Cross-kingdom interaction between Candida albicans and oral bacteria

Abstract

Candida albicans is a symbiotic fungus that commonly colonizes on oral mucosal surfaces and mainly affects immuno-compromised individuals. Polymicrobial interactions between C. albicans and oral microbes influence the cellular and biochemical composition of the biofilm, contributing to change clinically relevant outcomes of biofilm-related oral diseases, such as pathogenesis, virulence, and drug-resistance. Notably, the symbiotic relationships between C. albicans and oral bacteria have been well-documented in dental caries, oral mucositis, endodontic and periodontal diseases, implant-related infections, and oral cancer. C. albicans interacts with co-existing oral bacteria through physical attachment, extracellular signals, and metabolic cross-feeding. This review discusses the bacterial-fungal interactions between C. albicans and different oral bacteria, with a particular focus on the underlying mechanism and its relevance to the development and clinical management of oral diseases.

Keywords: Candida albicans; bacteria; biofilm; co-infection; oral diseases.

FIGURE 1

C. albicans can interact with a variety of oral microbes, and these cross-kingdom interactions have been demonstrated involved in the pathogenesis of oral diseases for years, including dental caries, oral candidosis, endodontic disease, periodontitis, and other biofilm-related oral diseases. C. albicans can interact with oral bacteria via physical attachment through fungal cell walls (e.g., surface proteins and EPS), extracellular signals, metabolite cross-feeding, and environment changing.

FIGURE 2

The typical physical attachment mechanisms underlying the interaction between C. albicans and streptococci. C. albicans physically interacts with MGS through proteins/receptors on cell wall surface of both fungi and bacteria whereas EPS is critical to the mutualistic interaction between C. albicans and S. mutans instead of cell-cell physical adhesion.