目的:分析重症加强治疗病房(ICU)血流感染脓毒症患者的病原菌特征以及混合血流感染的危险因素和预后。方法回顾性分析2012年10月12日至2014年12月1日广东省人民医院6个ICU中年龄≥18岁且血培养阳性脓毒症患者的临床资料,根据分离出病原菌的数量将患者分为混合感染组和单一感染组。比较两组患者临床资料及病原菌分布情况,采用多因素logistic回归分析筛选混合血流感染的危险因素,采用Kaplan-Meier生存曲线分析患者血培养阳性后90 d存活率。结果共纳入299例患者,分离出病原菌450株,其中革兰阳性球菌246株(占54.67%),革兰阴性杆菌167株(占37.11%),真菌37株(占8.22%)。混合血流感染91例,单一血流感染208例。与单一感染组相比,混合感染组患者年龄更大(岁:73.19±18.02比60.83±18.06,t=-5.447,P=0.000);有脑血管疾病〔39.56%(36/91)比17.79%(37/208),χ2=16.261,P=0.000〕或慢性肾功能不全〔15.38%(14/91)比7.21%(15/208),χ2=4.828,P=0.028〕基础疾病的比例更高;最近90 d内住院且住院时间≥2 d的比例更高〔73.63%(67/91)比61.54%(128/208),χ2=4.078,P=0.043〕;进行机械通气时间〔d:4(0,17)比1(0,6),U=7673.000,P=0.006〕和血培养前住院时间〔d:21(7,40)比9(3,17),U=6441.500,P=0.006〕更长;入院前30 d内静脉使用抗菌药物的比例更高〔84.62%(77/91)比66.83%(139/208),χ2=9.989,P=0.002〕。多因素logistic回归分析显示:高龄〔优势比(OR)=1.032,95%可信区间(95%CI)=1.015~1.050,P=0.000〕、患脑血管疾病(OR=2.247,95%CI=1.234~4.090,P=0.008)、机械通气时间长(OR=1.041,95%CI=1.014~1.069,P=0.003)和最近90 d内住院且住院时间≥2 d(OR=1.968,95%CI=1.079~3.592,P=0.027)是混合血流感染的独立危险因素。与单一感染组相比,混合感染组ICU住院时间〔d:46(22,77)比13(7,22),U=3148.000,P=0.000〕和总住院时间〔d:81(47,118)比28(17,46),U=3620.000,P=0.000〕明显延长,ICU病死率〔65.93%(60/91)比43.75%(91/208),χ2=12.463, P=0.000〕和住院病死率〔68.13%(62/91)比45.67%(95/208),χ2=12.804,P=0.000〕明显升高。Kaplan-Meier生存曲线分析显示,混合感染组90 d累积存活率较单一感染组显著降低(χ2=8.513,P=0.004)。结论 ICU血流感染病原菌以革兰阳性球菌为主。混合血流感染的独立危险因素为高龄、患脑血管疾病、机械通气时间长和90 d内住院史。混合血流感染可延长患者住院时间,增加病死率。
ObjectiveTo investigate the clinical characteristics and pathogenic microorganisms in culture-positive sepsis, to identify its risk factors, and evaluate the prognosis on polymicrobial infection in intensive care unit (ICU).Methods A descriptive retrospective study was conducted. Clinical data of patients aged≥ 18 years, diagnosed as culture-positive sepsis, and admitted to six ICUs of Guangdong General Hospital from October 12th, 2012 to December 1st, 2014 were enrolled. Based on the number of isolated pathogens, patients were divided into polymicrobial infection group (≥two pathogens) and monomicrobial infection group (one pathogen) to investigate the clinical characteristics of patients with culture-positive sepsis and the causative pathogens. Multiple logistic regression was conducted to identify the risk factors for polymicrobial infection. Kaplan-Meier curve was plotted to analyze a 90-day survival rate from the onset of positive blood culture.Results 299 patients with positive blood culture were enrolled. A total of 450 strains of pathogens were isolated including 246 gram-positive cocci (54.67%), 167 gram-negative bacilli (37.11%) and 37 fungi (8.22%). Ninety-one patients had polymicrobial infection, and 208 with monomicrobial infection. Compared with monomicrobial infection group, patients suffering from polymicrobial infection had more advanced age (years: 73.19±18.02 vs. 60.83±18.06,t = -5.447,P = 0.000), also with higher incidence of cerebrovascular diseases [39.56% (36/91) vs. 17.79% (37/208),χ2 = 16.261,P = 0.000] or chronic renal insufficiency [15.38% (14/91) vs. 7.21% (15/208),χ2 = 4.828,P = 0.028], higher incidence of recent hospital stay (≥2 days) within 90 days [73.63% (67/91) vs. 61.54% (128/208),χ2 = 4.078,P = 0.043], longer mechanical ventilation duration [days: 4 (0, 17) vs. 1 (0, 6),U = 7 673.000,P = 0.006], longer length of hospital stay before blood was drawn for culture [days: 21 (7, 40) vs. 9 (3, 17),U = 6 441.500,P = 0.006], and higher incidence of pre-admission intravenous use of antibiotics [84.62% (77/91) vs. 66.83% (139/208),χ2 = 9.989,P = 0.002]. Multiple logistic regression analysis showed that advanced age [odd ratio (OR) = 1.032, 95% confidential interval (95%CI) = 1.015-1.050,P = 0.000], cerebrovascular diseases (OR = 2.247, 95%CI = 1.234-4.090,P = 0.008), prolonged mechanical ventilation (OR =1.041, 95%CI = 1.014-1.069,P = 0.003), and recent hospital stay (≥2 days) within 90 days (OR = 1.968, 95%CI =1.079-3.592,P = 0.027) were the independent risk factors for polymicrobial infection. In the polymicrobial infection group, the length of ICU stay [days: 46 (22, 77) vs. 13 (7, 22),U = 3 148.000,P = 0.000] and hospital stay [days:81 (47, 118) vs. 28 (17, 46),U = 3 620.000,P = 0.000] were significantly longer, and the ICU mortality [65.93%(60/91) vs. 43.75% (91/208),χ2 = 12.463,P = 0.000] and hospital mortality [68.13% (62/91) vs. 45.67% (95/208),χ2 = 12.804,P = 0.000] were significantly higher, and on the other hand the 90-day survival rate was significantly lower than that in the monomicrobial infection group (χ2 = 8.513,P = 0.004).Conclusions The most common pathogen of ICU sepsis is gram-positive cocci. Independent risk factors for polymicrobial infections were found to be advanced age, occurrence of cerebrovascular disease, prolonged mechanical ventilation, and recent hospitalization. Polymicrobial infection is associated with longer length of ICU and hospital stay, as well as higher mortality.