Methods and Models for Studying Mycobacterium tuberculosis in Respiratory Infections

Respiratory infections, including tuberculosis, constitute a major global health challenge. Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains one of the leading causes of mortality worldwide. The disease's complexity is attributed to Mtb's capacity to persist in latent states, evade host immune defenses, and develop resistance to antimicrobial treatments, posing significant challenges for diagnosis and therapy. Traditional models, such as animal studies and two-dimensional (2D) in vitro systems, often fail to accurately recapitulate human-specific immune processes, particularly the formation of granulomas-a defining feature of tubercular infection. These limitations underscore the need for more physiologically relevant models to study TB pathogenesis. Emerging three-dimensional (3D) in vitro systems, including organoids and lung-on-chip platforms, offer innovative approaches to mimic the structural and functional complexity of the human lung. These models enable the recreation of key aspects of the tubercular granulomas, such as cellular interactions, oxygen gradients, and nutrient limitations, thereby providing deeper insights into Mtb pathogenesis. This review aims to elucidate the advantages of 3D in vitro systems in bridging the translational gap between traditional experimental approaches and clinical applications. Particular emphasis is placed on their potential to address challenges related to genetic variability in both the host and pathogen, thereby advancing tubercular research and therapeutic development.