Professor Digby Warner

Professorial Director of the Institute of Infectious Disease and Molecular Medicine

Affiliations

  1. Full Member, Institute of Infectious Disease and Molecular Medicine
  2. Discovery Research Platform for Infection (CIDRI-Africa)
  3. Division of Medical Microbiology, Department of Pathology
  4. Faculty of Health Sciences, University of Cape Town

Key Expertise

TB transmission, Tuberculosis, Drug Discovery, Drug Resistance, Pathogenesis

Main Research Focus

Digby Warner is a molecular mycobacteriologist whose research aims to elucidate fundamental aspects of Mycobacterium tuberculosis physiology and metabolism, especially the molecular mechanisms that underlie the evolution and propagation of drug resistance. To that end, he has focused on DNA repair and replication pathways in M. tuberculosis and their potential involvement in the emergence of drug resistance; the role of vitamin B12 and B12-dependent pathways in mycobacterial metabolism; and the impact of drug resistance on mycobacterial physiology.

Together with his close collaborator, Professor Robin Wood, he leads research which aims to provide detailed insights into the host, environmental, and mycobacterial factors that enable M. tuberculosis transmission. That work, which operates at the interface of clinical and fundamental mycobacteriology, has provided the motivation to develop microscopy and imaging tools enabling detection, single-cell analyses, and cytological profiling of bacilli derived from a variety of clinical samples, including post-mortem tissue.

Most Significant Paper Authored in 2024

Aerosolization of viable Mycobacterium tuberculosis bacilli by tuberculosis clinic attendees independent of sputum-Xpert Ultra status (2024)

Patterson, B., Dinkele, R., Gessner, S., Koch, A., Hoosen, Z., January, V., Leonard, B., McKerry, A., Seldon, R.,Vazi, A., Hermans, S., Cobelens, F., Warner, D. F., & Wood, R. (2024)


This paper reported the detection of Mycobacterium tuberculosis (Mtb)-positive bioaerosols in ~90% of individuals presenting to a community clinic with presumptive tuberculosis (TB), irrespective of final TB diagnosis. Even more surprisingly, the rates of decline in symptom prevalence and Mtb bioaerosol release in TB patients undergoing standard chemotherapy were equivalent to those with a negative TB diagnosis. Consistent with previous observations, ~20% of participants remained Mtb bioaerosol-positive after six months regardless of treatment. The spontaneous clearance of detectable Mtb infection among untreated individuals was unexpected, raising the possibility that periodic cycling between asymptomatic and symptomatic subclinical disease states might occur frequently.