Detection of Salmonella spp. carriers using invA gene amplification in equine feces

The Polymerase Chain Reaction (PCR) and conventional cultivation methods were carried out to detect 1) the invA gene of Salmonella spp. in horses and mules' feces, 2) the rapidity and sensitivity of PCR technique in compare with microbiological culture and 3) detection of the carrier rate on the basis of sex, age and animal species for Salmonella spp. in equine. One hundred fecal samples were taken from equine family included 76 horses (67 stallions and 9 mares) and 24 mules (16 stallions and 8 mares) from different regions of Urmia, Iran, in 2009. The frequency of age distribution up to 4, 6, 8, 10, and >10 years old were 7, 24, 37, 19, 13 animals, respectively. Fecal samples were used for Salmonella isolation by current culturing techniques and biochemical tests. Samples were enriched in enrichment broth and DNA were extracted and amplified by PCR method using specific primers of Salmonella invasion gene (invA). PCR products were visualized using 1.2% Agarose Gel Electrophoresis. The bacterial culturing results were negative for all feces, whilst PCR and electrophoresis confirmed the presence of Salmonella in three feces (3%) in which they were stallion, 6 years old and horses. These result; indicate that the PCR method is highly sensitive and rapid for Salmonella detection in fecal samples than other current methods.