Virulence gene expression in vivo.

The ability to identify and isolate bacterial RNA from animals or humans with infections has markedly advanced the capacity to examine microbial gene expression in vivo. This advance has been coupled with the development of quantitative real-time reverse transcription polymerase chain reaction and expression microarrays to allow investigators to accurately measure how organisms are manipulating their genetic expression during actual infections. Though the full ramifications of these technologies have yet to be realized, they promise to open new avenues of therapeutics for a broad range of infectious diseases by allowing researchers to focus on in vivo expressed genes. These developments provide a framework for efficient utilization of the vast amount of information being generated by the accelerating pace of genomic sequencing of microbes.