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Research Fellows Directory

Stephen Diggle

Dr Stephen Diggle

Research Fellow


University of Nottingham

Research summary

At the heart of tackling the huge challenge posed by infectious microorganisms is the overwhelming need to understand their nature. A major question is why do some species of bacteria rapidly kill their host whilst others are relatively benign? For example, Yersinia pestis, the causative organism of plague, is a highly virulent human pathogen whilst the closely related Yersinia pseudotuberculosis causes a much less severe disease. Using molecular techniques such as mutating certain genes, microbiologists have made significant advances over recent decades in working out the mechanisms that govern the production of virulence factors involved in causing disease in many bacterial species. Despite this, there are also evolutionary and ecological factors which will influence virulence. Many of these ideas have arisen through the development of evolutionary theory and yet there is strikingly little empirical evidence testing them. By applying both mechanistic and adaptive approaches to microbial behaviours we can begin to address questions such as what factors influence cooperation and the evolution of virulence in microbes and furthermore, we can exploit this to develop new antimicrobial strategies which is important considering antibiotic resistance and the lack of new antibiotics in the pipeline. For instance, bacterial cells cooperate with each other using a signalling system known as quorum sensing to regulate toxin production and cause disease. To date I have shown that quorum sensing between microbial cells can be disrupted by asocial cheats who no longer cooperate. During infection studies, I demonstrated that cheats can invade infections made up of cooperating cells and that these cheats resulted in a significant reduction in disease. This suggests a novel treatment strategy whereby antisocial bacteria can be used against a cooperating population to disrupt their overall ability to cause disease.

Interests and expertise (Subject groups)

Grants awarded

Bacterial cooperation and virulence: an evolutionary approach

Scheme: University Research Fellowship

Dates: Oct 2011 - Sep 2014

Value: £300,195.94

The Evolution of Cooperation and Conflict in Social Bacteria

Scheme: University Research Fellowship

Dates: Oct 2006 - Sep 2011

Value: £433,923.20