Department of Laboratory Medicine, Gyeongsang Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Korea.
Ann Lab Med. 2013 Nov;33(6):406-9. doi: 10.3343/alm.2013.33.6.406. Epub 2013 Oct 17.
Delayed entry of blood culture bottles is inevitable when microbiological laboratories do not operate for 24 hr. There are few studies reported for prestorage of these bottles. The growth dynamics of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were investigated with respect to various preincubation conditions.
Fifteen or 150 colony-forming units (CFU) of bacteria were inoculated into standard aerobic or anaerobic blood culture bottles. Bottles were preincubated at 25℃ or 37℃ for 0, 2, 4, 8, 12, 24, or 48 hr. The time to detection (TTD) then was monitored using the BacT/Alert 3D system (bioMerieux Inc., USA).
Significant difference in TTD was observed following preincubation for 8 hr at 25℃ vs. 4 hr at 37℃ for S. aureus, 4 hr at 25℃ vs. 4 hr at 37℃ for E. coli, 12 hr at 25℃ vs. 4 hr at 37℃ for P. aeruginosa, compared to no preincubation (P<0.005). TTD values did not vary significantly with bacterial CFU or with aerobic or anaerobic bottle type. The BacT/Alert 3D system returned false negatives following preincubation of P. aeruginosa for 48 hr at 25℃ or 24 hr at 37℃.
TTD was mainly affected by preincubation temperature and duration rather than by input CFU quantity or bottle type for the 3 experimental bacteria.
当微生物实验室不 24 小时运行时，血液培养瓶的延迟进入是不可避免的。目前报道的关于这些瓶子的预储存的研究很少。研究了金黄色葡萄球菌、大肠杆菌和铜绿假单胞菌在不同预孵育条件下的生长动态。
将 15 或 150 个细菌菌落形成单位（CFU）接种到标准需氧或厌氧血培养瓶中。将瓶在 25℃或 37℃下预孵育 0、2、4、8、12、24 或 48 小时。然后使用 BacT/Alert 3D 系统（bioMerieux Inc.，美国）监测检测时间（TTD）。
在 25℃下预孵育 8 小时与在 37℃下预孵育 4 小时相比，金黄色葡萄球菌的 TTD 存在显著差异，在 25℃下预孵育 4 小时与在 37℃下预孵育 4 小时相比，大肠杆菌的 TTD 存在显著差异，在 25℃下预孵育 12 小时与在 37℃下预孵育 4 小时相比，铜绿假单胞菌的 TTD 存在显著差异，与无预孵育相比（P<0.005）。TTD 值与细菌 CFU 或需氧或厌氧瓶类型无显著差异。在 25℃下预孵育 48 小时或在 37℃下预孵育 24 小时后，BacT/Alert 3D 系统对铜绿假单胞菌的检测结果为假阴性。
对于 3 种实验菌，TTD 主要受预孵育温度和时间的影响，而不受输入 CFU 数量或瓶类型的影响。
