The Patrick Group

The Patrick group are studying the virulence and phylogeny of bacteria in the context of opportunistic infection arising from anaerobic bacteria of the normal resident microbiota and their relationship with health and disease; informing translational research.  This work has 3 strands:

Bacteroides fragilis

Professor Patrick has over 30 years’ experience of studying the obligately anaerobic bacterium Bacteroides fragilisB. fragilis is a member of the normal resident human intestinal microbiota and an important opportunistic pathogen capable of causing considerable morbidity and mortality. She was Principal Investigator on the first B. fragilis whole genome sequencing project. This generated exciting data in relation to our understanding of the mechanisms that generate the heterogeneity of surface component expression, which she first reported in the 1980s.  These mechanisms involve DNA recombination events at an extensive number of loci in a variety and number that had not been observed in other bacteria. Whole genome sequence comparisons also revealed an unprecedented diversity of polysaccharide biosynthesis associated loci amongst strains. In addition, a unique homologue of eukaryotic ubiquitin was discovered in B. fragilis which is thought to have been acquired by horizontal gene transfer.  These findings could have profound implications for our understanding of a wide range of human disease, including inflammatory bowel diseases.

Currently, selected genes and gene products are being studied in relation to their potential involvement in virulence, host colonisation and human disease, including inflammatory bowel disease,  in parallel with whole genome sequence comparative analyses of a further 5 B. fragilis genomes.

Propionibacterium acnes

Recent studies, led by Dr Andrew McDowell (Senior Research Fellow in the Patrick group) have provided evidence that the skin bacterium Propionibacterium acnes, in addition to a recognised role in prosthetic joint infection and involvement in inflammatory acne, infects the human prostate gland where it is associated with acute and chronic inflammatory changes that could potentially lead to cancer development. This discovery may represent a breakthrough in our understanding of the complex origins of this common cancer and highlight new treatments. Key to our understanding of the role of P. acnes in cancer and other diseases is an ability to discriminate between the diverse phylogenetic groups of P. acnes; Dr McDowell has developed a robust molecular typing scheme (, which in parallel with multiple complete genome sequence analyses, will enable definitive disease association study of the different P. acnes phylogenetic groups.

Translational research

Skin bacteria as a source of surgical infections: molecular epidemiology and prevention of wound contamination

A study, carried out in by the Patrick Group showed that nearly 30% of operative wounds relating to back surgery contain bacteria of the normal skin microbiota, despite pre-operative treatment of the patient’s skin with antiseptic.  The Patrick group is currently conducting a blind randomised controlled trial to determine if a change to the current procedures for skin antisepsis prior to surgery improves surgical wound contamination. In addition, molecular epidemiological analyses of skin and surgical wound isolates is being carried out.  This study will enable us to determine if it will be possible to counter the potential rise in post-operative infection arising from antibiotic resistant bacteria by changing skin antisepsis.