Strategies for isolation of in vivo expressed genes from bacteria

The discovery and characterization of genes specifically induced in vivo up on infection and/or at a specific stage of the infection will be the next p hase in studying bacterial virulence at the molecular level. Genes isolated are most likely to encode virulence-associated factors or products essenti al for survival, bacterial cell division and multiplication in situ. Identi fication of these genes is expected to provide new means to prevent infecti on, new targets for antimicrobial therapy, as well as new insights into the infection process, Analysis of genes and their sequences initially discove red as in vivo induced may now be revealed by functional and comparative ge nomics. The new field of virulence genomics and their clustering as pathoge nicity islands makes feasible their in-depth analysis. Application of new t echnologies such as in vivo expression technologies, signature-tagged mutag enesis, differential fluorescence induction, differential display using pol ymerase chain reaction coupled to bacterial genomics is expected to provide a strong basis for studying in vive induced genes, and a better understand ing of bacterial pathogenicity in vive. This review presents technologies f or characterization of genes expressed in vive. (C) 1999 Federation of Euro pean Microbiological Societies. Published by Elsevier Science B.V. All righ ts reserved.