Novel targets for antibiotics - an update

Application of combinatorial chemistry to antimicrobial drug discovery

The emergence of pathogens resistant to currently available treatments is seen as a public health crisis. Since few new classes of antimicrobial drugs have been developed in the last two decades, it is becoming increasingly probable that healthcare providers will be faced with infections for which no chemotherapeutic agent is available. A renewed emphasis is being placed on employing the most advanced drug discovery technologies in the development of new antimicrobials. The recently introduced technologies of combinatorial chemistry offer new sources of chemical diversity, as well as methods with which to produce and rapidly test them. In the last few years, many groups have adopted a number of approaches in order to apply combinatorial chemistry to antimicrobial drug discovery. These combinatorial strategies, and the manner in which they are used to develop new screening formats or to identify new chemical leads are, reviewed.

Research and development of antibacterial agents

Several new antibacterial agents are currently being developed in response to the emergence of bacterial resistance to existing drugs. The new agents include compounds that inhibit macromolecular synthesis or interfere with bacterial membrane function. Apart from the oxazolidinones and cationic peptides, the remainder of these new compounds are analogues of earlier antibiotic classes; therefore, it is probable that existing resistance mechanisms will adapt to accommodate the new derivatives. To minimise the potential for emergence of resistance to new agents, research strategies should be chosen that not only enhance the discovery of structurally novel drugs, but also direct these to new molecular targets that may themselves have decreased potential to give rise to drug-resistant variants.

Novel approaches to the discovery of antimicrobial agents

With the completion of numerous bacterial genome sequences, the discovery of antibacterial drugs has fully entered the genomic era. The strategies for effectively using genomic information for target identification, target characterization, screen development and compound evaluation are emerging, and have greatly increased the number of antibacterial targets available for screening. Fortunately, simultaneous efforts in improving miniaturization, robotics and database tools are underway so that the potential of genomics can be realized.