Recent mouse and rat methods for the study of experimental oral candidiasis

The Candida genus expresses virulence factors that, when combined with immunosuppression and other risk factors, can cause different manifestations of oral candidiasis. The treatment of mucosal infections caused by Candida and the elucidation of the disease process have proven challenging. Therefore, the study of experimentally induced oral candidiasis in rats and mice is useful to clarify the etiopathology of this condition, improve diagnosis, and search for new therapeutic options because the disease process in these animals is similar to that of human candidiasis lesions. Here, we describe and discuss new studies involving rat and mouse models of oral candidiasis with respect to methods for inducing experimental infection, methods for evaluating the development of experimental candidiasis, and new treatment strategies for oral candidiasis. © 2013 Landes Bioscience.

Invasive candidiasis and oral manifestations in premature newborns

Objective: To investigate prevalence of invasive candidiasis in a Neonatal Intensive Care Unit and to evaluate oral diseases and Candida spp. colonization in low birth weight preterm newborns. Methods: A descriptive epidemiological study performed in two stages. First, prevalence of candidiasis was analyzed in a database of 295 preterm patients admitted to hospital for over 10 days and birth weight less than 2,000g. In the second stage, oral changes and Candida spp. colonization were assessed in 65 patients weighing less than 2,000g, up to 4 week-old, hospitalized for over 10 days and presenting oral abnormalities compatible with fungal lesions. Swab samples were collected in the mouth to identify fungi. Results: Prevalence of candidiasis was 5.4% in the database analyzed. It correlated with prolonged hospital length of stay (p<0.001), in average, 31 days, and 85% risk of developing infection in the first 25 days. It correlated with low birth weight (p<0.001), with mean of 1,140g. The most frequent alterations were white soft plaques, detachable, in oral mucosa and tongue. Intense oral colonization by Candida spp was observed (80%). Conclusions: The frequency of invasive candidiasis was low and correlated with low birth weight and prolonged hospital stay. The most common oral changes were white plaques compatible with pseudomembranous candidiasis and colonization by Candida spp. was above average.

Evaluation of Staining Methods for Cytologic Diagnosis of Oral Lesions

ObjectiveTo compare the efficacy of Papanicolaou, hematoxylin-eosin (H-E), Leishman and periodic acid-Schiff (PAS) staining for Cytologic diagnosis of oral lesions.Study DesignPatients from the Discipline of Stomatology, Sao Jose dos Campos Dental School, from the wards of Hospital Heliopolis and from the dentistry outpatient clinic of the University Hospital, University of São Paulo Medical School, with the following diseases, were selected: erythematous candidiasis (n = 9), pseudomembranous candidiasis (n = 10), squamous cell carcinoma In = 19), herpes simplex (n = 8), paracoccidioidomycosis In = 8) and pemphigus vulgaris (n = 1).ResultsThe different staining methods were compared regarding the quality of definition of cytoplasmic and nuclear morphologic characteristics and the identification of bacteria, fungi, inflammatory cells and secretions. Papanicolaou and H-E staining were considered better methods. In cases of fungal infections, PAS staining is useful and should be applied as a complementary method.ConclusionWithin the limitations of this study, it can be concluded that the cytologic diagnosis of oral lesions along with different staining methods is a useful tool for oral diagnosis. (Acta Cytol 2008;52:697-701)

Oral manifestations during chemotherapy for acute lymphoblastic leukemia: A case report

A 14-year-old, male patient was referred for the treatment of mucositis, idiopathic facial asymmetry, and candidiasis. The patient had been undergoing chemotherapy for 5 years for acute lymphoblastic leukemia. He presented with a swollen face, fever, and generalized symptomatology in the mouth with burning. On physical examination, general signs of poor health, paleness, malnutrition, and jaundice were observed. The extraoral clinical examination showed edema on the right side of the face and cutaneous erythema. On intraoral clinical examination, generalized ulcers with extensive necrosis on the hard palate mucosa were observed, extending to the posterior region. Both free and attached gingivae were ulcerated and edematous with exudation and spontaneous bleeding, mainly in the superior and inferior anterior teeth region. The tongue had no papillae and was coated, due to poor oral hygiene. The patient also presented with carious white lesions and enamel hypoplasia, mouth opening limitation, and foul odor. After exfoliative cytology of the affected areas, the diagnosis was mixed infection by Candida albicans and bacteria. Recommended treatment was antibiotics and antifungal administration, periodontal prophylaxis, topical application of fluor 1.23%, and orientation on and control of proper oral hygiene and diet during the remission phase of the disease.

