Development and evaluation of an anti-candida cream based on silver nanoparticles.

The ineffectiveness of azole drugs in treating Vulvovaginal Candidiasis (VVC) and Recurrent Vulvovaginal Candidiasis (RVVC) due to antifungal resistance of non-albicans Candida has led to the investigation of inorganic nanoparticles with biological activity. Silver nanoparticles (AgNPs) are important in nanomedicine and have been used in various products and technologies. This study aimed to develop a vaginal cream and assess its in vitro antimicrobial activity against Candida parapsilosis strains, specifically focusing on the synergy between AgNPs and miconazole. AgNPs were synthesized using glucose as a reducing agent and sodium dodecyl sulfate (SDS) as a stabilizer in varying amounts (0.50, 0.25, and 0.10 g). The AgNPs were characterized using UV-Visible (UV-Vis) and Fourier-Transform Infrared (FT-IR) spectroscopies, X-Ray Diffraction (XRD), Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), and Energy Dispersive X-Ray Analysis (EDX). Fifty strains of Candida parapsilosis were used to evaluate the synergistic activity. AgNPs synthesized with 0.5 g SDS had an average size of 77.58 nm and a zeta potential of -49.2 mV, while AgNPs with 0.25 g showed 91.22 nm and -47.2 mV, respectively. AgNPs stabilized with 0.1 g of SDS were not effective. When combined with miconazole, AgNPs exhibited significant antifungal activity, resulting in an average increase of 80% in inhibition zones. The cream developed in this study, containing half the miconazole concentration of commercially available medication, demonstrated larger inhibition zones compared to the commercial samples.

Antifungal Activity of Nanobiocomposite Films Based on Silver Nanoparticles Obtained Through Green Synthesis.

The high incidence of Candida albicans infections has raised concerns regarding side effects and drug resistance, compounded by a limited number of alternative drugs. Silver nanoparticles (AgNPs) have prominent antimicrobial activity, but effective administration remains a challenge. In this study, AgNPs were synthesized via a green chemistry approach, using glucose as a reducing agent, and incorporated into an agar matrix to form a film (AgFilm). The AgNPs and AgFilm were characterized by Ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and atomic force microscopic (AFM). The UV-Vis spectra of the AgNPs and AgFilm showed bands at 415 and 413 nm, respectively. The PXRD and UV-Vis data suggest that the growth of AgNPs was effectively inhibited in the AgFilm. The diameter of AgNPs dispersed in AgFilm was 76 ± 42 nm, and the thickness of the film and 35 ± 3 µm. The antifungal activity of AgFilm was evaluated against 20 strains of C. albicans, demonstrating high antifungal activity with an inhibition zone of 19 ± 2 mm. Therefore, AgFilm could be a promising option for the treatment of superficial C. albicans infections.

Vibrational Spectroscopy and Morphological Studies on Protein-Capped Biosynthesized Silver Nanoparticles.

Silver nanoparticles (AgNPs) have a large number of applications in technology and physical and biological sciences. These nanomaterials can be synthesized by chemical and biological methods. The biological synthesis using fungi represents a green approach for nanomaterial production that has the advantage of biocompatibility. This work studies silver nanoparticles (AgNPs) produced by fungi Rhodotorula glutinis and Rhodotorula mucilaginosa found in ordinary soil of the Universidade Federal do Ceará campus (Brazil). The biosynthesized AgNPs have a protein-capping layer involving a metallic Ag core. The focus of this paper is to investigate the size and structure of the capping layer, how it interacts with the Ag core, and how sensitive the system (core + protein) is to visible light illumination. For this, we employed SEM, AFM, photoluminescence spectroscopy, SERS, and dark-field spectroscopy. The AgNPs were isolated, and SEM measurements showed the average size diameter between 58 nm for R. glutinis and 30 nm for R. mucilaginosa. These values are in agreement with the AFM measurements, which also provided the average size diameter of 85 nm for R. glutinis and 56 nm for R. mucilaginosa as well as additional information about the average size of the protein-capping layers, whose found values were 24 and 21 nm for R. mucilaginosa and R. glutinis nanoparticles, respectively. The protein-capping layer structure seemed to be easily disturbed, and the SERS spectra were unstable. It was possible to identify Raman peaks that might be related to α-helix, ß-sheet, and protein mixed structures. Finally, dark-field microscopy showed that the silver cores are very stable, but some are affected by the laser energy due to heating or melting.

