Lawsonia Inermis-mediated Synthesis Of Silver Nanoparticles: Activity Against Human Pathogenic Fungi And Bacteria With Special Reference To Formulation Of An Antimicrobial Nanogel.

Lawsonia inermis mediated synthesis of silver nanoparticles (Ag-NPs) and its efficacy against Candida albicans, Microsporum canis, Propioniabacterium acne and Trichophyton mentagrophytes is reported. A two-step mechanism has been proposed for bioreduction and formation of an intermediate complex leading to the synthesis of capped nanoparticles was developed. In addition, antimicrobial gel for M. canis and T. mentagrophytes was also formulated. Ag-NPs were synthesized by challenging the leaft extract of L. inermis with 1 mM AgNO₃. The Ag-NPs were characterized by Ultraviolet-Visible (UV-Vis) spectrophotometer and Fourier transform infrared spectroscopy (FTIR). Transmission electron microscopy (TEM), nanoparticle tracking and analysis sytem (NTA) and zeta potential was measured to detect the size of Ag-NPs. The antimicrobial activity of Ag-NPs was evaluated by disc diffusion method against the test organisms. Thus these Ag-NPs may prove as a better candidate drug due to their biogenic nature. Moreover, Ag-NPs may be an answer to the drug-resistant microorganisms.

In vitro antifungal drug susceptibilities of dermatophytes microconidia and arthroconidia

Objectives: Arthroconidia have been considered as the primary cause of infection by dermatophytes. However, the in vitro antifungal testing evaluates the responses mainly of microconidia or hyphae, and dermatophytes in vivo often produce arthroconidia, a cellular structure presumably more resistant to antifungals. The aim of this study was to compare the in vitro susceptibility of microconidia and arthroconidia of Trichophyton rubrum, Trichophyton tonsurans and Trichophyton equinum to griseofulvin, itraconazole, terbinafine, fluconazole, amphotericin B and hygromycin B. Methods: Microconidia and arthroconidia were produced in vitro, and their susceptibility to each drug was evaluated by assessing the CLSI M38-A broth microdilution method. Results: Arthroconidia of all strains analysed appeared to be more resistant to fluconazole, griseofulvin and itraconazole than microconidia. The MIC of terbinafine was the same for microconidia and arthroconidia for all strains, and the MIC of amphotericin B for microconidia and arthroconidia was the same for isolates of T. equinum and T. tonsurans, but differed for T. rubrum. Finally, the level of resistance of microconidia for all strains towards the antibiotic hygromycin B was from 25 to 400 mg/L. Conclusions: The difference in the susceptibility between microconidia and arthroconidia depends on the drug and on the strain, and may be one of the causes of therapeutic failure. Also, the level of resistance to the antibiotic hygromycin B presented by microconidia of these isolates will allow the use of hygromycin resistance as a dominant marker in fungal transformation procedures in future studies of gene function.

Dermatophyte agents in the city of São Paulo, from 1992 to 2002

Dermatophytosis are superficial mycoses caused by fungi that can invade stratum corneum and keratinized tissues. In order to study the frequency of dermatophytes species and the clinical manifestations caused by these fungi, in São Paulo, SP, Brazil, the authors analyzed cultures isolated at the Mycology Laboratory from a selected population (15,300 out-patients of the Hospital das Clínicas, Department of Dermatology, Faculty of Medicine of University of São Paulo) from January 1992 to June 2002. The most prevalent dermatophyte was Trichophyton rubrum (48.7%), followed by Microsporum canis (20.9%), Trichophyton tonsurans (13.8%), Trichophyton mentagrophytes (9.7%), Epidermophyton floccosum (4.1%), and Microsporum gypseum (2.5%). These agents determined more than one clinical manifestation, i.e., tinea corporis (31.5%), tinea capitis (27.5%), tinea unguium (14.8%), tinea cruris (13.9%), tinea pedis (9.9%), and tinea manuum (1.9%). Clinical variants of dermatophytosis and their relationship to the etiologic agents were studied and the results were compared to those obtained in previous studies in other regions of Brazil and in other countries.

