实时定量PCR检测外科发热患者静脉血中细菌DNA含量及其与体征、血细胞计数的相关性

Correlations of enterobacteria DNA load in venous blood determined by real-time quantitative polymer- ase chain reaction with vital signs and blood cell count in febrile surgical patients

目的 采用实时定量PCR（RQ-PCR）检测外科发热患者静脉血中肠道DNA，研究其与体征及血细胞计数之间的相关性，并比较不同检测方法对血中细菌阳性检出率的差异。方法 对72份血标本进行常规细菌培养及RQ-PCR定量检测，比较两种检测方法对血中细菌阳性检出率的差异，并计算细菌DNA含量与体温、心率、白细胞计数、中性粒细胞及淋巴细胞百分比之间的相关性。结果 RQ-PCR定量检测细菌DNA阳性率（63.89%）显著高于细菌培养阳性率（9.72%）（F=4.383，P=0.036）。血中细菌DNA含量与体温和心率显著相关（P=0.006，r=0.323；P=0.000，r=0.411），与白细胞计数、中性粒细胞及淋巴细胞百分比无相关性（P=0.438，r=0.093；P=0.825，r=0.027；P=0.451， r=－0.090）；同年龄无相关性（P=0.096，r=0.198）结论 RQ-PCR可用于定量检测外周血中细菌DNA的含量，快速且灵敏度高。血细胞计数不能较好地反映血中细菌的含量，而体温、心率的影响因素较多。

Objective To determine enterobacteria DNA load in venous blood of febrile surgical patients using real-time quantitative polymerase chain reaction （RQ-PCR）, to study the correlations between DNA load and vital signs/blood cell count, and to compare the difference between different detection methods in terms of positive rates. Methods A total of 72 blood samples were obtained for bacterial culture and RQ-PCR. The correlations of enterobacteria DNA load with body temperature, heart rate, while blood cell count, and percentages of leukocyte and lymphocyte were then analyzed. Results The enterobacteria positive rate determined by RQ-PCR （63.89%） was significantly higher than that by bacterial culture （9.72%）（F=4.383, P=0.036）. The DNA load was significantly correlated with both body temperature and heart rate （P=0.006, r=0.323; P=0.000, r=0.411）, but not with white blood cell count, percentages of leukocyte and lymphocyte, and age（P=0.438,r=0.093; P=0.825, r=0.027; P=0.451, r=-0.090; P=0.096, r=0.198）. Conclusions RQ-PCR can quickly determine the enterobacteria DNA load in peripheral blood with high sensitivity. Routine blood cell count may not accurately reflect the enterobacteria DNA load in blood. Body temperature and heart rate may be influenced by various factors.