Comparison of Salmonella typhimurium and Selected Facultative Chicken Cecal Bacteria Survivability after Specific Amino Acid-Limited Batch Growth

Abstract

The objective of this in vitro experimentation was to compare the survivability of Salmonella typhimurium strains and selected facultative chicken cecal bacteria after specific amino acid-limited growth on either serine, threonine, arginine, or aspartate. Survivability of Salmonella typhimurium and chicken cecal bacteria was estimated by measuring the rate of decrease of viable cell numbers and calculating the average time for 50% of the cells to become nonviable (50% survival time, ST50). Two S. typhimurium strains, LT2 and a primary poultry isolate (NO/NA), and three selected facultative chicken cecal bacteria, Citrobacter freundii, Escherichia coli and Escherichia fergusonii, were grown aerobically at 37°C to stationary phase on carbon-limited or nitrogen-limited minimal media. All organisms remained viable longer (P < 0.05) on serine media than on any of the other media tested. When serine was used as a nitrogen source in minimal media the ST50 of C. freundii and E. fergusonii were significantly longer than those of the two S. typhimurium strains. It appears that when media are limited in the same nutrient, the ability to sustain viability varies among facultative bacteria derived from the chicken cecum.