In vitro synergistic activity of lidocaine and miconazole against Candida albicans / Atividade sinérgica in vitro de lidocaína e miconazole contra Candida albicans

Candida albicans is the main yeast isolated from vulvovaginal candidiasis(VVC) and a major antifungal used to treat VVC is miconazole (MZ), it shows local toxic effects, such as irritation and burns. The lidocaine (LD) is a local anesthetic. The aim of this study was to evaluate the synergistic activity of LD/MZ against 19 strains of C. albicans isolated from vaginal secretion. 78.9% of the strains were susceptible to the combination LD/MZ, demonstrating synergism of drugs. These drugs can be used to produce vaginal creams to treat VVC, especially drug resistant.

Candida albicans é a principal levedura isolada de candidíase vulvovaginal (CVV) e o principal antifúngico usado para tratar a VVC é miconazol (MZ), que apresenta efeitos tóxicos locais, tais como irritação e queimaduras. A lidocaína (LD) é um anestésico local. O objetivo deste estudo foi avaliar a atividade sinérgica de LD/MZ contra 19 cepas de C. albicans isoladas de secreção vaginal. Foram suscetíveis à combinação LD/MZ, 78.9% das cepas testadas, demonstrando sinergismo de drogas. Estes fármacos podem ser utilizados para a produção de cremes vaginais para tratar VVC, especialmente aquelas resistentes aos fármacos disponíveis.

SILVER NANOPARTICLES-DISK DIFFUSION TEST AGAINST Escherichia coli ISOLATES.

Nanotechnology can be a valuable ally in the treatment of infections. Silver nanoparticles (AgNPs) are structures that have antimicrobial activity. The aim of this study was to produce AgNPs by green methods, characterize these structures, and assess their antimicrobial activity against Escherichia coli associated with the antibiotic ciprofloxacin. AgNPs were characterized by spectroscopic and microscopic techniques. Antimicrobial activity was evaluated by the disk diffusion method against 10 strains of E. coli. The synthesized AgNPs showed a spherical shape and a size of 85.07 ± 12.86 nm (mean ± SD). AgNPs increased the activity of ciprofloxacin by 40% and may represent a new therapeutic option for the treatment of bacterial infections.

Antifungal activity of silver nanoparticles obtained by green synthesis.

Silver nanoparticles (AgNPs) are metal structures at the nanoscale. AgNPs have exhibited antimicrobial activities against fungi and bacteria; however synthesis of AgNPs can generate toxic waste during the reaction process. Accordingly, new routes using non-toxic compounds have been researched. The proposal of the present study was to synthesize AgNPs using ribose as a reducing agent and sodium dodecyl sulfate (SDS) as a stabilizer. The antifungal activity of these particles against C. albicans and C. tropicalis was also evaluated. Stable nanoparticles 12.5 ± 4.9 nm (mean ± SD) in size were obtained, which showed high activity against Candida spp. and could represent an alternative for fungal infection treatment.

Correlation between microdilution, Etest, and disk diffusion methods for antifungal susceptibility testing of fluconazole against Candida sp. blood isolates.

INTRODUCTION: Antifungal susceptibility testing assists in finding the appropriate treatment for fungal infections, which are increasingly common. However, such testing is not very widespread. There are several existing methods, and the correlation between such methods was evaluated in this study. METHODS: The susceptibility to fluconazole of 35 strains of Candida sp. isolated from blood cultures was evaluated by the following methods: microdilution, Etest, and disk diffusion. RESULTS: The correlation between the methods was around 90%. CONCLUSIONS: The disk diffusion test exhibited a good correlation and can be used in laboratory routines to detect strains of Candida sp. that are resistant to fluconazole.

