Growth of bacteria in intravenous fluids under stimulated actual-use conditions

The growth of microorganisms in nonnutritive intravenous solutions under simulated actual-use conditions was studied. Small quantities of Pseudomonas aeruginosa, Staphylococcus aureus, and Klebsiella pneumoniae (final concentration 200-400 cells/ml) were injected into 500-ml containers (glass bottles and plastic bags) of 5% dextrose injection, 0.9% sodium chloride injection, and 5% dextrose and 0.9% sodium chloride injection. Additives (ampicillin, vitamin K, lidocaine, and vitamin B complex) were included in some i.v. solutions. Administration sets were attached to the i.v. containers, and the solutions were run into collection bottles; samples were withdrawn at 0, 1, 2, 3, 4, 5, 6, and 8 hours after contamination and plated for viable counts. Staph. aureus and K. pneumoniae remained viable in 5% dextrose injection and in 0.9% sodium chloride injection, but the numbers of these bacteria did not increase. The number of Ps. aeruginosa declined in all three solutions. In 5% dextrose and 0.9% sodium chloride injection, the number of K. pneumoniae declined but Staph. aureus maintained viability. The type of container and the drug additives had no effect on microbial growth, except that ampicillin was bactericidal to Staph. aureus. Low-level contamination of these bacteria in nonnutritive i.v. solutions under actual-use conditions does not result in large numbers of organisms within the time frame in which most solutions are administered.