Professor of Molecular Epidemiology
Wellcome Trust Senior Research Fellow, Fellow of Hertford College
My group studies the population biology and evolution of bacterial pathogens, with the objective of translating the insights obtained into benefits for human health. Our work focuses on two globally important pathogens, Neisseria meningitidis and Campylobacter jejuni, although we work on other pathogens through a variety of collaborations. We use a ‘Population Genomics’ approach, which combines data on genome sequence diversity with a variety of types of phenotypic information assembled from large representative bacterial isolate collections. Making extensive use of collaborations within and outside the Department, we explore these data with a range of analysis approaches including: epidemiological studies; dynamic modelling; and phylogenetic and genealogical investigations.
N. meningitidis, the meningococcus, and its close relatives Neisseria gonorrhoeae and Neisseria lactamica, are obligately associated with humans but have different relationships with them (1). N. lactamica very rarely if ever causes disease, N. gonorrhoeae is a global cause of sexually transmitted disease while some, but not all, meningococci are a high-profile cause of septicaemia and meningitis (2). Unravelling genomic differences among these bacteria helps to reveal why such similar bacteria can have such dissimilar clinical effects. We are also interested in the impact of mass vaccination on meningococcal populations (3) and are using the molecular epidemiology of meningococci to develop novel vaccination approaches.
The genus Campylobacter contains two of the most common bacterial enteric pathogens of humans world wide, C. jejuini and Campylobacter coli. These multi-host zoonotic pathogens comprise closely related yet diverse genotypes that exhibit a high degree of host association (4). Transmission studies show that genotypes are transmitted within host populations and that human disease is primarily caused by the genotypes circulating among food animals, especially chickens, rather than other types that may be present on farms (5). There are some data suggesting that agriculture has introduced recent ecological changes affecting the speciation of these bacteria (4). These studies have application in controlling the spread of human campylobacteriosis.
I currently hold an honorary Chair in the Department of Biology, University of Cardiff.
- Bennett JS, Jolley KA, Sparling PF, Saunders NJ, Hart CA, Feavers IM, Maiden MC. Species Status of Neisseria gonorrhoeae: Evolutionary and Epidemiological Inferences from MLST. BMC Biology 2007;5(1):35.
- Buckee CO, Jolley K, Recker M, Penman B, Kriz P, Gupta S, Maiden MC. Role of selection in the emergence of lineages and the evolution of virulence in Neisseria meningitidis. Proceedings of the National Academy of Sciences USA 2008;105:15082-15087.
- Maiden MC, Ibarz-Pavon AB, Urwin R, Gray SJ, Andrews NJ, Clarke SC, Walker AM, Evans MR, Kroll JS, Neal KR, Ala'aldeen DA, Crook DW, Cann K, Harrison S, Cunningham R, Baxter D, Kaczmarski E, Maclennan J, Cameron JC, Stuart JM. Impact of Meningococcal Serogroup C Conjugate Vaccines on Carriage and Herd Immunity. Journal of Infectious Diseases 2008.
- Sheppard SK, McCarthy ND, Falush D, Maiden MC. Convergence of Campylobacter species: implications for bacterial evolution. Science 2008;320(5873):237-9.
- Colles FM, Jones TA, McCarthy ND, Sheppard SK, Cody AJ, Dingle KE, Dawkins MS, Maiden MC. Campylobacter infection of broiler chickens in a free-range environment. Environmental Microbiolgy 2008;10(8):2042-2050.