Provided herein are methods of preventing and treating polybacterial infections comprising administering an effective amount of an antibody or antigen-binding fragment thereof that specifically binds to an epitope produced by at least one of the bacterium in the polybacterial infection. For example, an antibody that specifically binds to Staphylococcus aureus alpha toxin can be administered to a patient with a polybacterial infection comprising Staphylococcus aureus and Pseudomonas aeruginosa to inhibit the growth of Pseudomonas aeruginosa.
