Combatting β-lactamase-mediated antimicrobial resistance: from novel assays for inhibitor discovery to new diagnostics

The clinical utility of β-lactams, the most prescribed antibiotics worldwide, is endangered due to the production of β-lactamase enzymes by pathogenic bacteria. Collectively, these enzymes can inactivate every clinically available β-lactam antibiotic via a hydrolytic mechanism. Thus, infections caused by β-lactamase-producing bacteria are associated with markedly high mortality rates. Combatting β-lactamase-mediated antimicrobial resistance requires efforts in developing novel technologies for the discovery of new therapeutics, as well as diagnostic tests which can rapidly identify β-lactamase-producing pathogens. To address this need, we developed a novel whole-cell biosensor-based platform which can facilitate the discovery of β-lactamase inhibitors, compounds which are administered alongside a β-lactam antibiotic to protect them from β-lactamase-mediated hydrolysis. This platform was validated using a panel of clinically relevant β-lactamases and was applied to quantitatively study the potency of a selection of clinically used inhibitors, as well as non-clinical compounds reported in the literature. This method prioritizes hits which exhibit activity against cellular β-lactamases and can account for factors like drug permeability and efflux. We also developed two novel luminescent and colourimetric-based diagnostic assays for the rapid detection of carbapenemase-producing Enterobacterales, bacterial pathogens which are resistant to the last-resort carbapenem antibiotics. These assays were validated with a panel of clinical isolates producing carbapenemases that are most commonly encountered by clinical microbiology labs. When challenged with these panels, both assays exhibited a high degree of sensitivity (97.5 % and 100 %, respectively) and specificity (100 % and 100 %, respectively). Due to the rapid turnaround times (2.5 h and 3.5 h, respectively), minimal setup requirements, and high sensitivity, these diagnostics could serve as attractive alternatives to currently employed detection methods, which suffer from long turnaround times or poor sensitivity for certain carbapenemases. Additionally, the colourimetric assay does not require any specialized lab equipment and thus could be suitable for implementation in resource-constrained settings. Providing clinical care teams with rapid results will ensure that patients suffering from infections caused by carbapenemase-producing pathogens will receive timely and appropriate antimicrobial therapy, and that infection prevention and control measures are put in place to prevent outbreaks in clinical settings.

Department dc:contributor.department

Biomedical and Molecular Sciences

Year dc:date.issued

2025

Author dc:creator

• Jeffs, Mitchell

Advisor dc:contributor.supervisor

• Lohans, Christopher

• Antibiotic resistance
• Microbiology
• Molecular Biology

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1974/35323

OAI identifier oai:identifier

oai:queensu.scholaris.ca:1974/35323