In vitro antifungal susceptibility of clinical isolates of Candida spp. from hospitalized patients

Conventional and alternative antifungal therapies to oral candidiasis

Candida-associated denture stomatitis is the most common form of oral candidal infection, with Candida albicans being the principal etiological agent. Candida adheres directly or via an intermediary layer of plaque-forming bacteria to denture acrylic. Despite antifungal therapy to treat denture stomatitis, infection is reestablished soon after the treatment ceases. In addition, many predisposing factors have been identified as important in the development of oral candidiasis, including malnourishment, common endocrine disorders, such as diabetis mellitus, antibacterial drug therapy, corticosteroids, radiotherapy and other immunocompromised conditions, such as acquired immunodeficiency syndrome (AIDS). These often results in increased tolerance to the most commonly used antifungals. So this review suggests new therapies to oral candidiasis.

In vitro antifungal susceptibility of clinical isolates of Candida spp. obtained from patients with different predisposing factors to candidosis

The increase in the number of infections caused by Candida species and the consequent use of antifungal agents favours an increase of resistant isolates. The aim of this study was to evaluate the antifungal susceptibility of Candida spp. isolates from patients with different systemic predisposing factors to candidosis. Seventy-nine Candida spp. isolates were assayed for in vitro susceptibility to amphotericin B, fluconazole, 5-flucytosine and itraconazole using the technique proposed by the Clinical and Laboratory Standards Institute (CLSI). Four C. albicans, one C. guilliermondii, four C. parapsilosis and two C. tropicalis isolates were resistant to amphotericin B. Only two isolate was resistant to itraconazole. All the isolates tested were susceptible to fluconazole and flucytosine. It could be concluded that the most efficient drugs against the Candida isolates studied were fluconazole and flucytosine and that all of the antifungal agents used in this study were effective against the Candida spp. isolates tested.

Prevalence and antifungal susceptibility of yeasts obtained from the oral cavity of elderly individuals

Infections caused by Candida yeasts are common in elderly individuals. Seventy-five isolates of Candida spp. were obtained from saliva samples of 136 institutionalized elderly individuals resident in six retirement homes of Belo Horizonte, Brazil. Forty-seven isolates (62.66%) were identified as Candida albicans, 15 (20%) as C. tropicalis, 7 (9.33%) as C. glabrata, 4 (5.33) as C. parapsilosis, and 2 (2.67%) as C. guilliermondii. Among the 136 elderly individuals studied, 49 (36%) were male and 87 (64%) were female. Ages ranged from 60 to 90 years old. Sixty-three (46.3%) of the institutionalized individuals were denture wearers and, among them, 53 (84.1%) carried Candida yeasts in the oral cavity. Forty-four subjects presented lesions in the oral mucosa and among these, 36 (82%), had positive culture for Candida spp. The samples were tested for the in vitro susceptibility to amphotericin B, itraconazole, fluconazole and 5-flucytosin, and great variations were observed in the minimum inhibitory concentrations (MIC) of these drugs according to the species.

Predisposing conditions forCandidaspp. carriage in the oral cavity of denture wearers and individuals with natural teeth

Candida species are a normal commensal present in a large percentage of healthy individuals. Denture wearers are predisposed to the development of candidosis and to the presence of Candida spp. The presence of the yeast, even in healthy subjects, should be considered more carefully. We investigated the prevalence of Candida spp. in 112 denture wearers and 103 individuals with natural teeth, patients from the clinic of total prosthesis of the Dental School of the Federal University of Minas Gerais, Brazil, and from the School of Pharmacy and Dentistry of Alfenas, Brazil. Factors like gender, age over 60 years, low education, and xerostomia were directly associated with the presence of Candida yeasts at a significance level of 5% (p > 0.05). However, the major predisposing factor for the carrier state was wearing dentures (p = 0.001). Candida isolates were identified using morphological and biochemical profiles. Seventy-one isolates were identified as C. albicans (65.1%), 15 as C. glabrata (13.7%), 8 as C. parapsilosis (7.3%), 3 as C. krusei (2.7%), and 12 as C. tropicalis (11.0%). Susceptibility testing to fluconazole and itraconazole was also performed with the strains obtained. Both drugs showed a strong inhibition against most oral isolates.Key words: yeast infection, prosthetic devices, oral cavity.

In vitro antimycotic activity of some plant extracts towards yeast and yeast-like strains

As part of screening aimed at the selection of novel antimycotic compounds of vegetable origin, leaf extracts of Camellia sinensis L., Cupressus sempervirens L. and Pistacia lentiscus L. and the seed extract of Glycine soja Sieb. et Zucc. were tested against yeast and yeast-like species implicated in human mycoses. Of the extracts only those of C. sinensis (obtained from a commercial preparation of green tea) exhibited broad activity towards Candida glabrata, Clavispora lusitatiae, Cryptococcus laurentii, Filobasidiella neoformans, Issatchenkia orientalis, Saccharomyces cerevisiae and Prototheca wickerhamii strains. MICs ranging from 300 to 4800 microg extract/mL (corresponding to 130-2010 microg/mL total polyphenols) were observed. Concentrations of the C. sinensis extract over 25 000 microg/mL caused a rapid decrease of viable cells of Fil. neoformans and its activity was dose-dependent. Tests carried out using the pure polyphenols present in C. sinensis extract composition, showed that only epicatechin-3-O-gallate (ECG) and epigallocatechin-3-O-gallate (EGCG) possess antimycotic activity.

Prevalence of Candida spp. in hospitalized patients and their risk factors

A total of 133 Candida spp. strains originating from a group of 100 patients from Santa Casa de Misericórdia of Belo Horizonte, Brazil, between March 1995 and December 1996, were first identified and classified into six different species: Candida albicans (51%), C. tropicalis (33%), C. parapsilosis (8%), C. glabrata (5%), C. krusei (2%) and C. guilliermondii (1%). All C. albicans strains were serotyped and 55% of these were found to belong to serotype A and 45% belonging to serotype B. The medical records of each patient were examined to characterise and survey the main risk factors associated with them. Most of the patients were between 60- and 80-years-old, 53% were males and 47% were females. Most patients were from the intensive care unit (ICU). Only 10 patients were not exposed to antimicrobial agents and 72 patients were not prescribed antifungal agents. Forty patients showed no other clinical condition and all showed some underlying disease that justified hospitalization. Eighty-seven patients had undergone some invasive procedure and 31 patients had been submitted to two different procedures simultaneously.