Perfil de suscetibilidade de Candida tropicalis a antfúngicos sistêmicos / Susceptibility profile of Candida tropicalis to systemic antifungals

Infecções fúngicas invasivas são uma ameaça crescente à saúde humana. Tem ocorrido um aumento considerável na taxa de infecções nosocomiais no sangue, causadas por espécies de Candida. C. albicans é a principal levedura isolada de candidemias, no entanto o isolamento de C. tropicalis e C.parapsilosis também tem sido frequente. Este estudo teve como objetivos isolar, identificar e avaliaro perfil de suscetibilidade de C. tropicalis a antifúngicos sistêmicos. Foram utilizadas 50 cepas de C.tropicalis provenientes de amostras clínicas de sangue, urina e lavado bronco alveolar de pacientes atendidos no Ceará. Foi avaliado o perfil de sensibilidade das cepas aos antifúngicos sistêmicos anfotericina B, fluconazol, itraconazol e voriconazol pela metodologia de microdiluição em caldoRPMI. As cepas de C. tropicalis não apresentaram resistência, mas foram encontradas cepas com CIM elevada para o fluconazol, portanto deve ter continuidade o monitoramento de Candida spp. isoladas no Ceará com o fim de avaliar a evolução da resistência.

Correlation between microdilution, Etest, and disk diffusion methods for antifungal susceptibility testing of fluconazole against Candida sp. blood isolates

INTRODUCTION: Antifungal susceptibility testing assists in finding the appropriate treatment for fungal infections, which are increasingly common. However, such testing is not very widespread. There are several existing methods, and the correlation between such methods was evaluated in this study. METHODS: The susceptibility to fluconazole of 35 strains of Candida sp. isolated from blood cultures was evaluated by the following methods: microdilution, Etest, and disk diffusion. RESULTS: The correlation between the methods was around 90%. CONCLUSIONS: The disk diffusion test exhibited a good correlation and can be used in laboratory routines to detect strains of Candida sp. that are resistant to fluconazole.

Avaliação da qualidade microbiológica de água de coco comercializada em Fortaleza, CE / Evaluation of microbiological quality of coconut water commercialized in Fortaleza, Brazil

A adesão crescente a um estilo de vida mais saudável e a manutenção de boa forma do corpo vem impulsionando o aumento da procura de parcela da população a alternativas naturais para a alimentação. O objetivo desta pesquisa foi avaliar microbiologicamente as águas de coco comercializadas na cidade de Fortaleza. Neste estudo foram analisadas 30 amostras de água de coco comercializadas em diversos pontos de venda da cidade de Fortaleza. Em todas as amostras foram verificadas a presença de coliformes totais. Também foi verificada a presença de colônias de mesófilos e bolores e leveduras. Nenhuma amostra apresentou coliformes fecais. Foi constatado que 96,66% das amostras de água de coco analisadas estão impróprias para o consumo.

Identificação molecular e suscetibilidade antifúngica de Candida parapsilosis isoladas no Ceará, Brasil / Molecular identification and antifungal susceptibility of Candida parapsilosis isolates in Ceará, Brazil

INTRODUÇÃO: Candida parapsilosis é a segunda ou terceira levedura mais isolada de hemoculturas em várias partes do mundo. É um patógeno comumente isolado no Brasil e no Ceará. Apresenta capacidade de formar biofilmes em cateteres e outros dispositivos médicos e esses fatores contribuem para a disseminação dessa levedura. OBJETIVOS: Identificar e avaliar a suscetibilidade aos antifúngicos de C. parapsilosis isoladas de amostras de sangue e urina de pacientes atendidos em hospitais no Ceará. MÉTODOS: Foram isoladas e identificadas 57 cepas de C. parapsilosis. As cepas foram identificadas por testes fenotípicos e moleculares. A suscetibilidade foi avaliada pelo método de microdiluição em caldo (protocolo do Clinical and Laboratory Standards Institute [CLSI] M27-A3). Foram avaliados cinco antifúngicos (anfotericina B, caspofungina, fluconazol, itraconazol e voriconazol). RESULTADOS E CONCLUSÃO: As cepas foram identificadas como C. parapsilosis por testes fenotípicos e confirmadas pelos testes moleculares. Quanto ao perfil de sensibilidade, elas se mostraram sensíveis aos antifúngicos testados, sendo a resistência ainda um fenômeno raro entre cepas de C. parapsilosis isoladas no Ceará.

