目的 分析双歧杆菌对肺部感染所致脓毒症患者肠道菌群及相关免疫功能标志物的影响，为其临床应用提供数据支撑。 方法 将143例肺部感染所致脓毒症随机分为两组，其中71例常规治疗者为对照组，72例在常规治疗的基础上加用双歧杆菌者为研究组。分别于治疗前及治疗7 d时评估急性生理和慢性健康（APACHEⅡ）评分与序贯器官功能衰竭（SOFA）评分；并取粪便样本，分析主要肠道菌群乳酸杆菌、双歧杆菌、肠杆菌、肠球菌、大肠埃希菌及梭菌的菌落数量；取外周血，采用流式细胞实验测定T淋巴细胞亚群的水平，采用肠道屏障功能生化指标分析系统检测血清D-乳酸、细菌内毒素水平，采用ELISA实验测定炎性因子降钙素原（PCT）、超敏C反应蛋白（hs-CRP）和白细胞介素6（IL-6）的血浆水平。 结果 治疗前，两组的APACHEⅡ与SOFA评分、肠道菌群数量、肠道功能、T淋巴细胞亚群及炎性因子的水平差异均无统计学意义（P > 0.05）。治疗后，两组的APACHEⅡ与SOFA评分均有明显降低，且研究组APACHEⅡ评分显著低于对照组（P < 0.05）。治疗后，两组的乳酸杆菌、双歧杆菌数量及CD3⁺T%水平均有升高，肠球菌、大肠埃希菌数量，肠道功能评分，D-乳酸、内毒素、TNF-ɑ、IL-6及IL-1β水平均有降低；且研究组乳酸杆菌、双歧杆菌数量及CD3⁺T%水平高于对照组，大肠埃希菌数量、D-乳酸、内毒素、hs-CRP及IL-6水平低于对照组（P < 0.05）。 结论 在肺部感染所致脓毒症的临床治疗中加用双歧杆菌，可从一定程度上改善肠道菌群分布，并缓解炎症带来的肠道屏障功能损伤，对促进患者修复可能有帮助。

Objective To analyze the effects of bifidum on intestinal flora and related immune function markers in patients with sepsis caused by lung infection， and to provide data for supporting clinical application. Methods One hundred and forty-three cases of sepsis caused by lung infection were randomly divided into two groups， including 71 cases of control group （received conventional treatment） and 72 cases of study group （received bifidum in addition to conventional treatment）. Critical illness scores ［Acute Physiological and Chronic health （APACHEⅡ） score and Sequential Organ failure （SOFA） score］ were evaluated before treatment and at 7 days after treatment， respectively. Fecal samples were collected to analyze the colonies of Lactobacillus， bifidum， Enterobacter， enterococcus， Escherichia coli and Clostridium. Peripheral blood was collected and the level of T lymphocyte subpopulation in blood was determined by flow cytometry. The plasma D-lactic acid and bacterial endotoxin levels were detected by intestinal barrier function biochemical index analysis system. The plasma levels of procalcitonin （PCT）， hypersensitive C-reactive protein （hs-CRP） and interleukin-6 （IL-6） were also determined by ELISA. Results Before treatment， there were no significant differences in critical disease score， intestinal flora number， intestinal function， T lymphocyte subsets and inflammatory factors between the two groups （P > 0.05）. After treatment， APACHEⅡ and SOFA scores in both groups were significantly reduced， and APACHEⅡ scores in the study group were significantly lower than those in the control group （P < 0.05）. After treatment， the number of Lactobacillus， bifidum and CD3⁺T% levels in both groups increased， while the number of enterococcus， Escherichia coli， intestinal function score， D-lactic acid， endotoxin， TNF-ɑ， IL-6 and IL-1β levels decreased. The levels of Lactobacillus， bifidum and CD3⁺T% in the study group were higher than those in the control group， while the levels of Escherichia coli， D-lactic acid， endotoxin， hs-CRP and IL-6 in the study group were lower than those in the control group （P < 0.05）. Conclusion Adding bifidum in the clinical treatment of sepsis caused by lung infection can improve the distribution of intestinal flora to a certain extent and alleviate the damage of intestinal barrier function caused by inflammation， which may be helpful to promote the repair of patients.