Growth of bacteria and fungi in parenteral nutrition solutions containing albumin.

The ability of total parenteral nutrition (TPN) solutions containing albumin to support bacterial and fungal growth was studied. The following solutions were tested for microbial growth: (A) thioglycolate broth, (B) solution A with preservatives, (C) albumin 6.25 g in 500 ml 0.9% sodium chloride injections, (D) solution C with preservatives, (E) amino acid and dextrose TPN solution with magnesium sulfate and folic acid, (F) solution E with albumin 6.25 g in 500 ml, (G) amino acid and dextrose TPN solution with calcium gluconate and multivitamins, and (H) solution G with albumin 6.25 g in 500 ml. Each solution was inoculated with 1 X 10(5) bacteria/ml or 1 X 10(3) yeast/ml in 12 serial dilutions using minimum inhibitory concentration (MIC) plates. These were incubated at 37 degrees C for 48 hours, and cultures were visually rated on a scale of 0 (no growth) to 4 (maximal growth). Each culture was repeated for a total of 10 samples. Microbial growth was not affected by the low concentrations of preservatives available from the TPN additives. Undiluted TPN solutions were able to sustain fungal growth only. There was a significant increase in microbial growth in diluted TPN solutions containing albumin for S. aureus, C. albicans, T. glabrata, K. brier, S. marcescans, and E. coli. The presence of vitamins (solution G) impaired the ability of gram-negative bacteria to proliferate, and the addition of albumin (solution H) had no significant effect on the growth characteristics of the organisms in the solution. The presence of albumin had no effect on the growth of S. faecalis or Ps. aeruginosa. The addition of albumin to crystalline amino acid TPN solutions increases the potential of these solutions to support the growth of fungi and bacteria. Hence, it is recommended that albumin be administered separate from amino acid TPN solutions.