Experimental candidosis and recovery of Candida albicans from the oral cavity of ovariectomized rats

The aim of this study was to analyze the development of candidosis and the recovery of C. albicans from the oral cavity of ovariectomized and sham-ovariectomized rats. One hundred aiid twenty-four rats originally negative for Candida spp. in the oral cavity were divided into two groups: ovariectomized and sham-ovariectomized. Fifty-eight ovariectomized and the same quantity of sham-ovariectomized rats were inoculated with C. albicans for the study of candidosis development and recovery of yeast. Four animals from each group were not inoculated with yeast suspension and were submitted to tongue dorsum morphologic analysis by optical and scanning electron microscopy. The development of candidosis in the tongue dorsum was observed by optical and scanning electron microscopy in the periods of 6 hr, 24 hr, 7 days and 15 days after the last inoculation. Recovery of C. albicans was performed by oral samples plating on Sabouraud agar after 1,2, 5 and 7 days and progressively at each 15-day interval until negative cultures for yeasts were obtained. The results were analyzed by Mann-Whitney and Student's t tests. The tongue dorsum of sham-ovariectomized and ovariectomized rats, not infected by Candida, presented normal aspect. Among the infected rats, the ovariectomized group showed less occurrence of candidosis lesions and lower recovery of C. albicans from the oral cavity in relation to the sham-ovariectomized group. It could be concluded that candidosis was less frequent from the oral cavities of ovariectomized rats in relation to sham-ovariectomized.

Aislamiento e identificación de Candida albicans de la cavidad oral, mediante el uso del Agar cromogénico en la población interna del Asilo San Antonio y Casa de la Misericordia de la ciudad de San Miguel

La investigación se realizó en la población con los adultos mayores del Asilo San Antonio y Casa de la Misericordia de la Ciudad de San Miguel, en el período de Junio a Julio de 2015. El Objetivo de la investigación fue aislar e identificar Candida albicans en muestras de la cavidad oral, mediante el uso del agar cromogénico de la población interna del Asilo San Antonio y Casa de la Misericordia de la Ciudad de San Miguel. El diseño metodológico es de tipo descriptivo, prospectivo, transversal, y de laboratorio, para el cual se tomaron 61 muestras de la cavidad oral de los internos en el Asilo San Antonio y Casa de la Misericordia de la Ciudad de San Miguel a través de un hisopado bucal con el que se realizó un examen directo al fresco con Solución Salina estéril al 0.85% en la búsqueda de levaduras; posteriormente se procedió a sembrar en el agar cromogénico Brilliance Candida, para observar el crecimiento de colonias verdes, las cuales indican la presencia de Candida albicans, como agente causal de Candidiasis oral. Resultados: De las 61 muestras procesadas a 26 se les aisló e identificó Candida albicas con un porcentaje de 42.7%. De los 22 adultos mayores que presentaban lesiones sugestivas a candidiasis oral a 20 se les aisló e identificó Candida albicans de los cuales 15 (88.2%) pertenecen al Asilo San Antonio y 5 (100%) pertenecen a la Casa de la Misericordia. De los 10 adultos mayores que reportaron que no practican el aseo bucal se les aisló e identificó Candida albicans a 3 (33.3%) de ellos que se encuentran en el Asilo San Antonio. A 5 internos que reportaron practicar algunas veces el aseo bucal también se les aisló e identificó Candida albicans, 4 (44.4%) pertenecen al Asilo San Antonio y 1 (50%) a la Casa de la Misericordia. De los 18 adultos mayores que usan prótesis dentales a 7 (53.8%) se les aisló e identificó Candida albicans en el Asilo San Antonio y en la Casa de la Misericordia a 5 (100%) internos se les aisló e identificó Candida albicans. De 35 adultos mayores que reportaron que usan antibiótico a 14 (46.7%) que se encuentran en el Asilo San Antonio se les aisló e identificó Candida albicans. Con respecto Casa de la Misericordia de los 5 (100%) que reportaron que usan antibiótico no se les aisló Candida albicans. En 16 (26.2%) muestras no se observó crecimiento de ninguna especie de Candida. Conclusiones: Se estudió a la población interna del Asilo San Antonio y Casa de La Misericordia debido a que los adultos mayores son vulnerables a las infecciones por hongos oportunistas ya que su sistema inmunológico se encuentra disminuido unido a una serie de factores predisponentes, como el uso de prótesis dentales, antibióticos, mal higiene bucal y diabetes. Mediante el uso del agar Brilliance Candida se logró diferenciar otras especies del género Candida como Candida tropicalis 26.2%, Candida krusei 3.3% y Candida glabrata 1.6%. De acuerdo a estos resultados y las conclusiones de la investigación se plantean algunas recomendaciones orientadas principalmente al personal de salud para brindar apoyo a este tipo de estudios.

