ProfessorGadFrankel

Summary

MOLECULAR PATHOGENESIS: GRAM-NEGATIVE BACTERIAL PATHOGENS AND AMR

 We have several intertwined research streams:

EPEC AND EHEC PATHOGENESIS AND HOST RESPONSES

We investigate infections with enterohaemorrhagic Escherichia coli (EHEC), which causes haemorrhagic colitis and haemolytic uraemic syndrome (HUS), and enteropathogenic E. coli (EPEC), which causes paediatric diarrhoea mainly in low and middle-income countries. EPEC and EHEC employ a type III secretion system (T3SS) to inject dozens of effectors that take control of cell signaling (1,2). We study the structure and function of the effectors (for example 3,4).

Mice are inherently resistant to EPEC and EHEC infection. For this reason we extensively make use of the related mouse pathogen Citrobacter rodentium, which shares an infection strategy and effectors with EPEC and EHEC (5,6). In particular, we investigate the impact of C. rodentium infection on infected intestinal epithelial cells (IECs) in vivo using isobaric labelling proteomics, targeted metabolomics and lipidomics. We also study the impact of C. rodentium infection on the composition of faecal and mucosal associated gut microbiota.

EHEC, EPEC and C. rodentium colonise the gut mucosa via formation of attaching and effacing lesions.

Infections with Salmonella Typhi belonging to haplotype H58

Salmonella enterica serovar Typhi (S. Typhi) cause the systemic disease, typhoid fever. Its virulence depends on the activity of two T3SSs carried on Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2), which secrete a pool of over 40 effectors to subvert host cell processes to permit immune evasion, invasion, and intracellular growth. The need to better understand S. Typhi infection has been intensified by the recent spread of haplotype 58 (H58), also known as 4.3.1, that has clonally expanded worldwide to become the dominant cause of multi-drug resistant (MDR) typhoid across South and Southeast Asia and East Africa. We are aiming to understand the reasons underlying the relative success of H58 strains (7,8).

Differential SPI-1 gene expression between S. Typhimurium,
S. Typhi Ty2 and S. Typhi belonging to the H58 clade

EXTENSIVELY DRUG RESISTANT KLEBSIELLA PNEUMONIAE IN THE HUMAN LUNG

Klebsiella pneumoniae is an established human pathogen typically affecting hospitalised patients although an invasive community-acquired disease is also emerging in the far east. The rapid emergence of carbapenemase producing strains is the latest wave antimicrobial resistance mechanism among Gram-negative bacteria. In the United Kingdom, Klebsiella pneumoniae is now the most prevalent carbapenemase producing invasive isolate detected in patients. This project characterises large epidemic resistance plasmids in Klebsiella and their impact of virulence and persistence in mice to help understand the proliferation and spread of these resistance determinants. In vivo imaging is used to spatio-temporally track infection coupled with prokaryotic transcriptomics to identify novel targets for antimicrobial chemotherapy.  

Antimicrobial resistance and tracking commensal E. coli

We face a growing threat from the spread of antimicrobial resistance and an on-going high burden of diarrhoeal diseases, particularly in young children. To address these challenges we use mouse models to investigate the impact of infection with ETEC, the effect of antibiotic treatments on the gut physiology and the microbiota, the consequences of treating infections with antibiotic resistant pathogens, and to track commensal E. coli in vivo under various stress conditions (e.g. infection, inflammation, diet). These studies benefit significantly from our in vivo imaging capability.

3D imaging of a mouse infected with bioluminescent C. rodentium 

^{Cover illustration created by Agnes Sågfors, who also designs and produces art for many of our published figures.}

These projects are supported by a cross council grant “tackling AMR Theme 1: Understanding resistant bacteria in context of the host” and by a Royal Society International Collaboration Awards for Research Professors.

^{1. Garmendia, J., Frankel, G., and Crepin, V.F. Enteropathogenic and enterohemorrhagic E. coli infections: translocation, translocation, translocation. Infect. Immun. 73 (2005), 2573-2585}

^{2. Raymond, B., Young, J.C., Pallett, M., Endres, R.G., Clements, A., and Frankel, G. Subversion of trafficking, apoptosis and innate immunity by type III secretion system effectors. Trends Microbiol. 21 (2013), 430-441}

^{3. Young, C., Clements, A., Lang, A.E., Garnett, J.A., Munera, D., Arbeloa, A., Pearson, J., Hartland, E.L., Matthews, S.J., Mousnier, A., Barry, D.J., Way, M., Schlosser, A., Aktories, K., and Frankel, G. The E. coli effector EspJ blocks Src kinase activity via amidation and ADP-ribosylation. Nat Comm. 5 (2014), 5887}

^{4. Pearson, J.S., Giogha, C., Ong, S.Y., Kennedy, C.L., Kelly, M., Robinson, K.S., Wong, T., Mansell, A., Riedmaier, P., Oates, C.V.L, Zaid, A., Mühle, S., Crepin, V.F., Marches, O., Ang, C.H., Williamson, N.A., O’Reilly, L.A., Bankovacki, A., Nachbur, U., Infusini, G., Webb, A.I., Silke, J., Strasser, A., Frankel, G., and Hartland, E.L. A type III effector antagonises death receptor signalling during bacterial gut infection. Nature 501 (2013), 247-251}

^{5. Collins, J.W., Keeney, K.M., Crepin, V.F., Rathinam, V.A.K., Fitzgerald, K.A., Finlay, B.B., and Frankel, G. Citrobacter rodentium: infection, inflammation and the microbiota. Nat. Rev. Microbiol. 12 (2014), 612-623}

^{6. Crepin, V.F., Collins, J., Habibzay, M., and Frankel, G. Citrobacter rodentium mouse model of bacterial infection. Nature Protocols 11 (2016), 1851–1876}

^{7. Johnson, R., Byrne, A., Berger, C.N., Klemm, E., Crepin, V.F., Dougan, G., and Frankel, G. The type III secretion system effector SptP of Salmonella enterica serovar Typhi. J. Bacteriol. (2016), DOI: 10.1128/JB.00647-16.}

^{8. Johnson, R. , Ravenhall, M,, Pickard, D., Dougan, G., Byrne, A. and Frankel, G. Comparison of Salmonella enterica Serovars Typhi and Typhimurium Reveals Typhoidal Serovar-Specific Responses to Bile. Infect. Immun. (2018) 86, 3 e00490-17}

Group Members

Professor Gad Frankel
Gad Frankel obtained his B.Sc. in Biology and subsequently his Ph.D in Genetics from the Hebrew University of Jerusalem. He has held a Howard Hughes Fellowship in the Department Microbiology and Immunology, Stanford University, CA, USA. Following a short stay at the Weizmann Institute in Rehovot, he was appointed a research fellow at Imperial College. In 1998 he was appointed Lecturer at Imperial College, was promoted to Reader in 2000 and to Professor in 2002. He is currently Professor of Bacterial Pathogenesis at the Department of Life Sciences and the MRC Centre for Molecular Bacteriology and Infection (CMBI) at Imperial College London.

Dr Maria L Alberdi	Dr Sharanya Chatterjee	Dr Louise E Kerry	Dr Carrie Mullineaux Sanders
Research Associate	Research Associate	Laboratory Manager	Research Associate
Dr Julia Sanchez-Garrido	Dr Joshua L C Wong	Ms Jasmine Clark	Ms Eve Hopkins
Research Associate	Clinical Research Training Fellow	PhD Student	PhD Student
Ms Wen Wen Low	Mr Qiyun Zhong
PhD Student	PhD Student

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