Research progress on the microbial interaction between <i>Porphyromonas gingivalis</i> and <i>Candida albicans</i> in oral diseases

The human oral microbiota includes over 700 microorganisms such as fungi, bacteria, archaebacteria, and viruses. The interaction between fungi and bacteria, as well as their impact on the host immune system, is currently a popular topic in the field of oral disease research. <i>Porphyromonas gingivalis</i> (<i>P.g</i>) is the key pathogenic bacterium of chronic periodontitis, while <i>Candida albicans</i> (<i>C.a</i>) is a common opportunistic pathogen. <i>P.g</i> and <i>C.a </i>are associated with various oral diseases. A review of the literature suggests that <i>P.g</i> and <i>C.a</i> synergistically increase the amount of biofilm. They adhere to each other, promoting the formation of mixed biofilms. At the same time, <i>C.a</i> can utilize its dense hyphae and metabolic activities to consume oxygen, providing a low-oxygen microenvironment for <i>P.g,</i> thereby enhancing its vitality and virulence. <i>C.a</i> and <i>P.g</i> can also enhance their virulence through heme competition mechanisms and maintain the normal morphology of <i>P.g</i> by extracellular polysaccharides. In addition, <i>P.g</i> and <i>C.a</i> can synergistically invade the host and escape from the host’s immune system, ultimately leading to a state of chronic infection in the host. Based on the interactions of <i>P.g</i> and <i>C.a</i>, numerous studies on prevention and treatment strategies have been conducted, including those of various composite materials and natural plants. However, such drugs are mostly limited to phenotypes and suffer from poor selectivity, thus resulting in a lack of specific drugs and research on their mechanisms. This review aims to explore the latest advances in the bacterial-fungal interactions, highlighting the roles of <i>P.g</i> and <i>C.a</i> in oral diseases, emphasizing the importance of developing treatment strategies for co-infection of <i>P.g</i> and <i>C.a</i>, and providing new ideas for the prevention and treatment of related diseases.