The rise in antimicrobial resistance is at at the point of crisis, and novel antimicrobial strategies are required. We are searching for novel antimicrobial targets to combat this. The co-ordinated communities that bacteria form on surfaces (biofilms) are especially resistant to antimicrobials, so we are interrogating these at a single cell level in real time to investigate the metabolic status of the bacteria and the characteristics of their closest environmental microniches. We are doing this in collaboration with leading scientists internationally, and using state-of-the-art technologies including Raman spectroscopy, OrbiSIMS and optical nanosensors. We are also investigating specific virulence strategies. Autotransporter proteins are the largest family of bacterial secreted proteins, and all of those characterized to date are virulence factors. One area we study is the characterization of the secretion pathway they use to exit the cell in the molecular detail. The second project focuses on cell-cell signaling molecules involved in population density related gene regulation. The bacteria we are studying include Pseudomonas aeruginosa, Escherichia coli and Staphylococcus. We have two translational projects, one focuses on studying single bacterial cells in real time during skin infections using our range of infection models that include polymicrobial communities, and the other aims to design and build novel interactive devices to help children wash their hands effectively, and thereby avoid spreading dangerous infectious agents.
I have extensive experience in molecular microbiology, including imaging, protein biochemistry and genetic engineering. I have also been involved in numerous studies of gene regulation and more recently am becoming familiar with analytical chemistry techniques aimed at elucidating the metabolome of bacteria. Furthermore, I am expanding my knowledge of tissue engineering and vibrational spectroscopy alongside developing mechanisms to commercialise my research.
To convey knowledge about bacterial pathogenicity and to provide pastoral support and mentor students
Protein secretion enables the bacterium to place a battery of offense (toxins, proteases, etc) and defense (flagella, S-layers) systems beyond the boundaries of their outermembrane. The question `how do such large, sometimes folded structures exit the bacterial cell without causing cell leakage?' is fascinating, but little is known about the mechanics involved. I am interested in characterising these machineries in respect to autotransporter proteins, and determining their role in infection. Gene regulation (particularly that of virulence factors) plays a major role in cell survival and pathogenesis by controlling cell fitness and virulence. My group investigates the integration of metabolism with cell-cell communication, in particular in biofilms to understand the fitness and antimicrobial resistance of bacteria and how this impacts upon pathogenesis. The aim is to uncover and develop novel antimcirobial strategies.
SINGH N, ROMERO M, TRAVANUT A, MONTEIRO PF, JORDANA-LLUCH E, HARDIE KR, WILLIAMS P, ALEXANDER MR and ALEXANDER C, 2019. Dual bioresponsive antibiotic and quorum sensing inhibitor combination nanoparticles for treatment of Pseudomonas aeruginosa biofilms in vitro and ex vivo. Biomaterials science. 7(10), 4099-4111 RUPARELL A, DUBERN JF, ORTORI CA, HARRISON F, HALLIDAY NM, EMTAGE A, ASHAWESH MM, LAUGHTON CA, DIGGLE SP, WILLIAMS P, BARRETT DA and HARDIE KR, 2016. The fitness burden imposed by synthesising quorum sensing signals. Scientific reports. 6, 33101 LARY, D., CALVERT, A., NERLICH, B., SEGAL, J., VAUGHAN, N., RANDLE, J. and HARDIE, K. R., 2019. Improving children’s and their visitors’ hand hygiene compliance: Journal of Infection Prevention Journal of Infection Prevention.
LUCKETT, J.C.A., DARCH, O., WATTERS, C., ABUOUN, M., WRIGHT, V., PAREDES-OSSES, E., WARD, J., GOTO, H., HEEB, S., POMMIER, S., RUMBAUGH, K.P., CÁMARA, M. and HARDIE, K.R., 2012. A novel virulence strategy for Pseudomonas aeruginosa mediated by an autotransporter with arginine-specific aminopeptidase activity PLoS Pathogens. 8(8), e1002854
My Career has focused on the mechanism of bacterial protein secretion, its regulation and relevance to pathogenicity with the overall aim to discover novel antimicrobials. In Cambridge I worked with Profs Colin Hughes and Vassilis Koronakis on the type I dependent secretion of haemolysin (HlyA) from E. coli. Then, in Canada with Prof Tom Buckley on the type II dependent secretion of aerolysin by Aeromonas hydrophila. Moving to Institut Pasteur, Paris with Tony Pugsley, I switched to study the secretion apparatus, concentrating on the outer membrane component GspD and associated GspS. Subsequently I have studied AHL-dependent quorum sensing with Paul Williams (Nottingham) and the survival of H. pylori exposed to different stress conditions, particularly iron availability and oxidative stress, with the aim of discovering the function of the NapA protein (with Robert Logan and Peter Jenks). In collaboration with John Atherton I was involved in characterizing the link between the two major virulence factors of H. pylori (Vacuolating cytotoxin and Cag pathogenicity Island). Motility is an important virulence factor for H. pylori, and in collaboration with Dr Liz Sockett (Department of Genetics) and Klaus Winzer I studied the role of FlhB in flagella assembly and function. The secretion of botulinum toxins via the flagella of Clostridia was investigated with Nigel Minton, and in collaboration with Christoph Tang (Imperial College), Prof Paul Williams (Nottingham), Prof John Atherton (Nottingham), Prof Jerry Wells (Holland) and Klaus Winzer (Nottingham), we studied the role of quorum sensing (cell-cell communication) in H. pylori, C. jejuni, P. aeruginosa, and N. meningitidis, linking this to pathogenicity. With the help of Dave Barrett (Nottingham) we also linked quorum sensing signal molecule production to its impact on cellular metabolism and the consequences this has to cell fitness and virulence (with Nigel Halliday, Cath Otori, Jean Dubern, Avika Ruparell). A major part of my research has focused on the mechanism of autotransporter protein secretion in E. coli (with Jeni Luckett [Nottingham], Rob Delahay [Nottingham], Ian Henderson [Australia] and Luis Angel Fernandez Herrero [Madrid]), Pseudomonas aeruginosa (with Miguel Camara [Nottingham], Stephan Heeb [Nottingham], and Alain Filloux [Imperial College]), Bordetella pertussis (Francoise Jacob Dubuisson [Lille]) and H. pylori (Paul O'Toole, Ireland). Together we aimed at dissecting the roles of potential accessory proteins in this process. With Joel Segal (Engineering Nottingham), Jacqueline Randle and Natalie Vaughan (Nursing ), and Brigitte Nerlich (Nottingham) , I have developed interactive ways of improving the hand hygiene of children and integrated this with a range of outreach activities including the Royal Society Summer Exhibition 2019 with Morgan Alexander [Nottingham]..
I shall continue to study aspects of quorum sensing, metabolism and bacterial protein secretion. In addition I am looking forward to a new project centred around determining simultaneous measurement of transcription, translation and metabolism during human skin infection and in polymicrobial biofilms.