Described herein are new approaches to antimicrobial therapy, which includes the development of new combinations of antibiotic agents as well as their use for specific therapeutic purposes. These specific therapeutic purposes may apply to clinical situations inherently different from treatment of infections that require systemic antibiotic administration. More localized approaches offer a number of advantages. The advantages of such antibiotic combinations include, but are not limited to, targeting a broader spectrum of microbes； faster microbial eradication； sparing the subject systemic exposure to the individual antimicrobial agents； enhancing the antimicrobial activity against microbes considered resistant to individual agents； and enhancing the antimicrobial activity against microbes considered resistant to individual agents at levels appropriate for systemic administration.
