In 2006, worldwide sales of all anti-infective drugs totaled approximately $66.5 billion, with sales of antibiotics accounting for approximately 50% of the total. The overall market is expected to continue its growth and the antibiotic market is expected to reach $45 billion by 2012. This growth is due in large part to the increasing emergence of multi-drug resistant bacterial strains, the deficiencies of currently available antibiotics to treat certain serious bacterial infections and a vulnerable aging population throughout the world’s major markets. The costs associated with managing antibiotic resistance in the U.S. have reached an estimated $10 billion per year and continue to escalate.