Dermatophyte susceptibilities to antifungal azole agents tested in vitro by broth macro and microdilution methods

The in vitro susceptibility of dermatophytes to the azole antifungals itraconazole, fluconazole and ketoconazole was evaluated by broth macro and microdilution methods, according to recommendations of the CLSI, with some adaptations. Twenty nail and skin clinical isolates, four of Trichophyton mentagrophytes and 16 of T. rubrum were selected for the tests. Itraconazole minimal inhibitory concentrations (MIC) varied from < 0.03 to 0.25 µg/mL in the macrodilution and from < 0.03 to 0.5 µg/mL in the microdilution methods; for fluconazole, MICs were in the ranges of 0.5 to 64 µg/mL and 0.125 to 16 µg/mL by the macro and microdilution methods, respectively, and from < 0.03 to 0.5 µg/mL by both methods for ketoconazole. Levels of agreement between the two methods (± one dilution) were 70% for itraconazole, 45% for fluconazole and 85% for ketoconazole. It is concluded that the strains selected were inhibited by relatively low concentrations of the antifungals tested and that the two methodologies are in good agreement especially for itraconazole and ketoconazole.

In vitro susceptibility testing of dermatophytes isolated in Goiania, Brazil, against five antifungal agents by broth microdilution method

The antifungal activities of fluconazole, itraconazole, ketoconazole, terbinafine and griseofulvin were tested by broth microdilution technique, against 60 dermatophytes isolated from nail or skin specimens from Goiania city patients, Brazil. In this study, the microtiter plates were incubated at 28 ºC allowing a reading of the minimal inhibitory concentration (MIC) after four days of incubation for Trichophyton mentagrophytes and five days for T. rubrum and Microsporum canis. Most of the dermatophytes had uniform patterns of susceptibility to the antifungal agents tested. Low MIC values as 0.03 µg/mL were found for 33.3%, 31.6% and 15% of isolates for itraconazole, ketoconazole and terbinafine, respectively.

ANTIFUNGAL POTENTIAL OF PLANT SPECIES FROM BRAZILIAN CAATINGA AGAINST DERMATOPHYTES

Trichophyton rubrum and Trichophyton mentagrophytes complex, or Trichophyton spp. are the main etiologic agents of dermatophytosis, whose treatment is limited by the high cost of antifungal treatments, their various side effects, and the emergence of resistance amongst these species. This study evaluated the in vitro antidermatophytic activity of 23 crude extracts from nine plant species of semiarid vegetation (caatinga) found in Brazil. The extracts were tested at concentrations ranging from 1.95 to 1,000.0 mg/mL by broth microdilution assay against the reference strains T. rubrum ATCC 28189 and T. mentagrophytesATCC 11481, and 33 clinical isolates of dermatophytes. All plants showed a fungicidal effect against both fungal species, with MIC/MFC values of the active extracts ranging from 15.6 to 250.0 µg/mL. Selected extracts of Eugenia uniflora (AcE), Libidibia ferrea (AE), and Persea americana (AcE) also exhibited a fungicidal effect against all clinical isolates of T. rubrum and T. mentagrophytes complex. This is the first report of the antifungal activity of Schinus terebinthifolius, Piptadenia colubrina, Parapiptadenia rigida, Mimosa ophthalmocentra, and Persea americana against both dermatophyte species.

Dermatofitoses no meio urbano e a coexistência do homem com cães e gatos

Foram submetidos a exame clínico laboratorial de dermatofitose e inqueridos sobre o possível contato com cães e gatos 158 pacientes residentes na área urbana de Fortaleza, que apresentavam lesões suspeitas de dermatofitose. Esta busca associada aos dados obtidos em questionário permitiram identificar a freqüência de surtos domiciliares. Dentre os 83 dermatófitos isolados de infecções humanas, predominaram as espécies antropofílicas sobre as zoofílicas, tendo sido observado uma confluência de diagnóstico humano e animal em 100% dos casos de dermatofitoses zoofílicas humanas, onde foram identificadas as mesmas espécies no homem e nos animais contactantes: Microsporum canis e Trichophyton mentagrophytes. Já os pacientes portadores de dermatófitos antropofílicos variaram quanto ao contato com animais domésticos, não tendo sido isolado estes fungos de nenhum animal contactante. Diante da baixa freqüência de dermatofitoses zoofílicas, considerou-se que o convívio do homem com cães e gatos domésticos foi pouco representativo como fator condicionante da ocorrência de dermatofitoses no meio urbano.

