Fig. 1. Diagram representing the oropharyngeal aspiration technique for the development of a lung challenge model in mice. Once anaesthetized, the mouse is placed on a metal backboard (a) in a semi-recumbent supine position (b) and suspended by the upper incisors from a thread (c). The nares are then occluded (d), and the tongue is gently pulled outside the mouth using blunt tweezers (e) by one person. An aliquot of 50 µl of either a bacterial suspension or PBS is deposited by the second person into the oral cavity (f) as close as possible to the entrance of the trachea with a P200 pipette and filter tips. The mouse is allowed to aspirate the inoculum for at least ten breaths, while respiration is monitored both visually and aurally, after which the tongue and the nares are released, and the mouse is allowed to recover in the cage’s bedding.
