Austin P D, Hand K S, Elia M
Faculty of Medicine, University of Southampton, Southampton, UK; Southampton Pharmacy Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, UK; Pharmacy Department, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
Southampton Pharmacy Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, UK; Faculty of Health Sciences, University of Southampton, Southampton, UK.
J Hosp Infect. 2016 Dec;94(4):307-319. doi: 10.1016/j.jhin.2016.08.026. Epub 2016 Sep 7.
As lipid in parenteral nutrition (PN) purportedly enhances microbial growth, recommendations limit infusion of lipid PN (or lipid emulsion) from a single container to 24h (48h for lipid-free PN). However, the associated evidence base is ambiguous.
To examine factors affecting microbial growth in PN.
A systematic review with meta-analyses examined effects of nutrients on microbial growth in PN infusates over a 48-h period using the growth ratio {GR=log[colony-forming units (cfu)/mL at 48h/cfu/mL at time zero]}.
Factors influencing GR in PN included glucose, microbial species, temperature, osmolarity, presence of vitamins, trace elements and lipid, and amino acid profile. Using unmatched datasets (N=306), a general linear model found that lipid inclusion in PN represented 3.3% of the variability, which was less than that due to glucose concentration (5.8%), microbial species (35.3%) and microbe-infusate interaction (4.4%). Using matched datasets (N=38 pairs), lipid inclusion in PN represented 5.4% of the variability (P=0.076), which was less than that due to glucose concentration (8.5%; P=0.025), microbial species (75.5%; P<0.001) and microbe-infusate interaction (13.3%; P=0.382). Using meta-analyses of matched datasets, the presence of lipid in PN at fixed glucose concentrations did not significantly increase GR of Candida albicans, Escherichia coli or Staphylococcus epidermidis (P=0.352, P=0.025 and P=0.494, respectively; overall P=0.175).
Lipid inclusion in PN is only one of several factors that may influence microbial growth in PN. Any recommendations about the duration of PN infusion from a single container should account for all these factors, and should be weighted according to microbial species likely to contaminate PN.
由于肠外营养（PN）中的脂质据称会促进微生物生长，相关建议将单个容器中脂质PN（或脂质乳剂）的输注时间限制为24小时（无脂PN为48小时）。然而，相关的证据基础并不明确。
研究影响PN中微生物生长的因素。
一项系统评价及荟萃分析，使用生长率{GR = log[48小时时的菌落形成单位（cfu）/毫升÷零时的cfu/毫升]}，考察了营养素对PN输注液中微生物在48小时内生长的影响。
影响PN中GR的因素包括葡萄糖、微生物种类、温度、渗透压、维生素、微量元素和脂质的存在以及氨基酸谱。使用未匹配数据集（N = 306），一个通用线性模型发现PN中脂质的加入占变异性的3.3%，低于葡萄糖浓度（5.8%）、微生物种类（35.3%）和微生物 - 输注液相互作用（4.4%）所致的变异性。使用匹配数据集（N = 38对），PN中脂质的加入占变异性的5.4%（P = 0.076），低于葡萄糖浓度（8.5%；P = 0.025）、微生物种类（75.5%；P < 0.001）和微生物 - 输注液相互作用（13.3%；P = 0.382）所致的变异性。使用匹配数据集的荟萃分析，在固定葡萄糖浓度下PN中脂质的存在并未显著增加白色念珠菌、大肠杆菌或表皮葡萄球菌的GR（分别为P = 0.352、P = 0.025和P = 0.494；总体P = 0.175）。
PN中脂质的加入只是可能影响PN中微生物生长的几个因素之一。关于单个容器中PN输注持续时间的任何建议都应考虑所有这些因素，并应根据可能污染PN的微生物种类进行权衡。