Etiologia e epidemiologia das dermatofitoses em Goiânia, GO, Brasil

As dermatofitoses são infecções superficiais capazes de produzir lesões em tecidos queratinizados, como pele, pêlo e unhas. Foram examinados 6068 indivíduos procedentes de Goiânia, com suspeita clínica de infecções fúngicas, durante 5 anos (1993-1997), verificando-se a incidência e a etiologia das dermatofitoses nos referidos pacientes. Material coletado de várias regiões corpóreas permitiu caracterizar 1595 dermatófitos em 1345 indivíduos. A identificação dos dermatófitos realizada através de cultivo em ágar Sabouraud e microcultivo em lâmina, permitiu verificar uma maior freqüência de Trichophyton rubrum (37,4%), T. mentagrophytes (36,4%) e Microsporum canis (16%). Os dermatófitos foram mais freqüentemente encontrados produzindo lesões nos pés (30,5%), região inguino crural (17,8%) e região glabra do corpo (15,5%). Foi analisada a distribuição corporal das lesões de dermatofitoses com os respectivos agentes etiológicos encontrados. Melhores condições higiênicas e diagnóstico precoce da doença são necessários para controlar e diminuir a incidência de dermatofitoses na nossa região.

Epidemiologia e etiologia das dermatofitoses em Goiânia, GO, Brasil

Os dermatófitos são um grupo de fungos taxonomicamente relacionados que têm a capacidade de invadir os tecidos queratinizados (pele, pêlo e unha) dos homens e animais produzindo infecções denominadas dermatofitoses. Com o intuito de avaliar a epidemiologia e etiologia das infecções causadas por estes fungos em Goiânia, GO, foram examinadas no Laboratório de Micologia do Instituto de Patologia Tropical e Saúde Pública da Universidade Federal de Goiás, de janeiro a dezembro de 1999, 1.955 amostras de indivíduos com suspeita clínica de dermatofitoses. Foram isolados 445 (22,8%) cepas de dermatófitos e identificados principalmente Trichophyton rubrum (49,4%), Trichophyton mentagrophytes (30,8%) e Microsporum canis (12,6%). Quanto à localização das lesões, os membros inferiores, unhas dos pés e couro cabeludo foram as regiões mais acometidas. Neste estudo foram avaliados dados correlacionados a sexo, faixa etária, local das lesões e agente etiológico.

Tinha do couro cabeludo em crianças de Goiânia, Brasil

Durante o período de janeiro de 1999 a julho de 2002 um total de 164 casos de tinha do couro cabeludo foram diagnosticados através de exames micológicos, realizados no Instituto de Patologia Tropical e Saúde Pública da Universidade Federal de Goiás. Destes pacientes, 94 (57,3%) pertenciam ao sexo masculino, com idades variando de 3 meses a 13 anos. O diagnóstico e identificação dos agentes de dermatofitoses do couro cabeludo foram feitos utilizando-se exame direto com KOH a 20% e cultivo em ágar Mycobiotic e em ágar Sabouraud dextrose acrescido de cloranfenicol. As seguintes espécies foram identificadas: Microsporum canis (71,3%), Trichophyton tonsurans (11%), Trichophyton mentagrophytes (7,9%), Trichophyton rubrum (6,7%) and Microsporum gypseum (3%). Nossos estudos mostraram que o fungo de habitat natural no animal (zoofílico), Microsporum canis foi o agente mais comum de lesões no couro cabeludo em humanos.

