Essential Genes in the Infection Model of Pseudomonas aeruginosa PCR-Based Signature-Tagged Mutagenesis

PCR-based signature tagged mutagenesis is an “en masse” screening technique based upon unique oligonucleotide tags (molecular barcodes) for identification of genes that will diminish or enhance maintenance of an organism in a specific ecological niche or environment. PCR-based STM applied to Pseudomonas aeruginosa permitted the identification of genes essential or in vivo maintenance by transposon insertion and negative selection in a mixed population of bacterial mutants. The innovative adaptations and refinement of the technology presented here with P. aeruginosa STM mutants selected in the rat lung have given critical information about genes essential for causing a chronic infection and a wealth of information about biological processes in vivo. The additional use of competitive index analysis for measurement of the level of virulence in vivo , microarray-based screening of selected prioritized STM mutants coupled to metabolomics analysis can now be attempted systematically on a genomic scale. PCR-based STM and combined whole-genome methods can also be applied to any organism having selectable phenotypes for screening.