[Evaluation of selective culture media for the isolation of Salmonella from poultry]

Abstract

Rambach agar, xylose-lysine-deoxycholate agar (XLD) with different concentrations of Tergitol 4 or 7 ethyl-2 methyl-4 undecanol hydrogen sulphate, sodium salt (XLDT4), Salmonella-Shigella agar (SS) and bismuth sulfite agar according to Wilson-Blair (BS) were evaluated using Salmonella spp. serovars and other bacterial species from the intestinal flora of poultry. Growth of the most common Salmonella serovars isolated from chickens in our country were evaluated using a viable counting technique on the different selective media and these results were compared with those obtained on Columbia base (ABC) agar plus 7% bovine blood (Table 1). Samples from Salmonella experimentally inoculated chickens were also examined. Results showed that Rambach, SS and XLD or XLDT4 were all satisfactory for isolation of Salmonella. Bismuth Sulfite agar was too inhibitory for bacteria important in veterinary practice. The characteristic colonies of Salmonella and other common fecal contaminant bacteria growing on SS, Rambach, XLDT4 and SB are shown in Table 2. Addition of tergitol or novobiocin to XLD agar did not completely inhibit the growth of all Proteus spp. strains examined. None of the Proteus spp. strains able to multiply on SS, XLD or XLDT4 agar grew on the commercial Rambach agar. Several different contaminant bacterial species produced Salmonella-like colonies on Rambach, SS, XLD and XLDT4 agars. Because these contaminant bacterial species are different it is advisable to improve the diagnosis by culturing samples on SS, XLD or XLDT4 agar and also simultaneously on Rambach agar.