[Problem] To effectively prevent infection in users of a communal facility. [Solution] A system 1 for defending against infection is provided with: a liquid tank 3 that stores an antimicrobial agent a rod-shaped, hollow liquid straw 31, of which the discharge port is kept outside the liquid tank and the suction port is inserted into the tank 3 so as to be immersed in the antimicrobial agent a compressor 2 that compresses air sucked from outside and injects the air from an air nozzle a mist generating chamber 4 that forms a closed space into which the air nozzle and the discharge port of the liquid straw are inserted, wherein a suspended droplet nozzle 41 for discharging the antimicrobial agent, which is suspended in a nebulized form in the closed spaced, is attached to the mist generating chamber 4 at least two columnar nebulizers 6, which internally house a guiding pipe having an opened injection hole 62 a guiding tube 5 that connects the guiding pipe inside the columnar nebulizers to the suspended droplet nozzle of the mist generating chamber and a foot-operated switch 7 that controls the supply of power to the compressor 2, said foot-operated switch 7 being turned on when a load is applied by a users foot-stepping operation, and being turned off when the load is released.Le problème décrit par la présente invention est dempêcher efficacement linfection dutilisateurs dune installation commune. La solution selon linvention porte sur un système (1) de défense contre une infection comprenant : un réservoir (3) de liquide qui stocke un agent antimicrobien une paille creuse (31), en forme de tige, pour le liquide, dont lorifice dévacuation est maintenu à lextérieur du réservoir de liquide et lorifice daspiration est inséré dans le réservoir (3) de manière à être immergé dans lagent antimicrobien un compresseur (2) qui comprime lair aspiré depuis lextérieur et injecte lair à partir dune buse dair une chambre (4) de production de brume qui forme un espace fermé dans l
