Certain embodiments of the invention pertain to a method of treating an infection in a subject caused by an infectious agent other than Escherichia coli, the method comprising administering to the subject arsinothricin or a salt thereof. The infectious agent other than E. coli can be a bacterium, protozoan, helminth, archaebacterium, or a fungus. In preferred embodiments, the infectious agent is Mycobacterium tuberculosis, Mycobacterium bovis, or Enterobacter cloacae. The invention also pertains to a method of treating an infection in a subject caused by an infectious agent, comprising administering to the subject arsinothricin or a salt thereof in combination with an inhibitor of phosphinothricin N-acetyltransferase or arsinothricin N-acetyltransferase. In certain such embodiments, the infectious agent expresses phosphinothricin N-acetyltransferase or arsinothricin N-acetyltransferase. Further embodiments provide compositions comprising arsinothricin or a salt thereof and an inhibitor of phosphinothricin N-acetyltransferase or arsinothricin N-acetyltransferase.