Oral Microbiology

Oral Microbiology is co-located with the Centre for Infectious Disease in the Institute of Cell & Molecular Science.

Undergraduate teaching on the BDS curriculum includes contributions to the Human Health & Disease, Plaque Related Diseases and Oral Cavity modules.

Postgraduate teaching includes contributions to the Experimental Pathology and Clinical Microbiology MSc courses, and a module covering the microbiology of the oral cavity on the new Oral Biology MSc course.

Research

Co-location with the Centre for Infectious Disease in the Institute of Cell & Molecular Science enhances the training and research environment through increased critical mass of research workers and facilities.

Research programmes include molecular mechanisms in pathogenesis and the role of oral bacteria in extra-oral infections. Specific research areas include:

Streptococcal diversity and pathogenesis
This research focuses on oral streptococcal diversity and the role of these bacteria in oral and systemic disease using molecular and biochemical approaches. Studies have included the description of previously undescribed bacterial taxa (species and subspecies) and variations in strain phenotype relating to potential virulence.

Collaborative studies with workers in Tokushima University, Japan have led to the discovery of a human-specific cytolysin expressed by the oral commensal Streptococcus intermedius, an organism shown to be associated with deep-seated abscesses notably of the central nervous system. Investigation into the effects of the cytotoxin on a range of potential target cell types, at lethal and sub-lethal concentrations are being undertaken.

Oral bacteria and systemic disease
Studies based upon the 16S rRNA gene have supported the role of Fusobacterium nucleatum in adverse pregnancy outcomes. Intergenic ribosomal gene spacer sequence analysis is being used to investigate the origin of bacteria identified from the uterine environment.

Control of the oral flora
These studies include the role of innate mechanisms to control the oral flora, in relation to the antimicrobial effects of nitric oxide, and to determine the role of adrenomedullin and other host defence peptides.

Development of novel antimicrobials
The group has a long standing expertise in the development of novel antimicrobial agents. The use of nanocomposite hydroxyapatite-based implant coatings to prevent peri-implantitis is being explored. These research charity and industry funded studies to develop improved bone integration and antimicrobial characteristics complement work by the materials group (Hill) on the use of bioactive glasses for oral applications.

Close links are held with the MRC Microbial Pathogenesis Group under the directorship of Professor M. Curtis. Research interests of the Group include:

Proteases in microbial virulence
This MRC funded research focuses upon the structure and genetics of the proteolytic enzymes of the periodontal pathogen Porphyromonas gingivalis. Bacterial protease inhibitors as specific antimicrobials are being studied in collaboration with the commercial biotechnology sector aiming towards inhibitor design for a number of important pathogens including Pseudomonas aeruginosa.

Bacterial glycoproteins
We have recently discovered that the proteases of P. gingivalis are variably glycosylated. The research is to characterise the synthetic pathway by which this is achieved, and to determine the role of these modifications in host-parasite interractions.

Horizontal gene transfer and pathogenicity islands
The studies are to determine the origin and molecular epidemiology of a genetic locus that has arisen in P gingivalis by horizontal gene transfer. The locus encodes a major surface antigen and has been shown to be important in pathogenesis.