Interactions between Terpinen-4-ol and Nystatin on biofilm of Candida albicans and Candida tropicalis

Abstract The aim of this study was to evaluate the antifungal activity of Terpinen-4-ol associated with nystatin, on single and mixed species biofilms formed by Candida albicans and Candida tropicalis, as well as the effect of terpinen-4-ol on adhesion in oral cells and the enzymatic activity. The minimum inhibitory concentrations and minimum fungicide concentrations of terpinen-4-ol and nystatin on Candida albicans and Candida tropicalis were determined using the microdilution broth method, along with their synergistic activity ("checkerboard" method). Single and mixed species biofilms were prepared using the static microtiter plate model and quantified by colony forming units (CFU/mL). The effect of Terpinen-4-ol in adhesion of Candida albicans and Candida tropicalis in coculture with oral keratinocytes (NOK Si) was evaluated, as well as the enzymatic activity by measuring the size of the precipitation zone, after the growth agar to phospholipase, protease and hemolysin. Terpinen-4-ol (4.53 mg mL-1) and nystatin (0.008 mg mL-1) were able to inhibit biofilms growth, and a synergistic antifungal effect was showed with the drug association, reducing the inhibitory concentration of nystatin up to 8 times in single biofilm of Candida albicans, and 2 times in mixed species biofilm. A small decrease in the adhesion of Candida tropicalis in NOK Si cells was showed after treatment with terpinen-4-ol, and nystatin had a greater effect for both species. For enzymatic activity, the drugs showed no action. The effect potentiated by the combination of terpinen-4-ol and nystatin and the reduction of adhesion provide evidence of its potential as an anti-fungal agent.

Resumo O objetivo desse estudo foi avaliar a atividade antifúngica do Terpinen4-ol associado à nistatina em biofilmes simples e misto, formados por Candida albicans e Candida tropicalis, bem como o efeito do terpinen-4-ol na adesão em células orais e atividade enzimática. As concentrações inibitórias mínimas e as concentrações fungicidas mínimas do terpinen-4-ol e da nistatina em Candida albicans e Candida tropicalis foram determinadas pelo método de microdiluição em caldo, juntamente com a atividade sinérgica (método do tabuleiro de "xadrez"). Biofilmes simples e misto foram preparados usando o modelo de placa de microtitulação estática e quantificados por unidades formadoras de colônias (CFU/mL). O efeito do Terpinen-4-ol na adesão de Candida albicans e Candida tropicalis em co-cultura com queratinócitos orais (NOK Si) foi avaliado, bem como a atividade enzimática, medindo o tamanho da zona de precipitação, após o crescimento em ágar fosfolipase, protease e hemolisina. O terpinen-4-ol (4.53 mg mL-1) e a nistatina (0,008 mg mL-1) conseguiram inibir o crescimento de biofilmes e um efeito antifúngico sinérgico foi demonstrado com a associação de fármaco, reduzindo a concentração inibidora de nistatina até 8 vezes em biofilme simpes de Candida albicans e 2 vezes em biofilme misto. Uma pequena diminuição na adesão de Candida tropicalis em células NOK Si foi mostrada após o tratamento com terpinen-4-ol e a nistatina teve um efeito maior para ambas as espécies. Para a atividade enzimática, as drogas não apresentaram ação. O efeito potencializado pela combinação de terpinen-4-ol e nistatina e a redução de adesão evidenciam seu potencial como agente anti-fúngico.

Antifungal activity of the essential oil of cymbopogon citratus (DC) stapf: an in vitro study

Aim. to evaluate the antifungal potential of the essential oil of cymbopogon citratus by determining the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) for candida albicans (ATCC 90029), candida albicans (CBS 562), candida tropicalis (ATCC 705) and candida tropicalis strains (CBS 94), as well as to analyze the possible mechanism of action of the oil through the addition of sorbitol to the culture medium. methods. for the MIC determination, inocula were previously adjusted through spectrophotometry and 100µL were added to the wells of plates already containing the culture medium and 100µL of the serial dilutions of the oil, incubating them in aerobiosis for 24 hours, with subsequent staining by 1 percent TCT. for the MFC, 50µL of the supernatant from the MIC assay wells were dripped onto petri dishes and incubated in aerobiosis for 24 hours. tests were performed in triplicate and data analysed by descriptive statistics. results. It was determined that the MIC for C. albicans was 125 µg/mL while MIC for C. tropicalis was 250 µg/mL, with the essential oil presenting fungicidal effect for both analyzed yeasts. conclusion. the essential oil of cymbopogon citratus does not act at the cellular wall level and demonstrated an antimicrobial effect on candida albicans and candida tropicalis, therefore acting as a fungicide.

