Imperial College London

ProfessorDariusArmstrong-James

Faculty of MedicineDepartment of Infectious Disease

Professor of Infectious Diseases and Medical Mycology
 
 
 
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Contact

 

d.armstrong

 
 
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Location

 

Flowers buildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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130 results found

Shirkhani K, Teo I, Armstrong-James D, Shaunak Set al., 2015, Nebulised amphotericin B-polymethacrylic acid nanoparticle prophylaxis prevents invasive aspergillosis, NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE, Vol: 11, Pages: 1217-1226, ISSN: 1549-9634

Journal article

Abdolrasouli A, Rhodes J, Beale M, Hagen F, Rogers TR, Chowdhary A, Meis JF, Armstrong-James, Fisher MCet al., 2015, Genomic context of Azole-resistance mutations in Aspergillus fumigatus using whole-genome sequencing, mBio, Vol: 6, ISSN: 2161-2129

A rapid and global emergence of azole resistance has been observed in the pathogenic fungus Aspergillus fumigatus over the past decade. The dominant resistance mechanism appears to be of environmental origin and involves mutations in the cyp51A gene, which encodes a protein targeted by triazole antifungal drugs. Whole-genome sequencing (WGS) was performed for high-resolution single-nucleotide polymorphism (SNP) analysis of 24 A. fumigatus isolates, including azole-resistant and susceptible clinical and environmental strains obtained from India, the Netherlands, and the United Kingdom, in order to assess the utility of WGS for characterizing the alleles causing resistance. WGS analysis confirmed that TR34/L98H (a mutation comprising a tandem repeat [TR] of 34 bases in the promoter of the cyp51A gene and a leucine-to-histidine change at codon 98) is the sole mechanism of azole resistance among the isolates tested in this panel of isolates. We used population genomic analysis and showed that A. fumigatus was panmictic, with as much genetic diversity found within a country as is found between continents. A striking exception to this was shown in India, where isolates are highly related despite being isolated from both clinical and environmental sources across >1,000 km; this broad occurrence suggests a recent selective sweep of a highly fit genotype that is associated with the TR34/L98H allele. We found that these sequenced isolates are all recombining, showing that azole-resistant alleles are segregating into diverse genetic backgrounds. Our analysis delineates the fundamental population genetic parameters that are needed to enable the use of genome-wide association studies to identify the contribution of SNP diversity to the generation and spread of azole resistance in this medically important fungus.

Journal article

Bertuzzi M, Schrettl M, Alcazar-Fuoli L, Cairns TC, Muñoz A, Walker LA, Herbst S, Safari M, Cheverton AM, Chen D, Liu H, Saijo S, Fedorova ND, Armstrong-James D, Munro CA, Read ND, Filler SG, Espeso EA, Nierman WC, Haas H, Bignell EMet al., 2015, Correction: The pH-Responsive PacC Transcription Factor of Aspergillus fumigatus Governs Epithelial Entry and Tissue Invasion during Pulmonary Aspergillosis., PLoS Pathog, Vol: 11

Journal article

Shah A, Abdolrasouli A, Soresi S, Herbst S, Reed A, Carby M, Thornton CR, Drumright L, Shaunak S, Armstrong-James Det al., 2015, The Utility of Novel Multi-Stage Testing for the Diagnosis of Pulmonary Aspergillosis in a Cohort of Lung Transplant Recipients, 35th Annual Meeting and Scientific Sessions of the International-Society-for-Heart-and-Lung-Transplantation, Publisher: ELSEVIER SCIENCE INC, Pages: S306-S306, ISSN: 1053-2498

Conference paper

Herbst S, Shah A, Moya MM, Marzola V, Jensen B, Reed A, Birrell MA, Saijo S, Mostowy S, Shaunak S, Armstrong-James Det al., 2015, Phagocytosis-dependent activation of a TLR9-BTK-calcineurin-NFAT pathway co-ordinates innate immunity to Aspergillus fumigatus, EMBO Molecular Medicine, Vol: 7, Pages: 240-258, ISSN: 1757-4676

Transplant recipients on calcineurin inhibitors are at high risk of invasive fungal infection. Understanding how calcineurin inhibitors impair fungal immunity is a key priority for defining risk of infection. Here, we show that the calcineurin inhibitor tacrolimus impairs clearance of the major mould pathogen Aspergillus fumigatus from the airway, by inhibiting macrophage inflammatory responses. This leads to defective early neutrophil recruitment and fungal clearance. We confirm these findings in zebrafish, showing an evolutionarily conserved role for calcineurin signalling in neutrophil recruitment during inflammation. We find that calcineurin–NFAT activation is phagocytosis dependent and collaborates with NF‐κB for TNF‐α production. For yeast zymosan particles, activation of macrophage calcineurin–NFAT occurs via the phagocytic Dectin‐1–spleen tyrosine kinase pathway, but for A. fumigatus, activation occurs via a phagosomal TLR9‐dependent and Bruton's tyrosine kinase‐dependent signalling pathway that is independent of MyD88. We confirm the collaboration between NFAT and NF‐κB for TNF‐α production in primary alveolar macrophages. These observations identify inhibition of a newly discovered macrophage TLR9–BTK–calcineurin–NFAT signalling pathway as a key immune defect that leads to organ transplant‐related invasive aspergillosis.

Journal article

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