Use of single-strand conformation polymorphism analysis to examine the variability of the rpoS sequence in environmental isolates of Salmonellae.

The natural environment places its resident microflora under stress, which may often result in adaptation by the microflora in order to increase the probability of survival. One such mechanism that has been postulated involves rpoS, which encodes a sigma factor that is known to enhance survival upon exposure to stress. The present work aimed to examine the genetic variability of rpoS in a selection of Salmonella enterica subspecies environmental isolates with an automated single-strand conformation polymorphism analysis technique. The results indicated that sequence variation does occur and that these changes are mainly located in two areas: at the center and near the end of the coding region. The variability was generally at the single-base level, although one strain (S. arizonae) did demonstrate significant differences in nucleotide sequence.