Growth of toxigenic Escherichia coli in oral rehydration solutions

The ability of three strains of toxigenic Escherichia coli to grow in glucose-electrolyte oral rehydration solution (ORS) used for the treatment of dehydration due to diarrhea was studied. The purpose was to determine the potential risk that such home-based therapy might pose for transmission of infection if the ORS were contaminated with potential pathogens. Inocula of 10(5) unwashed organisms from broth culture were rapidly killed in ORS made with chlorinated tap water and increased by 1.5-2 log10 in ORS in triple-distilled laboratory water. When media constituents were first removed by washing, one strain failed to grow in ORS-distilled water, but multiplied to a level of 10(6) organisms/ml in ORS in water obtained from a rural village in the highlands of Guatemala. Multiplication of organisms in ORS depends on the presence of a nitrogen source. These limited data support current guidelines for preparation and use of ORS in the field employing available drinking water, as bacterial growth is restricted by the nitrogen content of the water.