Chronic <i>Pseudomonas aeruginosa</i> lung infection in aged mice via agar beads delivery

Pulmonary infections pose significantly greater threats to the elderly than to younger populations. At the same time, <i>Pseudomonas aeruginosa</i>, a major opportunistic pathogen, frequently causes a typical bacterial chronic infection in clinically vulnerable elderly individuals. To understand the underlying mechanisms of chronic infection in the elderly, a reliable and stable model using aged mice is essential. However, initial attempts using intratracheal instillation of planktonic <i>P. aeruginosa</i> caused 100% mortality, prompting us to optimize current infection methodology in regular young mice. By embedding bacteria in agar beads for intratracheal delivery, we successfully established persistent <i>P. aeruginosa</i> colonization with significantly improved survival. This model provides a crucial platform for elucidating the molecular mechanisms of host-pathogen interactions during chronic infection in the context of aging. Additionally, it offers vital insights into age-specific immune responses against pulmonary bacterial infections and facilitates the development of novel therapeutic strategies tailored for the elderly population.