Cellular characterisation of Candida tropicalis presenting fluconazole-related trailing growth

We assessed fluconazole susceptibility in 52 Candida tropicalis clinical strains using seven antifungal susceptibility methods, including broth microdilution (BMD) [standard M27 A3 (with neutral and acid pH), ATB Fungus 3, Vitek 2 system and flow cytometric analysis] and agar-based methods (disk diffusion and E-test). Trailing growth, detection of cell-associated secreted aspartic proteases (Saps) and morphological and ultrastructural traits of these clinical strains were also examined. The ranges of fluconazole 24 h-minimum inhibitory concentration (MIC) values were similar among all methods. The essential agreement among the methods used for MIC determinations was excellent and all methods categorised all strains as susceptible, except for one strain that showed a minor error. The presence of the trailing effect was assessed by six methods. Trailing positivity was observed for 86.5-100 percent of the strains. The exception was the BMD-Ac method where trailing growth was not observed. Morphological and ultrastructural alterations were detected in C. tropicalis trailing cells, including mitochondrial swelling and cell walls with irregular shapes. We tested the production of Saps in 13 C. tropicalis strains expressing trailing growth through flow cytometry. Our results showed that all of the C. tropicalis strains up-regulated surface Sap expression after 24 h or 48 h of exposure to fluconazole, which was not observed in untreated yeast strains. We concluded that C. tropicalis strains expressing trailing growth presented some particular features on both biological and ultrastructural levels.

Antifungal susceptibility testing of Candida tropicalis biofilms against fluconazole using calorimetric indicator resazurin.

Background: C.tropicalis is an important cause of nosocomial infections particularly in immunocompromised patients. Infections caused by Candida spp. are often associated with biofilm formation on implanted medical devices or on epithelial cell surfaces. Phenotypic characteristics of sessile cells in biofilms are known to be different from those of their free-living, planktonic counterparts. Biofilm forming strains often show increased resistance to antimicrobial agents. Materials and Methods : We measured susceptibility to fluconazole of fifty C.tropicalis isolates from immunocompromised (29) and immunocompetent (21) patients by minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC) assays. MBIC was done using the calorimetric indicator resazurin, to measure the metabolically active cells. Results : Biofilm forming cells showed increased resistance to fluconazole. Conclusion : The resazurin dye test was found to be a good method for determining MBIC.

In vitro Evaluation of Antibiotic Lock Technique for the Treatment of Candida albicans, C. glabrata, and C. tropicalis Biofilms

Candidaemia associated with intravascular catheter-associated infections is of great concern due to the resulting high morbidity and mortality. The antibiotic lock technique (ALT) was previously introduced to treat catheter-associated bacterial infections without removal of catheter. So far, the efficacy of ALT against Candida infections has not been rigorously evaluated. We investigated in vitro activity of ALT against Candida biofilms formed by C. albicans, C. glabrata, and C. tropicalis using five antifungal agents (caspofungin, amphotericin B, itraconazole, fluconazole, and voriconazole). The effectiveness of antifungal treatment was assayed by monitoring viable cell counts after exposure to 1 mg/mL solutions of each antibiotic. Fluconazole, itraconazole, and voriconazole eliminated detectable viability in the biofilms of all Candida species within 7, 10, and 14 days, respectively, while caspofungin and amphotericin B did not completely kill fungi in C. albicans and C. glabrata biofilms within 14 days. For C. tropicalis biofilm, caspofungin lock achieved eradication more rapidly than amphotericin B and three azoles. Our study suggests that azoles may be useful ALT agents in the treatment of catheter-related candidemia.

In vitro antifungal sensitivity of fluconazole, clotrimazole and nystatin against vaginal candidiasis in females of childbearing age

