Department of Infectious Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China.
Chin Med J (Engl). 2011 Dec;124(23):4002-6.
Blood culture contamination is a significant adverse event. The aim of this project was to evaluate the efficacy of a strict blood collection procedure in reducing the blood culture contamination rate.
A prospectively controlled study was performed in two different medical areas in Peking Union Medical College Hospital (PUMCH) for 16 months (from May 2006 to September 2007). In test group, a strict blood collection procedure was carried out by trained nurses with the veinpuncture sites were scrupulously disinfected with 2.5% tincture of iodine plus 70% alcohol. In control group, commonly used procedure in PUMCH was performed with 0.45% chlorhexidine acetate plus 0.2% iodine. Blood culture positive results for 4 target organisms (Coagulase-negative staphylococci, Propionibacterium acnes, Corynebacterium species and Bacillus species) were further assessed by physicians from infectious department to determine whether a sample was true positive (pathogen) or false positive (contamination).
Total 9321 blood culture collections were analyzed. The blood culture contamination rate in test group was significantly lower than that in control group (5/3177 (0.16%) vs. 77/6144 (1.25%); χ(2) = 13.382, P < 0.001). The most common contaminant was Coagulase-negative staphylococcus (76.83%). The average cultural time during which contaminated samples became positive was longer than that for true pathogen samples (42.0 hours vs. 13.9 hours, P = 0.041).
Using a strict blood collection procedure can significantly reduce blood culture contamination rate.
血培养污染是一种严重的不良事件。本项目旨在评估严格的血采集程序在降低血培养污染率方面的效果。
在北京协和医院（PUMCH）的两个不同医疗区进行了一项前瞻性对照研究，时间为 16 个月（2006 年 5 月至 2007 年 9 月）。在实验组中，经过培训的护士采用严格的血采集程序，对静脉穿刺部位进行仔细消毒，使用 2.5%碘酒加 70%酒精。在对照组中，采用 PUMCH 常用的程序，使用 0.45%醋酸洗必泰加 0.2%碘酒。由感染科医生对 4 种目标菌（凝固酶阴性葡萄球菌、痤疮丙酸杆菌、棒状杆菌属和芽孢杆菌属）的血培养阳性结果进行进一步评估，以确定样本是真正的阳性（病原体）还是假阳性（污染）。
共分析了 9321 份血培养标本。实验组的血培养污染率明显低于对照组（5/3177（0.16%）vs. 77/6144（1.25%）；χ(2) = 13.382，P < 0.001）。最常见的污染菌是凝固酶阴性葡萄球菌（76.83%）。污染样本变为阳性的平均培养时间长于真正病原体样本（42.0 小时 vs. 13.9 小时，P = 0.041）。
采用严格的血采集程序可显著降低血培养污染率。
