The present invention relates to reagents and methods for the modulation of viability of bacteria. A process is provided wherein a protein sequence from A. americanum saliva effective in reducing the viability of gram positive, gram negative, or acid-fast bacteria and spirochetes including B. burgdurferi is administered. The inventive protein from A. americanum saliva has utility as a therapeutic for the treatment of an organism infected with bacteria, particularly the spirochete B. burgdorferi.