Vaginal candidiasis is the most common infection of females. A large variety of antifungal drugs are used for treatment. The objective of this study was isolation and identification of Candida from high vaginal swabs and in vitro antifungal activity of Clotrimazole, Fluconazole and Nystatin against Candida. Two hundred and fifty high vaginal swabs were collected from females reporting at different hospitals of Karachi. Wet mount was performed to observe the budding cells of Candida. Vaginal swabs were cultured on Sabouraud's dextrose agar with added antibiotics. Plates were incubated at room temperature for seven days. Chlamydospores of Candida albicans were identified on corn meal agar. Species of Candida were identified on Biggy agar. In vitro antifungal activity of Clotrimazole, Fluconazole and Nystatin was performed by MIC [Minimum inhibitory concentration], well diffusion method and disc diffusion method. Out of 250 high vaginal swabs, Candida species were isolated in 100 [40%] of cases. Out of 100, C. albican 30 [30%], C. tropicalis 21 [21%], C. parapsillosis 10 [10%], C. parakrusi 8 [8%], C.glabrata 8 [8%], C. krusei 3 [3%] were isolated. In vitro antifungal activity indicated Clotrimazole [MIC 16 and 8 microg/ml] effective against 68 [70%] of Candida SPP, Fluconazole [MIC 64 and 32 microg/ml] effective against 29 [36.2%] and Nystatin disc [100 units] was 51 [63.5%] effective. C. albicans was mainly isolated. Clotrimazole was more effective as compared to Fluconazole and Nystatin. Antifungal susceptibility testing should be determined before therapy to avoid treatment failures

Resistência a antifúngicos de Candida tropicalis isoladas no Estado do Ceará / Antifungal resistance of Candida tropicalis isolated in the State of Ceará

Neste estudo, foi avaliada a resistência a drogas antifúngicas em 51 cepas de Candida tropicalis isoladas de amostras clínicas no Estado do Ceará, Brasil. Resistência antifúngica foi um evento raro no nosso estudo e foi restrita a 3 (5,9 por cento) das cepas de Candida tropicalis, que exibiram resistência a fluconazol e itraconazol.

In this study, the resistance to antifungal drugs was investigated among 51 strains of Candida tropicalis isolated from clinical samples in the State of Ceará, Brazil. Antifungal resistance was a rare finding in our study and was restricted to three (5.9 percent) of the strains of Candida tropicalis. These exhibited resistance to both fluconazole and itraconazole.

Vinegar as an antimicrobialagent for control of Candida spp. in complete denture wearers

The use of denture is known to increase the carriage of Candida in healthy patients, and the proliferation of Candida albicans strains can be associated with denture-induced stomatitis. The aim of this study was to evaluate the use of vinegar as an antimicrobial agent for control of Candida spp. in complete upper denture wearers. Fifty-five patients were submitted to a detailed clinical interview and oral clinical examination, and were instructed to keep their dentures immersed in a 10%vinegar solution (pH less than 3) overnight for 45 days. Before and after the experimental period, saliva samples were collected for detection of Candida, counting of cfu/mL and identification of species by phenotypical tests (germ tube formation, chlamidoconidia production, and carbohydrate fermentation and assimilation). The results were analyzed using Spearman's correlation and Student's t-test (p£0.05). Candida yeasts were present in 87.3% of saliva samples before the treatment. A significant reduction was verified in CFU/mL counts of Candida after treatment. A positive correlation between Candida and denture stomatitis was verified, since the decrease of cfu/mL counts was correlated with a reduction in cases of denture stomatitis. Although it was not able to eliminate C. albicans, the immersion of the complete denture in 10% vinegar solution, during the night, reduced the amounts (cfu/mL) of Candida spp. in the saliva and the presence of denture stomatitis in the studied patients.

Similarity between the in vitro activity and toxicity of two different fungizone™ / lipofundin™ admixtures

OBJETIVO: A anfotericina B é um agente antifúngico de largo espectro bastante empregado na terapia antifúngica. Entretanto, esta molécula apresenta um alto nível de toxicidade que, na maioria das vezes, impede o seu uso contínuo na terapêutica médica. O objetivo deste artigo foi comparar a eficácia e a toxicidade in vitro do Fungizon™ (AmB-D) e de dois sistemas carreadores de AmB. MÉTODOS: Três produtos foram avaliados: o Fungizon™ , e dois sistemas oriundos da mistura entre o Fungizon™ e o Lipofundin™ , uma emulsão de uso parenteral. Tais sistemas foram obtidos por duas técnicas: Na primeira diluiu-se previamanete o Fungizon™ com água para injetáveis e em seguida inseriu-se o Lipofundin™ (AmB-DAL); o segundo método consistiu na diluíção extemporânea do Fungizon™ com a referida emulsão (AmB-DL). Dois modelos celulares foram empregados no estudo: os eritrócitos (RBC) oriundos de doadores humanos e a Candida tropicalis (Ct). A avaliação in vitro (liberação de K+ e hemoglobina, e o índice de sobrevivência celular-CSR) foi realizado com quatro concentrações de AmB (entre 50 e 0.05mg.L-1). RESULTADOS: Os resultados demonstram que a ação da AmB não só foi dependente da concentração como também variou de acordo com o modelo celular e o veículo que diluiu o Fungizon™ . Nas concentrações de 50 mg.L-1, apesar da liberação de hemoglobina ser quase que total para AmB-D (99.51), para a AmB-DAL e AmB-DL este valor tendeu a zero. Um p = 0.000 demonstrou que AmB-D foi significativamente mais hemolítico. CONCLUSÃO: A mistura Fungizon™ -Lipofundin™ aparenta ser um bom sistema para carrear a AmB tendo em vista seu elevado índice terapêutico demonstrado.

