The Oral Microbiology research group conducts studies into the survival strategies of microorganisms, their colonisation and virulence factors, and the interactions that occur between microbes or between microbe and host, especially in the development of microbial communities (biofilms). These studies impinge on many aspects of both oral and systemic health and disease. Key research areas currently include:

Microbial biofilm community development:

Dental plaque biofilms are polymicrobial communities found on oral surfaces embedded within a matrix of host salivary components and microbial extracellular products. Communication between the microorganisms modulates the structure, composition and pathogenic potential of the biofilms. Oral streptococci are especially important because they are primary colonisers of oral cavity surfaces. Their deposition thus provides attachment sites for colonisation by potentially pathogenic organisms such as the fungus Candida albicans, which is the cause of most yeast infections in humans. Our research aims to identify the molecular basis of bacterial and fungal biofilm formation and of polymicrobial community development, in terms of both physical interactions (microbe-microbe or microbe-host), communication/signalling networks, and overall biofilm architecture. These studies have implications for combatting biofilms formed within the oral cavity and at sites throughout the human body.

Antimicrobial resistance and novel biofilm therapeutic strategies:

Antimicrobial resistance (AMR) is one of our most urgent global health threats and is closely linked to biofilm formation. The phenotypic properties that microbes adopt when within a biofilm community often render the microbes recalcitrant to removal by physical or chemical means and can promote the exchange of genetic material that confers enhanced survival capabilities, including AMR. To address this issue, our research aims to determine the mechanistic basis for high levels of AMR associated with biofilm formation. Our studies also aim to develop new strategies to detect and to prevent biofilm-associated infections. As part of this work, we have long-standing collaborations with the Oral Nanoscience and bioMEG groups to develop novel anti-infective biomaterials.

Links between oral microbes and cardiovascular disease:

Oral Streptococcus bacteria are major mediators of a form of cardiovascular disease known as infective endocarditis (IE). This is due to their capacity to activate blood platelets, increasing the risk of thrombotic vegetations forming on heart valves. Ongoing studies aim to reveal new insights into the mechanisms by which oral Streptococcus bacteria interact with platelets and cardiac endothelium to promote unwanted thrombus formation.

Substantial evidence also exists for a causative link between periodontal bacteria and atherosclerosis, a chronic cardiovascular condition associated with hyperinflammation. We are working to determine the mechanisms by which periodontopathogens can trigger this inflammation and so accelerate atherosclerosis.

These project areas are supported by collaborations with academic staff in the Bristol Heart Institute and Clinical Trials Unit. The mechanistic understanding arising from these studies could ultimately lead to the development of novel therapies for IE and atherosclerosis.

Streptococcus colonisation and pathogenesis:

Bacteria within the genus Streptococcus are exquisitely adapted to colonisation of humans and other animals. These bacteria predominantly live in harmony with their hosts, but all have capacity to cause disease should prevailing conditions allow. Streptococci express a myriad of colonisation and virulence attributes that promote their survival at a variety of ecological sites. Many of these factors are surface-expressed adhesins that can promote interactions with a multitude of host substrata or can confer pathogenic capabilities associated with immune evasion or host tissue destruction. Given these critical functions, streptococcal adhesins may represent viable targets for combatting streptococcal disease. In collaboration with academic colleagues in the Bristol BioDesign Institute, we seek to determine the structure-function relationships of these bacterial adhesins with regards to streptococcal colonisation and pathogenesis, and to determine their potential to serve as therapeutic targets to combat infection.