Didier M E, Fischer S, Maki D G
Department of Medicine, University of Wisconsin Medical School, University of Wisconsin-Madison, USA.
JPEN J Parenter Enteral Nutr. 1998 Sep-Oct;22(5):291-6. doi: 10.1177/0148607198022005291.
The extraordinary growth properties of most microorganisms in 10% and 20% lipid emulsions has led to the Centers for Disease Control and Prevention recommendation that if lipids are given through an i.v. line, the administration set should be replaced every 24 hours rather than the usual 72-hour interval used for crystalloid solutions, including those used for conventional total parenteral nutrition. For nearly 15 years, parenteral alimentation has been given as a total nutrient admixture (TNA), with the glucose, amino acids, and lipid mixed within the same bag and infused continuously over 24 hours.
We prospectively studied in a representative TNA (17.6% glucose, 5% amino acids, 4% lipid; pH 5.6, osmolality 1778) and in a control solution, 5% dextrose-in-water (D5%/W), the growth properties at 4, 25, and 35 degrees C of three isolates each of Staphylococcus epidermidis, Staphylococcus aureus, Enterobacter cloacae, Klebsiella oxytoca, Serratia marcescens, Acinetobacter calcoaceticus, Stenotrophomonas maltophilia, Pseudomonas aeruginosa, Burkholderia cepacia, Flavobacterium spp, and Candida albicans, and two isolates of Staphylococcus saprophyticus, the species that are most likely to contaminate TNA during preparation or administration and that have been implicated in >95% of all outbreaks and sporadic cases of nosocomial bloodstream infections traced to contaminated parenteral admixtures reported in the world literature.
Growth in TNA at 25 and 35 degrees C occurred with only two species, C. albicans and S. saprophyticus, and only after 24 to 48 hours; D5%/W allowed growth at 25 degrees C of two gram-negative species, S. marcescens and B. cepacia.
We conclude that TNA is a poor growth medium for most nosocomial pathogens and is no better than D5%/W. The need to replace administration sets every 24 hours with TNA should be reconsidered and ideally be studied in a prospective randomized trial.
大多数微生物在10%和20%的脂质乳剂中具有非凡的生长特性，这导致疾病控制与预防中心建议，如果通过静脉输液管给予脂质，给药装置应每24小时更换一次，而不是像用于晶体溶液（包括用于传统全胃肠外营养的溶液）那样通常每72小时更换一次。近15年来，胃肠外营养一直以全营养混合液（TNA）的形式给予，葡萄糖、氨基酸和脂质在同一袋中混合，并在24小时内持续输注。
我们前瞻性地研究了一种代表性的TNA（17.6%葡萄糖、5%氨基酸、4%脂质；pH 5.6，渗透压1778）和一种对照溶液5%葡萄糖水溶液（D5%/W），在4℃、25℃和35℃下表皮葡萄球菌、金黄色葡萄球菌、阴沟肠杆菌、产酸克雷伯菌、粘质沙雷菌、醋酸钙不动杆菌、嗜麦芽窄食单胞菌、铜绿假单胞菌、洋葱伯克霍尔德菌、黄杆菌属和白色念珠菌各三株，以及腐生葡萄球菌两株的生长特性，这些是在制备或给药过程中最有可能污染TNA的菌种，并且在世界文献报道的所有因污染胃肠外混合液导致的医院血流感染暴发和散发病例中，它们占到了95%以上。
仅白色念珠菌和腐生葡萄球菌这两种菌在25℃和35℃的TNA中生长，且仅在24至48小时后生长；D5%/W允许粘质沙雷菌和洋葱伯克霍尔德菌这两种革兰氏阴性菌在25℃下生长。
我们得出结论，TNA对大多数医院病原体而言是一种不良的生长培养基，并不比D5%/W好。每24小时更换TNA给药装置的必要性应重新考虑，理想情况下应在前瞻性随机试验中进行研究。