Prevalencia de Candida albicans y Candida no albicans en diferentes muestras clínicas: Período 1999-2001 / Prevalence of Candida albicansand Candida no albicans inclinical samples during 1999-2001

Las levaduras implicadas en procesos patológicos son de indiscutible importancia debido al incremento experimentado por estas infecciones en las últimas décadas, a los cambios observados en las especies causales y al uso empírico de antifúngicos. En el Centro de Micología se estudiaron 1006 aislamientos provenientes de una amplia gama de muestras clínicas durante el periodo 1999-2001. Candida albicans con 40,3% resultó la especie de mayor frecuencia de aislamiento, pero las especies de Candida no albicans con 54,9% resultaron de mayor prevalencia y el 4,8% fueron otras levaduras. En los hemocultivos Candida parapsilosis con 34,9%, C. albicans con 30,2% y C. tropicalis con 25,6% resultaron las más recuperadas, mientras que C. glabrata se presentó con un 2,3%. En las secreciones mucosas C.albicans con 60%-80% fue la especie preponderante. Hemos detectado especies de Candida causantes de mediastinitis, lo que nos alerta sobre su importancia en estos procesos. Las infecciones del tracto urinario por levaduras se detectaron en mayor frecuencia en individuos hospitalizados, resultando C. albicans con 47,7% la especie más aislada, y dentro de Candida no albicans, C. glabrata con 24,8% y C. tropicalis con 20,0%. En las onixis candidiásicas C. parapsilosis con 37,7% desplazó a C.albicans con 22,0% de este lugar anatómico. Los estudios de sensiblidad al fluconazol de las especies de Candida nos permiten concluir que C.albicans es una especie sensible y que los mayores porcentajes de resistencia se observaron en C. glabrata (21,41%) y and C. krusei (69,23%).

The importance of epidemiological monitoring of yeasts involved in pathologic processes is unquestionable due to the increase of these infections over the last decade, the changes observed in species causing candidiasis, and empirical antifungal treatment. At the Mycology Center, 1006 isolates from a wide range of clinical samples were studied during 1999-2001. Candida albicans (40.3%) was the most isolated species, although, the Candida no albicans species with 54.9% showed the major prevalence. In blood cultures Candida parapsilosis (34.9%), C. albicans (30.2%) and C. tropicalis (25.6%) were recovered most frequently while C. glabrata represented only 2.3%. C. albicans with 60%-80% was the predominant specie in mucosal surface. We also detected Candida mediastinistis, which alert us over the importance at this location. Urinary tract infections caused by yeasts were more frequent in hospitalized patients, being C. albicans (47.7%), the most commonly isolated, followed by C. glabrata (24.8%) and C. tropicalis (20.0%). In the candidal onychomycoses, C. parapsilosis (37.7%) outplaced C. albicans (22.0%). Fluconazole susceptibility studies of Candida species allowed us to conclude that the majority of C. albicans islolates are susceptible, and that the highest resistance averages were observed in C. glabrata (21.41%) and C. krusei (69.23%).

Tratamiento con caspofungina de endocarditis por Candida tropicalis resistente a fluconazol / Treatment with caspofungin of Candida tropicalis endocarditis resistant to fluconazol

Fungal endocarditis, in particular due to Candida species, requires medical and surgical treatment and amphotericin B is the drug of choice. Caspofungin is an echinocandin very effective against Candida and Aspergillus. We present a patient with Candida tropicalis endocarditis, fluconazol resistant, treated with caspofungin, on a compassional basis as a result of adverse effects with amphotericin B. The patient had a microbiological response.

Las endocarditis causadas por hongos, (Candida en particular), requieren tratamiento médico-quirúrgico,siendo la anfotericina B la droga de elección. Caspofungina es una equinocandina con gran actividadsobre Candida y Aspergillus. Se presenta un paciente con una endocarditis por Candida tropicalis resistente a fluconazol tratado con caspofungina bajo un esquema de salvataje, luego de haber presentado efectos adversos por anfotericina B. El paciente tuvo respuesta microbiológica.