title: Growth of microorganisms in total parenteral nutrition solutions containing 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 containing lipid.
  
  
  METHODS
  The pH value of a TPN solution containing lipid (pH 6.0, containing 20 ppm of NaHSO(3)) was adjusted by the addition of HCl to 5.7, 5.4, or 4.9. The pH value of another TPN solution (pH5.5, containing 400 ppm of NaHSO(3)) was adjusted by the addition of NaOH to 5.9, 6.3, or 6.8. A specific number of each microorganism was added to 10 mL of each test solution and incubated at room temperature. The number of microorganisms was counted as colony forming units at 0, 24, and 48 hrs later.
  
  
  RESULTS
  C albicans increased similarly at any pH values in the TPN solution. The bacterial species also increased rapidly at pH6.0 in the solution containing 20 ppm of NaHSO(3), but growth was suppressed as the pH value was reduced, with growth halted at pH4.9. However, these bacterial species did not increase, even at pH5.9, in the other solution containing 400 ppm of NaHSO(3).
  
  
  CONCLUSIONS
  These results suggest that Candida species can grow rapidly in almost all TPN solutions regardless of the acidity, lipid, and NaHSO(3); also, some bacterial species may grow in TPN solutions containing lipid unless the pH value is 5.0 or less. Therefore, each TPN solution should be examined whether or not the bacterial species can proliferate.
authors.affiliation: Preclinical Assessment Department, Otsuka Pharmaceutical Factory, Inc., Tokushima, Japan. kuwahat2@otsukakj.co.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Kuwahara
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Shimono
authors.forename: Shinya
authors.initials: S
authors.lastname: Kaneda
authors.forename: Takumi
authors.initials: T
authors.lastname: Tamura
authors.forename: Masao
authors.initials: M
authors.lastname: Ichihara
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Nakashima
mesh_terms: D001409:Bacillus cereus / Q000187:drug effects / Q000254:growth & development; D002175:Candida / Q000187:drug effects / Q000254:growth & development; D006863:Hydrogen-Ion Concentration; D010289:Parenteral Nutrition, Total; D012706:Serratia marcescens / Q000187:drug effects / Q000254:growth & development; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development; D013447:Sulfites / Q000494:pharmacology
chemical_list: D013447:Sulfites; C042345:hydrogen sulfite