In one example embodiment, a system for treating a tissue site is disclosed comprising a dressing adapted to contact the tissue site and provide a fluid seal between a therapeutic environment and a local external environment, and a solution source fluidly coupled to the dressing and adapted to deliver an antimicrobial solution comprising a peroxy α-keto carboxylic acid, such as peroxy pyruvic acid, to the tissue interface. The system may further comprise a negative-pressure source fluidly coupled to the dressing and adapted to provide negative pressure to the therapeutic environment after delivery of the antimicrobial fluid to the therapeutic environment. In another example embodiment, a method for treating a tissue site is disclosed comprising positioning a tissue interface to contact the tissue site, covering the tissue interface and the tissue site with a drape to provide a fluid seal between the therapeutic environment and the local external environment, and delivering an antimicrobial solution comprising peroxy α-keto carboxylic acid to the therapeutic environment before providing negative pressure to the therapeutic environment.