Mathus-Vliegen Elisabeth M H, Bredius Marjan W J, Binnekade Jan M
Department of Gastroenterology and Hepatology, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
JPEN J Parenter Enteral Nutr. 2006 Nov-Dec;30(6):519-25. doi: 10.1177/0148607106030006519.
Contamination of enteral feedings is an often overlooked source for bacterial infection in the intensive care unit. A new 1-L enteral feeding system with minimal chances of touching critical areas (Nutrison Pack) was compared with routinely used 0.5-L glass bottle systems.
Patients admitted to intensive care were randomized to Pack or glass bottle feeding systems. Cultures were taken from the delivery sets 5 times during the day and from feeding containers and different sites of the system after 24 hours.
Bacteria were present in 3 of 112 glass bottles and in 2 of 95 Pack bags. True bacterial contamination (defined as >10(2) colony-forming units/mL, with same bacteria also present in the delivery set) was found in none of the Packs with a 12-h (69 Packs) or a 24-h (26 Packs) hanging time and in only 1 of the glass bottles with a hanging time of 24 hours, which exceeded the advised hanging time of 8 hours. In contrast, the contamination rate of delivery sets was 48%, with increasing bacterial counts over the day and 4 subsequent days. Bacteria mainly belonged to the group of potentially pathogenic bacteria (Enterobacteriaceae and Pseudomonaceae). They likely originated from throat, lungs, and stomach and grew into and along feeding tubes upwards until they reached the delivery set.
Prolonged hanging times of Pack bags were safe with respect to bacterial contamination. However, the bacterial safety of enteral feedings is more likely to be endangered by the endogenous route of contamination rather than exogenous contamination, as high bacterial counts were found in feeding tubes and delivery sets as a result of retrograde growth.
肠内营养制剂污染是重症监护病房中一个常被忽视的细菌感染源。将一种新的、接触关键部位几率极小的1升肠内营养系统（纽迪希亚营养袋）与常规使用的0.5升玻璃瓶系统进行比较。
入住重症监护病房的患者被随机分配至使用营养袋或玻璃瓶喂养系统。在一天内从输送装置采集5次培养样本，并在24小时后从喂养容器及系统的不同部位采集样本。
112个玻璃瓶中有3个检测出细菌，95个营养袋中有2个检测出细菌。在悬挂时间为12小时（69个营养袋）或24小时（26个营养袋）的营养袋中均未发现真正的细菌污染（定义为>10²菌落形成单位/毫升，且输送装置中也存在相同细菌），而在悬挂时间为24小时（超过建议的8小时悬挂时间）的玻璃瓶中仅1个检测出细菌。相比之下，输送装置的污染率为48%，且在当天及随后4天细菌数量不断增加。细菌主要属于潜在致病菌组（肠杆菌科和假单胞菌科）。它们可能源自咽喉、肺部和胃部，并沿喂养管向上生长直至到达输送装置。
就细菌污染而言，营养袋延长悬挂时间是安全的。然而，肠内营养的细菌安全性更可能受到内源性污染途径而非外源性污染的威胁，因为逆行生长导致喂养管和输送装置中细菌数量很高。
