Unique temperature-sensitive nutritional requirements of bacteremic Escherichia coli isolates.

Of 50 strains of Escherichia coli isolated from blood cultures of bacteremic patients, 14 (28%) were unable to grow on minimal medium at 42 degrees C, compared to only 2 of 50 nonbacteremic strains. In 7 of the 14 bacteremic strains, growth at 42 degrees C was restored by adding nicotinic acid. These unique temperature-sensitive auxotrophic patterns warrant evaluation as a marker correlating with clinical pathogenicity in E. coli.