INTRODUCTION: C. parapsilosis is the second or third most isolated yeast from blood cultures in various parts of the world. It is a commonly isolated pathogen in Brazil and Ceará. C. parapsilosis is liable to form biofilms on catheters and other medical devices, which contributes to the spread of this yeast. OBJECTIVE: The objective of this study was to identify and assess the antifungal susceptibility of C. parapsilosis isolates from blood and urine samples collected from patients in hospitals in Ceará. METHODS: We isolated and identified 57 strains of C. parapsilosis. The strains were identified by phenotypic and molecular tests. The susceptibility to antifungals was assessed by broth microdilution (Clinical and Laboratory Standards Institute [CLSI] protocol M27A3). We tested five antifungals (amphotericin B, caspofungin, fluconazole, itraconazole and voriconazole). RESULTS AND CONCLUSION: The strains were identified as C. parapsilosis by phenotypic tests and confirmed by molecular tests. As to the sensitivity profile, the strains were sensitive to the antifungal agents, hence resistance is still a rare phenomenon among C. parapsilosis isolates in Ceará.

Anti-Candida albicans effectiveness of citral and investigation of mode of action.

CONTEXT: Candidiasis is a mycosis caused by Candida species, which is of clinical importance due to the increase in resistant yeasts. Candida infection has been a serious health problem due to the inappropriate use of antibiotics. Therefore, it is necessary to study molecules with an antifungal action. Citral is a monoterpene with known pharmacological properties, including antimicrobial action. OBJECTIVE: The aim of this work was to determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of citral and the probable mode of action. MATERIALS AND METHODS: The MIC of citral was determined by the broth microdilution method using Sabouraud dextrose medium. Additionally, the interference of citral in cell wall (sorbitol assay) and the binding of citral to ergosterol and cholesterol were studied, carried out by broth microdilution method. RESULTS: The MIC and MFC of citral were 512 and 1024 µg/mL, respectively. The MIC of amphotericin B was 1 µg/mL. The mechanism of action did not involve either the cell wall or ergosterol. However, the presence of cholesterol increased the MIC of citral to 1024 µg/mL, indicating there is some interaction between citral and cholesterol. Amphotericin B was used as the positive control, and it showed a high MIC in the presence of ergosterol (32 µg/mL), while in the presence of cholesterol MIC increased to 4 µg/mL. CONCLUSION: Citral inhibits the growth of C. albicans. The probable mechanism of action did not involve the cell wall or ergosterol. Citral is able to interact with cholesterol. More studies are necessary to describe their effects completely.

Qualidade microbiológica do leite de búfala e derivados comercializados em Fortaleza, CE / Microbiological quality of buffalo milk and derivatives traded in Fortaleza, CE

A atividade de alguns micro-organismos que contaminam o leite é claramente benéfica para o homem, visto que eles participam ativamente das mudanças físicas, químicas e organolépticas que ocorrem no leite ao se preparar os diversos produtos lácteos por ele consumidos. Os grupos microbianos mais importantes em laticínios podem ser divididos, do ponto de vista funcional, em: bactérias lácticas, bactérias esporuladas, bactperias psicrotróficas, bactérias de origem fecal e microorganismos patogênicos. As Enzimas Betalactamases de Espectro Extendido (ESBL) são enzimas comumente encontradas em cepas de Enterobactérias, principalmente Escherichia coli, Klebsiella penumoniae, Proteus mirabilis. Esses fatos demonstram a importância do trato intestinal humano como um reservatório para cepas produtoras de ESBL. As doenças provocadas por micro-organismos oriundos de alimentos tem se tornado cada vez mais prevalentes. Este estudo teve o objetivo de determinar a presença de ESBL em cepas de Enterobacterias presentes no leite de búfala.

In vitro synergism of simvastatin and fluconazole against Candida species.

Systemic fungal infections are responsible for high mortality rates. Several species of fungi may be involved, but Candida spp. is the most prevalent. Simvastatin is used to lower cholesterol and also exhibits antifungal action. The aim of this study was to evaluate the synergistic action of simvastatin with fluconazole against strains of Candida spp. Susceptibility testing was performed according to protocol M27-A3, by broth microdilution method and the synergistic effect of simvastatin and fluconazole was calculated based on FICI (Fractional Inhibitory Concentration Index). Eleven strains were evaluated, and simvastatin showed a synergistic effect with fluconazole against 10 (91%) of the Candida spp. strains tested. Simvastatin may be a valuable drug in the treatment of systemic infections caused by Candida spp.

