Molecular factors in the formation and development of fungal biofilms

Abstract

The aim of this review is to highlight the molecular mechanisms of formation and development of fungal biofilms, as well as promising methods of combating them.
Biofilms are a form of coexistence between representatives of one or, less commonly, different species of microorganisms. The term “fungal biofilms” refers to communities that include microscopic representatives of the Fungi kingdom — micromycetes.
The formation of a biofilm entails many advantages for its inhabitants over free-living (planktonic) forms of micromycetes. In the biofilm state, cells acquire greater resistance to physical and chemical stress factors in the environment, such as temperature fluctuations and acid-base balance. In addition, resistance to antifungal drugs (antimycotics) can increase by an order of magnitude, and in some cases by several orders of magnitude. Furthermore, within the biofilm, micromycetes become difficult to reach for the immune defence mechanisms of the host organism, which often leads to the chronicity of the infectious process.
The ability to adhere to various biotic and abiotic substrates allows microorganisms to form biofilms on the surfaces of medical devices and implants (including intravascular and urinary catheters, cardiac valve prostheses and joint endoprostheses) and on the tissues of the host organism, indicating their key role in the development of infections and persistent colonisation.
Quorum sensing, the exchange of signalling molecules using the external environment or biofilm matrix, plays an important role in biofilm formation and in the interaction of microbial cells with each other within biofilms. In recent years, a large number of diverse signalling systems based on the quorum sensing of micromycetes have been discovered, which are involved in a wide range of biological processes, including biofilm formation. Given that most microorganisms are capable of forming biofilms in their natural environment, studying their formation and functioning is one of the priority areas of modern microbiology.