Abstract: The present invention relates generally to targeted molecular agents (TMAs) directed to a particular organism or group of organisms and uses thereof. More particularly, the present invention provides TMAs having a targeting moiety which comprises a natural or induced auxotrophic requirement of the particular organism as a vehicle for directing an agent linked to the moiety to be delivered to the target organism. The TMAs of the present invention are useful for targeting molecules such as antimicrobial agents and diagnostic agents to selected organisms.

Abstract: The present invention relates generally to a method for the prophylaxis and treatment of infection by microorganisms in biological environments from where the microorganisms acquire iron, heme or porphyrin, generally but not exclusively for growth. Particular biological environments contemplated by the present invention include but are not limited to vascular regions and cavities as well as mucosal membranes in animals including mammals, reptiles, amphibians and fish and in avian species as well as hooves of livestock animals. The method of the present invention involves interrupting, reducing or otherwise antagonizing the interaction between a microbial-derived polypeptide, such as but not limited to a polypeptide having cysteine proteinase activity, and a porphyrin-containing molecule in such as heme.