In vitro synergism of simvastatin and fluconazole against Candida species / Sinergismo in vitro de sinvastatina e fluconazol contra espécies de Candida

Systemic fungal infections are responsible for high mortality rates. Several species of fungi may be involved, but Candida spp. is the most prevalent. Simvastatin is used to lower cholesterol and also exhibits antifungal action. The aim of this study was to evaluate the synergistic action of simvastatin with fluconazole against strains of Candida spp. Susceptibility testing was performed according to protocol M27-A3, by broth microdilution method and the synergistic effect of simvastatin and fluconazole was calculated based on FICI (Fractional Inhibitory Concentration Index). Eleven strains were evaluated, and simvastatin showed a synergistic effect with fluconazole against 10 (91%) of the Candida spp. strains tested. Simvastatin may be a valuable drug in the treatment of systemic infections caused by Candida spp.

Infecções fúngicas sistêmicas são responsáveis por altas taxas de mortalidade. Várias espécies de fungos podem estar envolvidas, mas Candida spp é a mais prevalente. A sinvastatina é usada para diminuir o colesterol e também exibe ação antifúngica. O objetivo deste estudo foi avaliar a ação sinérgica de sinvastatina e fluconazol contra cepas de Candida spp. O teste de susceptibilidade foi realizado de acordo com o protocolo M27-A3, pelo método de micro diluição em caldo e o efeito sinérgico de sinvastatina e fluconazol foi calculado com base no ICIF (Índice de Concentração Inibitória Fraccionada). Onze cepas foram avaliadas, e a sinvastatina mostrou um efeito sinérgico com o fluconazol em dez (91%) das cepas de Candida spp. Sinvastatina pode ser uma droga valiosa no tratamento de infecções sistêmicas causadas por Candida spp.

Comparação entre microdiluição e disco difusão para o teste de susceptibilidade aos antifúngicos contra Candida spp / Comparison of microdilution broth and disk diffusion for antifungal susceptibility testing against Candida spp

A evolução da resistência fúngica pode ser avaliada pelo teste de susceptibilidade aos antifúngicos. Os protocolos mais utilizados para testes de susceptibilidade são a micro diluição em caldo (MDC), disco difusão (DD) e E-test. O objetivo principal deste estudo foi comparar os testes de sensibilidade realizados pelos métodos de MDC e DD para a anfotericina B e o fluconazol contra cepas de Candida spp. isoladas em Fortaleza/CE. Foram utilizadas 40 C. albicans, 50 C. tropicalis e 47 C. parapsilosis, isoladas de amostras de sangue e urina de pacientes atendidos no Hospital Geral de Fortaleza. Os testes foram realizados pelos métodos MDC e DD, de acordo com os protocolos M27-A3 e M44-A2 do CLSI. As metodologias foram comparadas e calculadas os percentuais de concordância. Para a anfotericina B e fluconazol, ocorreu um predomínio de cepas com susceptibilidade. O percentual de concordância para as metodologias foi acima de 97% e não foram detectados erros graves. A utilização de DD para realização de testes de susceptibilidade antifúngica pode ser aplicada na rotina laboratorial, pois é uma técnica fácil, barata, e de confiança quando comparada ao teste de MDC, sem comprometer os resultados para as cepas de C. albicans, C. tropicalis e C. parapsilosis.

The evolution of fungal resistance can be evaluated by testing susceptibility to antifungal agents. The protocols for susceptibility testing most common are Broth Microdilution (BMD), Disk Diffusion (DD) and E-test. The objective of this study was to compare the susceptibility tests conducted by the BMD and DD methods for amphotericin B and fluconazole against Candida spp. isolated in Fortaleza/CE. Were used 40 C. albicans, 50 C. tropicalis and 47 C. parapsilosis isolated from blood and urine samples of patients treated at Fortaleza General Hospital. The tests were conducted by the BMD and DD methods according to protocols M27-A3 and M44-A2 of the CLSI. These methods were compared and the percentages of agreement were calculated. For amphotericin B and fluconazole was a predominance of strains with reduced susceptibility. The percentage of agreement for the methods tested was above 97%. No serious errors were detected. The use of DD for performing antifungal susceptibility testing can be applied in routine laboratory tests, since one technique is easy, inexpensive, and reliable when compared to the BMD without compromising the results for the strains of C. albicans, C. tropicalis and C. parapsilosis.

