Organisms Involved in Oral Candidosis

Oral candidoses are frequently encountered in the practice of dentistry. Although most oral candidoses are symptomless, they can indicate the presence of an underlying systemic disease, and the persistence of oral candidosis following appropriate conventional management may be one of the first signs of undiagnosed immunosuppression. The opportunistic pathogen Candida albicans is the most commonly isolated species from oral candidal lesions; however, the non-albicans Candida spp. are also implicated in the aetiology of oral candidoses. The effective management of oral candidosis is dependent on an accurate diagnosis, identification and elimination of any predisposing factors (where possible), and the prescription of either topical or systemic antifungal agents. Oral candidosis may have significant implications for the general health of immunosuppressed patients, particularly when caused by the non-albicans spp. and, in cases of severe immunosuppression, systemic candidosis can be life-threatening. This article outlines the clinical presentation and appropriate management for the commonly presenting oral candidal conditions. Dent Update 2001; 28: 132-139 Clinical Relevance: Dental professionals should be aware of the clinical signs of intraoral candidosis, the appropriate special investigations that may be required in order to derive a definitive diagnosis, the significance of immunosuppression in oral candidosis and the appropriate methods of management of the condition. O R A L M E D I C I N E ral candidosis is a collective term for the group of diseases that result from infection with Candida spp., affecting both immunocompetent and immunocompromised individuals. (The terms ‘candidosis’ and ‘candidiasis’ are synonymous: candidosis will be used throughout this article.) Non-candidal oral mycoses (cryptococcosis, histoplasmosis and geotrichosis) are extremely rare and generally diagnosed only in HIV-infected individuals. The effects of oral candidosis may range from localized infections to acute, systemic disseminated disease. Oral candidoses are often symptomless and can be a marker of underlying immunosuppression, and are therefore referred to as the ‘diseases of the diseased’. Immunosuppression is an important consideration for any candidosis that either does not resolve rapidly with appropriate conventional management, or recurs frequently. Oral candidal species can be identified as part of the oral commensal flora in 41% of the ‘normal’ population, and it is impossible to eradicate Candida from the oral cavity completely. Candida spp. are opportunistic pathogens, resulting in disease when the host–commensal relationship is disturbed. Candida albicans is the species most often cultured from candidoses in immunocompetent individuals; however, the non-albicans spp. are more frequently isolated from oral candidoses in the immunocompromised patient, and in such individuals the course of oral candidosis can be protracted and resistant to normal management protocols. Organisms Involved in Oral Candidosis Although C. albicans is frequently identified in the aetiopathogenesis of candidosis, other candidal species can be isolated from oral candidal lesions: ! C. tropicalis; ! C. pseudotropicalis; ! C. glabrata; ! C. krusei; ! C. parapsilosis. PREDISPOSING FACTORS A number of predisposing factors have been identified, all with the common feature of producing a change in the host– commensal balance (altered oral homeostasis), allowing the proliferation of the candidal organisms that results in candidosis. C. albicans normally coexists with Lactobacillus acidophilus in the vegetative (yeast or blastospore) state; however, it can readily change to the elongated cellular form (pseudohyphae) or chlamydospore forms. C. albicans has weak pathogenicity and when an imbalance occurs in the host–commensal relationship this commensal organism has the opportunity to become pathogenic. The production of an endotoxin – an extracellular proteolytic enzyme – is responsible for most of the adverse effects of the intraoral mucous membrane Oral Candidosis