Experimental Oral Candidiasis in Animal Models

Abstract

Oral candidiasis is as much the final outcome of the vulnerability of the host as of the virulence of the invading organism. We review here the extensive literature on animal experiments mainly appertaining to the host predisposing factors that initiate and perpetuate these infections. The monkey, rat, and mouse are the choice models for investigating oral candidiasis, but comparisons between the same or different models appear difficult, because of variables such as the study design, the number of animals used, their diet, the differences in Candida strains, and the duration of the studies. These variables notwithstanding, the following could be concluded. (i) The primate model is ideal for investigating Candida-associated denture stomatitis since both erythematous and pseudomembranous lesions have been produced in monkeys with prosthetic plates; they are, however, expensive and difficult to obtain and maintain. (ii) The rat model (both Sprague-Dawley and Wistar) is well proven for observing chronic oral candidal colonization and infection, due to the ease of breeding and handling and their ready availability. (iii) Mice are similar, but in addition there are well characterized variants simulating immunologic and genetic abnormalities (e.g., athymic, euthymic, murine-acquired immune deficiency syndrome, and severe combined immunodeficient models) and hence are used for short-term studies relating the host immune response and oral candidiasis. Nonetheless, an ideal, relatively inexpensive model representative of the human oral environment in ecological and microbiological terms is yet to be described. Until such a model is developed, researchers should pay attention to standardization of the experimental protocols described here to obtain broadly comparable and meaningful data

Fluconazole impacts the extracellular matrix of fluconazole-susceptible and -resistant Candida albicans and Candida glabrata biofilms

“…Candida species are commensal fungi of the oral cavity of healthy individuals that can become opportunistic pathogens in some situations, for example, when there are changes in the immune system, metabolic dysfunction, or in the elderly population [1–7]. Moreover, increased use of broad-spectrum antibiotics, cytotoxic chemotherapies, and transplantation also enhances the risk for infection by these opportunistic fungi [7].…”

“…These infections are known as candidiasis. Candida albicans is the main species associated with candidiasis, while Candida glabrata is one of the most predominant non- albicans species that has been linked to the development of oral infections [1–6]. It is an opportunistic pathogen in immunocompromised individuals [7,8], and it has an innate resistance to azoles [9,10].…”

Susceptibility of Candida albicans to photodynamic therapy in a murine model of oral candidosis

“…1,2 The predisposing factors of oral candidosis include immunocompromised states, diabetes mellitus, dental prostheses, xerostomia, 3,4 and prolonged use of antibiotics or immunosuppressive drugs. 5,6 With the advent of the human immunodeficiency virus (HIV) infection, increased attention has been paid to oral candidosis, because up to 90% of HIV-infected individuals suffer from oral Candida infection. 3 The widespread use of topical and systemic antifungal agents as conventional treatment for oral candidosis has resulted in the development of resistance in C. albicans.…”

Atopic Dermatitis and Fungi

“…An prevalence of 3 to 65% in asymptomatic persons has been reported (111). Under the influence of various predisposing factors, the prevalence may increase (111,129). The most commonly cultured Candida species is C. albicans, but C. glabrata, C. tropicalis, C. parapsilosis, and C. krusei may also be found.…”

“…Isolation of Candida from the gastrointestinal tract or, in women, the vagina does not automatically imply disease because many healthy persons are colonized with Candida in these areas (85,111,129). An prevalence of 3 to 65% in asymptomatic persons has been reported (111).…”