The aim of this study was to compare different DNA-extraction methods and selective enrichment broths for their effectiveness to detect Salmonella Typhimurium in artificially inoculated swine feces samples (100 CFU/g) by polymerase chain reaction. After enrichment in Rappaport-Vassiliadis, selenite cystine or Müller-Kauffmann tetrathionate, aliquots were used for DNA extraction by three different methods: boiling-centrifugation, phenol-chloroform and salting-out. Aliquots of extracted DNA were then used as template in PCR. The selective enrichment broths had no effect on the efficiency of PCR when boiling-centrifugation and salting-out were used. On the other hand, phenol-chloroform was superior (P<0.05) when combined to Rappaport-Vassiliadis. Considering cost and efficiency parameters, we encourage the use of Müller-Kauffmann tetrathionate broth in combination with boiling-centrifugation DNA-extraction procedure.
diagnosis; DNA; feces; PCR; Salmonella Typhimurium