Caracterización de aislamientos atípicos de Candida dubliniensis

241 p. : il., gráf

Molecular fingerprinting methods for the discrimination between C-albicans and C-dubliniensis

Opportunistic fungal pathogens are becoming increasingly important causes of both community-acquired and nosocomial infections. The most important fungal pathogens are yeast species belonging to the genus Candida. These species show differences in levels of resistance to antifungal agents and mortality. Consequently, it is important to correctly identify the causative organism to the species level. Identification of Candida dubliniensis in particular remains problematic because of the high degree of phenotypic similarity between this species and Candida albicans. However, as the differences between both are most pronounced at the genetic level, several studies have been conducted in order to provide a specific and rapid identification fingerprinting molecular test. In most candidal infectious, no single DNA fingerprinting technique has evolved as a dominant method, and each method has its advantages, disadvantages and limitations. Moreover, the current challenge of these techniques is to compile standardized patterns in a database for interlaboratory use and future reference. This review provides an overview of most common molecular fingerprinting techniques currently available for discrimination of C. albicans and C. dubliniensis.

Phenotypic methods and commercial systems for the discrimination between C-albicans and C-dubliniensis

Candida dubliniensis is a recently described Candida species associated with oral candidosis that exhibits a high degree of phenotypic similarity to Candida albicans. However, these species show differences in levels of resistance to antimycotic agents and ability to cause infections. Therefore, accurate clinical identification of C. dubliniensis and C. albicans species is important in order to treat oral candidal infections. Phenotypic identification methods are easy-to-use procedures for routine discrimination of oral isolates in the clinical microbiology laboratory. However, C. dubliniensis may be so far underreported in clinical samples because most currently used identification methods fail to recognize this yeast. Phenotypic methods depend on growth temperature, carbon source assimilation, chlamydospore and hyphal growth production, positive or negative growth on special media and intracellular enzyme production, among others. In this review, some phenotypic methods are presented with a special emphasis on the discrimination of C. dubliniensis and C. albicans.

Emprego da imunofluorescência direta no estudo das alterações de mucosa de palato, compatíveis com candidíase atrófica crônica, em indivíduos portadores de próteses dentárias totais muco-suportadas.

Histopathology by hematoxilin-eosin (HE) and periodic acid Schiff (PAS), concomitant direct immunofluorescence (DI) against total human immunoglobulins and against Candida albicans, was effectuated in 25 persons dentures wearers. In 5 persons without chronic athrofic candidiasis (CAC) clinical signals in the palate the HE showed wise inflammatory elements in the connective tissue and the PAS marked the continuous basal layer, the intra-cellular grains of granular layer and the uniform parakeratin on epithelial surface. In 20 others, with palatal signals of CAC, in the HE was frequent the features encountered in Candida infected and PAS revealed, beside descontinuous lamina basal and epithelial surface covered by tide and discontinuous parakeratin, the presence of round bodies few largers that presents in the granular layer, casually isolated in the medial portion of ret pegs and connective papillae. In the first 5 persons the DI against total human immunoglobulins not showed signals of the humoral immunologic phenomena, the same was valid to others 20 patients with CAC clinical aspects. However the DI with conjugate against C. albicans in the 20 cases with CAC signals revealed suitable aspects of the structures assumed by Candida in tissues. Cultures of samples obtained of the persons with CAC signals was positive in 100% to Candida, 70% presumptively albicans, against 80% of positiviness to generus Candida, 67% presumptively albicans, in the persons without CAC signals.

