VDEC has developed a standardized assay to reduce the development of antimicrobial resistance and improve treatment of tuberculosis patients.
Executive Summary
The Vaccine Development and Evaluation Center (VDEC) has developed a standardized assay as a tool to screen libraries of compounds against Mycobacterium tuberculosis in conjunction with a commonly used chemotherapy drug, to reduce the development of antimicrobial resistance (AMR) and, hopefully , improve patient treatment.
Target
Tuberculosis caused by M. tuberculosis causes 1.6 million deaths per year. High levels of drug resistance make tuberculosis treatment particularly difficult and contribute to the growing threat of antimicrobial resistance (AMR). To meet the WHO goal of ending tuberculosis by 2035, we urgently need new therapies that reduce treatment time and include strategies that target AMR Mycobacterium tuberculosis.
Aims
An important goal for improving tuberculosis treatment is to shorten the period of antibiotic therapy without increasing relapse rates or encouraging the development of antibiotic-resistant strains. Pyrazinamide (PZA) is a key component of first-line chemotherapy against M. tuberculosis and plays an essential role in the shortened 6-month treatment period. Increasing PZA activity could reduce the emergence of resistance, shorten treatment times, and lead to a reduction in the amount of PZA consumed by patients, thereby reducing toxic effects.
Problems
In vitro assessments of PZA are often avoided due to lack of standardization, which has led to a lack of effective in vitro tools to assess/increase PZA activity.
Options
We addressed this gap by first defining the conditions for assessing PZA in model fermenters that replicate the acidic conditions under which PZA is active (1) and second by applying this knowledge to the development of a standardized assay to track active molecules. and perform additional characterization.
VDEC’s unique capability
Through a collaborative project with industrial partners, we screened large compound libraries (defined as having more than 80,000 compounds) to find molecules that improve the effectiveness of PZA, thereby reducing toxicity and extending its shelf life. This approach is being applied by the team to screen libraries of compounds against other AMR pathogens, including:
Pseudomonas aeruginosa
Neisseria gonorrhoeae Carbapenem-resistant
Mycobacterium abscessus Enterobacterales viral threats such as coronavirus Coalition for Epidemic Preparedness Innovations (CEPI) priority pathogens We are the only research group in the UK using a combination of fermentation, molecular methods and screening assays high-throughput systems (HTS) for drug discovery and evaluation in pathogenic bacteria.
Details and priorities
The Discovery team at the UK Health Security Agency (UKHSA), Porton Down, focuses on the discovery and development of therapeutics for AMR, addressing fundamental questions about drug resistance and antigen discovery through to assessment pre-clinical development of new and existing antimicrobials in collaboration with academia, the public sector and industry worldwide. To achieve our goals, the team has developed new, disease-relevant, defined growth models and rare technologies, ranging from fermenter models to rapid, modernized, high-throughput assays to determine antimicrobial activity.
Result
The team discovered results that potentiate PZA and is now characterizing them and determining their mode of action against M. tuberculosis.
Future work
The test method has been accepted for publication ( 2 ).
References
Steven T. Pullan, Jon C. Allnutt, Rebecca Devine, Kim A. Hatch, Rose E. Jeeves, Charlotte L. Hendon-Dunn, Philip D. Marsh, Joanna Bacon. “The effect of growth rate on pyrazinamide activity in Mycobacterium tuberculosis – insights for early bactericidal activity?” (2016) BMC Infectious Diseases 16: 205
Christopher W. Moon, Eleanor Porges, Stephen C. Taylor, and Joanna Bacon. “An acidic pH microtiter plate assay to identify potentiators that increase the activity of pyrazinamide against Mycobacterium tuberculosis. (chapter) Antibiotic Resistance Protocols, 4th Edition (2024) Springer Protocols, Humana Press.
