The effects of iron and temperature on the growth of Listeria monocytogenes in cell-free media.

The effects of variable iron and temperature on the growth of L. monocytogenes in vitro was investigated in cell-free tissue culture Medium 199. Two temperatures, 37 degrees and 42 degrees C, and varying concentrations of iron (Fe+3) derived from ferric ammonium citrate, 40--130 microgram/ml, were selected for the study. Under these conditions, L. monocytogenes exhibited better growth at 37 degrees C than at 42 degrees C. Dose-effect was demonstrated at every succeeding higher Fe+3 concentration except 130 microgram/ml which was inhibitory. The implications of these results for tissue culture models and host-parasite relationship, are discussed.