The construction of a family of rapid and sensitive assays for Salmonella and other pathogenic bacteria is proposed. Two model assays, based upon the transduction of bacterial ice nucleation genes by genetically engineered bacteriophages, have already been produced, and shown to function as predicted. However, these assays were constructed using well characterized phages; the construction of assays from poorly characterized phages with desirable biological specificities presents a more formidable task. Therefore, it is proposed that during Phase I of the research a family of selectable transposons, based on Tn5 and optimized for mutagenesis of bacteriophages, will be developed and characterized. The most effective of these transposons will be used to rapidly identify regions of phage DNA which are suitable targets for introduction of an ice nucleation reporter gene. During Phase II, this transposon identification method will be used to construct a set of phages which together identify all of the clinically important serotypes of Salmonella.
