The presumptive identification of Salmonella spp. isolates, obtained
from 7 samples, was evaluated through the amplification of
the gene located on the pathogenicity island 1 of bacteria belonging
to the genus Salmonella. This gene, invA, encodes proteins of the
type III secretion system described as essential for the invasion of
epithelial cells by Salmonella. The PCR amplifications were performed
with primers 139f 50-GTGAAATTATCGCCACGTTCGGGCAA-
30 and 141r 50-TCATCGCACCGTCAAAGGAACC-30 (Rahn et al., 1992).
Thermal cycling started with an initial denaturation step of 95 C
for 1 min, followed by 38 cycles of 30 s at 95 C, 30 s at 64 C, 30 s at
72 C and a final extension of 4 min at 72 C. The amplicon
generated has 285 bp (Malorny et al., 2003).