raptors as a tool for environmental monitoring.