Comparative studies of diagnostic bacteriological methods for the recovery of Salmonella from faecal samples from flocks of layers.

Several conventional culture procedures were compared for the recovery of Salmonella from faecal samples of layer flocks. The cultural media employed consisted of Rappaport-Vassiliadis and tetrathionate broth for selective enrichment and three different plating media (Brilliant Green, Xylose-Lysine-Desoxycholate and modified semisolid Rappaport-Vassiliadis medium). The initial enrichment and plating procedures were repeated in a four-stage secondary enrichment. Selective enrichment in Rappaport-Vassiliadis or tetrathionate broth followed by plating on modified semisolid Rappaport-Vassiliadis medium (selective motility enrichment) resulted in a significantly higher isolation rate for Salmonella from faecal samples of layers compared to Brilliant Green and Xylose-Lysine-Desoxycholate medium. The selective enrichment yielded additional Salmonella isolates up to the second stage. Further enrichment did not increase the isolation rate.