Molecular subtyping scheme for Salmonella panama

Abstract

We describe a genotyping scheme for Salmonella panama. Defined probes specific for the 16S rRNA gene and the DNA insertion element IS200 were generated by PCR from S. panama and were used to probe genomic Southern blots made with enzymes selected to cut within and outside the probed sequences. Plasmid profiles were determined. The typeability and discriminatory power of the individual methods were compared. Ribotyping with 16S rRNA gene probe alone was slightly more discriminatory than phage typing, but unlike the latter, ribotyping was able to type all strains. IS200 profiling was the single most discriminatory method for S. panama, having an index of discrimination (D) of 0.8 and 100% typeability. Plasmid profiling, which had moderate discriminatory power but only 50% typeability, was valuable as an adjunct technique. The use of all three methods together or simply the combination of IS200 profiling with the two most discriminatory enzymes and plasmid profiling yielded a molecular typing scheme whose discriminatory power (D = 0.97) approached the maximum theoretical value. This should prove both useful and robust for epidemiological investigations of S. panama.