Perfil de sensibilidade antimicrobiana de cepas de Escherichia colim, Klebsiella pneumoniae e Enterobacter aerogenes, isoladas de carne de frango / Profile of antimicrobial susceptibility of strains of Escherichia Colim, Klebsiella pneumoniae and Enterobacter aerogenes isolated from chicken meat

Objetivou-se verificar a sensibilidade de cepas de Escherichia coli, Klebsiella pneumoniae e Enterobacter aerogenes isoladas de carne de frango, comercializada na cidade de Fortaleza, CE, frente a vários antimicrobianos e detecção de cepas produtoras de ESBL. As 80 amostras de carne de frango foram submetidas ao teste de susceptibilidade de antimicrobianos (método Kirby-Bauer) e detecção de cepas produtoras de ESBL (CLSI). Constatou-se que a carne de frango apresentou microorganismos multirresistentes a antimicrobianos e produtos de ESBL.

Isolation and antifungal susceptibility testing of Trichosporon asahii in Ceará, Brazil.

Trichosporon spp. are yeasts capable of causing invasive disease, which mainly affect immunocompromised patients. A clinical strain of T. asahii was isolated from the blood cultures of patients admitted to the General Hospital of Fortaleza. Susceptibility tests were conducted by disk diffusion and broth microdilution. The isolated strain of T. asahii was resistant to fluconazole. The patient used amphotericin B and caspofungin in order to facilitate the microbiological cure. It was the first isolation and identification of T. asahii in blood culture in Ceará, Brazil.

Isolation and antifungal susceptibility testing of Trichosporon asahii in Ceará, Brazil / Isolamento e teste de susceptibilidade aos antifúngicos de Trichosporon asahii no Ceará, Brasil

Trichosporon spp. are yeasts capable of causing invasive disease, which mainly affect immunocompromised patients. A clinical strain of T. asahii was isolated from the blood cultures of patients admitted to the General Hospital of Fortaleza. Susceptibility tests were conducted by disk diffusion and broth microdilution. The isolated strain of T. asahii was resistant to fluconazole. The patient used amphotericin B and caspofungin in order to facilitate the microbiological cure. It was the first isolation and identification of T. asahii in blood culture in Ceará, Brazil.

Trichosporon spp. são leveduras capazes de causar doença invasiva, que afetam principalmente pacientes imunocomprometidos. Uma cepa clínica de T. asahii foi isolada em hemocultura de paciente internado no Hospital Geral de Fortaleza. Os testes de suscetibilidade foram realizados por difusão em disco e microdiluição em caldo. A cepa isolada do T. asahii foi resistente ao fluconazol, o paciente fez uso de anfotericina B e caspofungina então a cura microbiológica ocorreu. Foi o primeiro isolamento e identificação de T. asahii em hemocultura no Ceará, Brasil.

Identificação preliminar de algumas espécies do gênero candida spp. em meio cromógeno: resultados de dois anos de um estudo multicêntrico realizado no Ceará / Preliminary identification of some species of the genus candida spp. on chromogenic medium: results of a 2-year multicentre study in Ceará, Brazil

Candidemia é a quarta infecção sanguínea mais importante, sendo Candida albicans a espécie mais comumente isolada. Este estudo teve como objetivos identificar Candida spp. utilizando o meio CHROMagar Candida e comparar com a identificação por microcultivo. Um total de 295 leveduras foram isoladas de sangue e urina de pacientes atendidos no Ceará, coletadas entre 2007 e 2009. As cepas foram semeadas em CHROMagar Candida e as placas foram incubadas a 37grausC por 24 a 72 horas antes da análise. Depois uma colônia foi transferida para o meio ágar arroz tween 80, as placas foram incubadas por 24 a 72 horas a 25grausC e, após o crescimento, examinadas microscopicamente. As espécies identificadas foram C. albicans (129), C. tropicalis (106), C. parapsilosis (20), C. krusei (5) e Candida spp. (35). O CHROMagar Candida mostrou excelente concordância com o microcultivo e pode ser utilizado na identificação presuntiva de Candida spp.