Antimicrobial compositions for oral delivery, and administration to the colon, distal
ileum, or other portion of the
gastrointestinal tract other than the
stomach, of
bacteriophage, phage proteins,
antimicrobial peptides, or
antimicrobial aptamers, are disclosed. In one embodiment, the
active agent is capable of lysing the bacterial
cell wall. In another embodiment, the
active agent is capable of interacting with a
receptor or
enzyme in the
bacteria. In some embodiments, the active agents selectively act on one or more harmful
bacteria, such as
Clostridium difficile, and either do not act, or act to a lesser extent, on helpful
bacteria, such as bifidobacteria. When the agents are not delivered directly to the colon, they active agents ultimately enter the colon and affect the bacteria that are present in the colon. The compositions can include beads of
pectin in the form of a cationic salt enclosing the
active agent, or other types of
drug delivery systems designed for targeted delivery to the desired portion of the
gastrointestinal tract.