Infectious diseases are now the second major cause of death worldwide and the third leading cause of death in developed countries.
The global market for antibiotic sales in 2005 was worth $28Bn, of which the US had a 35% market share – figures that are set to rise by at least 4% per annum for the foreseeable future.
The oversubscription of antibiotics, particularly in hospitals has caused a steep rise in the rates of bacterial resistance. Existing antibiotics are no longer effective in all cases and treatment options for certain microorganisms have become scarce, particularly with the Gram negatives.
Acute bacterial infections such as methicillin resistant Staphylococcus aureas (MRSA) account for over half the infections in intensive care units in the US alone, with an estimated 300,000 people contracting the infection each year and resulting in 12,000 deaths. A recent study by the National Nosocomial Infections Surveillance (NNIS) System (part of the Centres for Disease Control (CDC) in the USA) showed that in 2005, 63% of all Staphylococcus infections were resistant to treatment, representing an 11% increase over the previous 5 years. More disturbing is the thought that within a few years, all clinical isolates of Staphylococcus aureus infections will be classed as community –associated methicillin resistant.
The ability of bacteria to readily evade any form of established therapy remains a constant in antimicrobial treatment and pathogens that are resistant to one or more antibiotics are emerging and spreading worldwide. The treatment for these and other emerging infections must be the development and use of novel antibiotic therapies.
Although a number of new anti-Gram-negative antibacterial agents are likely to be introduced soon for clinical use, they will not represent a quantum leap in the ability to effectively treat these human pathogens. Antibacterials are the only class of therapeutic in which drugs of last-resort have become first-line therapy.
New classes of antimicrobials with novel mechanisms of action and new approaches to increasing the effectiveness of traditional antimicrobials are urgently needed.