Competitive inhibition bacteria of bovine origin against Salmonella spp.

Abstract

108 fecal samples were obtained from calves, dairy and beef cows. Salmonella spp. was isolated from 9.25% of samples. Of 1097 bacterial isolates from cattle feces screened, 30 demonstrated anti- S. Typhimurium DT104 activity in vitro. Isolates included 22 Escherichia coli, 6 Bacillus circulans, 1 Serratia fonticola, and 1 Enterobacter cloacae. Identification by pulsed-field gel electrophoresis revealed 19 distinguishable profiles among the 24 gram-negative isolates. Competitive inhibition isolates did not significantly reduce S. Typhimurium DT104 during 21 days of storage at 37°C in cattle feces. B. circulans (10 5 CFU/g inoculum) significantly reduced S. Newport on days 3 and 5 and at day 21 with a 10 8 CFU/g inoculum at 37°C. At 21°C, significant reductions of S. Typhimurium DT104 occurred due to 10 8 CFU/g of gram-negative competitive inhibition bacteria and 10 5 CFU/g of B. circulans at day five only. No significant reductions were seen with S. Newport at 21°C.