Ocorrência de dermatófitos em amostras de unhas, pés e mãos coletadas de estudantes universitários

Este trabalho teve como objetivo, avaliar a presença de dermatófitos, especificamente em unhas, pés e mãos de estudantes universitários com e sem lesões sugestivas de dermatofitose. Foram coletadas 280 amostras dessas regiões, das quais 31 (11,1%) apresentaram positividade apenas pelo exame direto, e 20 (7,1%) tiveram, além do exame direto positivo, crescimento de dermatófito, mediante cultivo da amostra biológica. T. rubrum foi o dermatófito isolado com maior freqüência (80%), seguido por T. mentagrophytes (20%). Considerando os sítios analisados neste trabalho, a ocorrência de dermatófitos foi observada em 10,4% nas unhas dos pés, 5% nas escamas de pés, 2,5% nas unhas das mãos e apenas 0,4% nas escamas das mãos.

Tinea capitis among children at one suburban primary school in the City of Maputo, Mozambique

This study evaluated the prevalence of Tinea capitis among schoolchildren at one primary school and also identified the causative agents. Scalp flakes were collected from children presenting clinical signs suggestive of Tinea capitis. Dermatophytes were identified by following standard mycological procedures. This study found a clinical prevalence of Tinea capitis of 9.6% (110/1149). The dermatophytes isolated were Microsporum audouinii, Trichophyton violaceum, and Trichophyton mentagrophytes. The most prevalent causative agent in this study was Microsporum audouinii, thus confirming the findings from previous cross-sectional studies carried out in the city of Maputo.

Epidemiologia, etiologia e formas clínicas das dermatofitoses em Pernambuco, 1995-2005

Num total de 1.238 casos de dermatofitoses, ocorridas na Cidade de Recife /PE, observou-se predomínio das tinhas de couro cabeludo (33,7%) e Trichophyton tonsurans (25,5%), entre 1995 e 1999, enquanto as tinhas de pele glabra (35,5%) e Trichophyton rubrum (34%) foram mais freqüentes entre 2000 e 2005. Detectou-se importante redução do Trichophyton mentagrophytes, no último período.

Comparison of in vitro activity of five antifungal agents against dermatophytes, using the agar dilution and broth microdilution methods

The purpose of this study was to compare the agar dilution and broth microdilution methods for determining the minimum inhibitory concentration (MIC) of fluconazole, itraconazole, ketoconazole, griseofulvin and terbinafine for 60 dermatophyte samples belonging to the species Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum canis. The percentage agreement between the two methods, for all the isolates with < 2 dilutions that were tested was 91.6% for ketoconazole and griseofulvin, 88.3% for itraconazole, 81.6% for terbinafine and 73.3% for fluconazole. One hundred percent agreement was obtained for Trichophyton mentagrophytes isolates evaluated with ketoconazole and griseofulvin. Thus, until a reference method for testing the in vitro susceptibility of dermatophytes is standardized, the similarity of the results between the two methods means that the agar dilution method may be useful for susceptibility testing on these filamentous fungi.

Chemical composition and antifungal activity of essential oil from Eucalyptus smithii against dermatophytes

ABSTRACT INTRODUCTION: In this study, we evaluated the chemical composition of a commercial sample of essential oil from Eucalyptus smithii R.T. Baker and its antifungal activity against Microsporum canis ATCC 32903, Microsporum gypseum ATCC 14683, Trichophyton mentagrophytes ATCC 9533, T. mentagrophytes ATCC 11480, T. mentagrophytes ATCC 11481, and Trichophyton rubrum CCT 5507. METHODS: Morphological changes in these fungi after treatment with the oil were determined by scanning electron microscopy (SEM). The antifungal activity of the oil was determined on the basis of minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values. RESULTS: The compound 1,8-cineole was found to be the predominant component (72.2%) of the essential oil. The MIC values of the oil ranged from 62.5μg·mL−1 to >1,000μg·mL−1, and the MFC values of the oil ranged from 125μg·mL−1 to >1,000μg·mL−1. SEM analysis showed physical damage and morphological alterations in the fungi exposed to this oil. CONCLUSIONS: We demonstrated the potential of Eucalyptus smithii essential oil as a natural therapeutic agent for the treatment of dermatophytosis.