Hyaluronidase and chondroitin sulphatase production by different species of Candida

The production of hyaluronidase and chondroitin sulphatase by Candida albicans, Candida tropicalis, Candida parapsilosis, Candida guilliermondii and Candida krusei was investigated using a complex culture medium (Sabouraud glucose agar) and a chemically defined medium. Among the 63 C. albicans isolates tested, 61 (97.8%) were found to be hyaluronidase and chondroitin sulphatase producers; one isolate produced only chondroitin sulphatase and one other was unable to produce either enzyme. The second major hyaluronidase and chondroitin sulphatase producing species was C. tropicalis followed by C. guilliermondii, C. parapsilosis and C. krusei. Among the C. albicans isolates tested no relation between the source of isolation and the amount of hyaluronidase and chondroitin sulphatase produced was found.

In vitro activity of zinc oxide-eugenol and glass ionomer cements on Candida albicans

The aim of this study was to evaluate in vitro the antimicrobial activity of glass ionomer (GIC) and zinc oxide-eugenol (ZOE) cements against Candida albicans. Standardized GIC and ZOE specimens were maintained in contact with C. albicans suspension (1 x 10(6) cells/ml) at 37 degrees C for 24 h, 48 h or 7 days. A control group without any testing cement was included. After the incubation period, aliquots of 0.1 ml were plated on Sabouraud's agar, and then the number of colonies was counted. The results were expressed as values of logarithms of colony-forming units per milliliter (log CFU/mL) and were analyzed statistically by Kruskal-Wallis ANOVA. After 48 h of incubation, the ZOE group presented no growth of C. albicans. GIC and control groups presented similar mean values at all tested periods. According to the results obtained, it could be concluded that, under the experimental conditions, ZOE cement was more effective in vitro against C. albicans than GIC.

Effect of the association of nystatin with a tissue conditioner on its ultimate tensile strength

Purpose: This study evaluated the ultimate tensile strength of a tissue conditioner without nystatin incorporation (GI - control group) and the same tissue conditioner modified by the addition of nystatin in two concentrations: GII - 500,000 International Units (U) and GIII - 1,000,000 U, in which each milligram of the medicament corresponded to 6079 U. Materials and Methods: Dumbbell-shaped specimens (N = 7) with a central cross-sectional area of 33 × 6 × 3 mm were produced for the three experimental groups. After polymerization following manufacturer's instructions, specimens were immersed in distilled water at 37°C for either 24 hours or 7 days and then tested in tension in the MTS 810 at 40 mm/minute. Data were analyzed by two-way ANOVA followed by Tukey's test, at 95% level of confidence. Results: The means (force-grams (gf) ± standard deviation) of the ultimate tensile strength were: GI - 634.29 ± 122.80; GII - 561.92 ± 133.56; and GIII - 547.30 ± 73.47 for 24-hour storage, and GI - 536.68 ± 54.71; GII - 467.50 ± 143.51; and GIII - 500.62 ± 159.76 for 7-day storage. There were no statistically significant differences among the three experimental groups (p > 0.05). The ultimate tensile strength means of all experimental groups after 7 days were significantly lower than those observed after 24 hours (p = 0.04). Conclusions: The results of this study suggest that the addition of nystatin into the tissue conditioner investigated in concentrations below 1,000,000 U did not affect its ultimate tensile strength. Copyright © 2006 by The American College of Prosthodontists.

Identification of Candida species in the clinical laboratory: A review of conventional, commercial, and molecular techniques

In healthy individuals, Candida species are considered commensal yeasts of the oral cavity. However, these microorganisms can also act as opportunist pathogens, particularly the so-called non-albicans Candida species that are increasingly recognized as important agents of human infection. Several surveys have documented increased rates of C. glabrata, C. tropicalis, C. guilliermondii, C. dubliniensis, C. parapsilosis, and C. krusei in local and systemic fungal infections. Some of these species are resistant to antifungal agents. Consequently, rapid and correct identification of species can play an important role in the management of candidiasis. Conventional methods for identification of Candida species are based on morphological and physiological attributes. However, accurate identification of all isolates from clinical samples is often complex and time-consuming. Hence, several manual and automated rapid commercial systems for identifying these organisms have been developed, some of which may have significant sensitivity issues. To overcome these limitations, newer molecular typing techniques have been developed that allow accurate and rapid identification of Candida species. This study reviewed the current state of identification methods for yeasts, particularly Candida species. © 2013 John Wiley & Sons A/S.