Louis Pasteur continues to shape the future of microbiology.

Louis Pasteur made seminal discoveries in microbiology, immunology and vaccinology that transformed clinical science and saved millions of lives. Since the 19th century, our ability to study infectious disease has undergone radical changes due to newly emerging technologies and infection models. In this Editorial, I consider Pasteur's impact on our ability to understand and combat infectious disease in the context of two modern-day pandemics: coronavirus disease 2019 (COVID-19) and antimicrobial resistance (AMR). During the COVID-19 pandemic, we witnessed remarkable ambition to understand severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and to innovate effective vaccines to prevent disease. For the comparatively overlooked pandemic of AMR, we require the same level of urgency to develop alternative approaches to combat antibiotic-resistant bacterial strains that cause millions of deaths annually. Pasteur's statement "chance only favours the mind which is prepared" is a principle that captures 'l'esprit Pasteur'. This principle should continue to guide modern-day research on infectious disease, and for this we need to support the development of predictive disease models and cutting-edge mechanistic research that prepare us for discovery and therapeutic impact.