title: Growth of microorganisms in total parenteral nutrition solutions without lipid.
abstract: BACKGROUND
  To identify the microorganisms that can grow rapidly in total parenteral nutrition (TPN) solutions, we investigated the growth of the major causes of catheter-related blood stream infection (Staphylococcus aureus, Serratia marcescens, Bacillus cereus, and Candida albicans) in TPN solutions without lipid.
  
  
  METHODS
  Experiment 1: A commercial TPN solution without lipid containing multivitamins (pH5.6) was used. A specific number of each test microorganism was added to each 10 mL of the TPN solution and incubated at room temperature. An aliquot of test solution was sampled and inoculated to SCD agar plates at 0, 24, and 48 hrs after the addition of the microorganisms. The number of microorganisms was counted as colony forming units. Experiment 2: The other 2 commercial TPN solutions without lipid (pH5.5) were supplemented with multivitamins. The pH values of the solutions were adjusted to about 6.0, 6.5, or 7.0 using 0.5 mol/L NaOH. The addition of microorganisms, incubation, and counting were performed in the same manner.
  
  
  RESULTS
  Experiment 1: S. aureus, S. marcescens, and B. cereus did not increase in the TPN solution without lipid containing multivitamins (pH5.6), but C. albicans increased rapidly. Experiment 2: The 3 bacterial species did not increase even at pH6.0, but increased at pH6.5 and increased rapidly at pH7.0 in both TPN solutions. C. albicans increased similarly at any pH.
  
  
  CONCLUSIONS
  These results suggest that bacterial species cannot grow in TPN solutions without lipid due to the acidity (pH5.6 or lower), but Candida species can grow regardless of the acidity.
authors.affiliation: Preclinical Assessment Department, Otsuka Pharmaceutical Factory, Inc., 115 Tateiwa, Naruto, Tokushima 772-8601, Japan. kuwahat2@otsukakj.co.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Kuwahara
authors.forename: Shinya
authors.initials: S
authors.lastname: Kaneda
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Shimono
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D001409:Bacillus cereus / Q000187:drug effects / Q000254:growth & development; D001419:Bacteria / Q000254:growth & development*; D001431:Bacteriological Techniques; D002176:Candida albicans / Q000187:drug effects / Q000254:growth & development; D004041:Dietary Fats / Q000494:pharmacology; D004340:Drug Contamination; D006863:Hydrogen-Ion Concentration; D008055:Lipids / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D010289:Parenteral Nutrition, Total / Q000592:standards; D012706:Serratia marcescens / Q000187:drug effects / Q000254:growth & development; D012996:Solutions / Q000008:administration & dosage / Q000494:pharmacology / Q000592:standards; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development
chemical_list: D004041:Dietary Fats; D008055:Lipids; D012996:Solutions