Table 2.

Probiotic bacteria do not interfere with Salmonella typhimurium–HT-29 cell association

	Plate dilution method	Biofluorescence method
Sample	Cell-associated S. typhimurium (log CFU/ml)*	% of cell-associated S. typhimurium†
S. typhimurium	3·24E + 05 ± 1·25E + 05	100
B. infantis + S. typhimurium	3·25E + 05 ± 8·85E + 04	90·02 ± 13·75
L. salivarius + S. typhimurium	3·61E + 05 ± 7·23E + 04	112·04 ± 10·85

Probiotic interference with pathogen binding was evaluated by quantifying the numbers of S. typhimurium associated with HT-29 cells in the presence or absence of probiotic pretreatment. Data represent the mean ± standard error of three independent experiments.

^*Intestinal epithelial cell (IEC)-associated S. typhimurium were quantified by colony-forming units (CFU) counts of diluted cell lysates on tryptic soy agar (TSA) and results are expressed as log CFU/ml.

^†IEC-associated S. typhimurium were quantified by in vivo imaging fluorescence using a standard curve of serial dilutions of SYTO 9-labelled S. typhimurium relative to fluorescent intensity. Results are expressed as per cent HT-29 cell-associated S. typhimurium.

B. infantis, Bifidobacterium infantis; L. salivarius, Lactobacillus salivarius.