血培养临床医生应该知道什么

血培养: 临床医生应该知道的,北京协和医院杜斌,Conflicts of Interest,Speaker fee or consultation fee from the following pharmaceutical companiesGSKEli lillyPfizerSanofi-AventisXian JasenMSDBayerWyeth,危重病患者的全身性感染,Brun-Buisson C, Doyon F, Carlet J, et al. Incidence, risk factors, and outcome of severe sepsis and septic shock in adults: a multicenter prospective study in intensive care units; French ICU Group for Severe Sepsis. JAMA 1995; 274: 968-974,血行性感染: 概述,在医院获得性感染中所占比例逐渐增加 200,000例血行性感染/年病死率40 50%,血行性感染的致病菌,Michael B. Edmond, Sarah E. Wallace, Donna K. McClish, et al. Nosocomial Bloodstream Infections in United States Hospitals: A Three-Year Analysis. Clin Infect Dis 1999; 29: 239-44.Lyytikainen O, Lumio J, Sarkkinen H, et al. Nosocomial Bloodstream Infections in Finnish Hospitals during 19992000. Clin Infect Dis 2002; 35: e14-9,血培养: 临床意义,Perez A, Herranz M, Segura M, et al. Epidemiologic impact of blood culture practices and antibiotic consumption on pneumococcal bacteraemia in children. Eur J ClinMicrobiol Infect Dis 2008; 27: 717-724,Navarre vs. Majorca (2000 2004)Occult bacteraemiaRR 11.8 (4.7 29.7)Bacteraemic pneumoniaRR 2.6 (1.5 4.4)MeningitisRR 0.8 (0.2 2.8),血培养: 临床意义,Perez A, Herranz M, Segura M, et al. Epidemiologic impact of blood culture practices and antibiotic consumption on pneumococcal bacteraemia in children. Eur J ClinMicrobiol Infect Dis 2008; 27: 717-724,内容,菌血症的危险因素,年龄 30岁OR 2.0795% CI 1.19 3.60心率 90 bpmOR 1.9095% CI 1.13 3.17体温 37.8COR 2.4295% CI 1.41 4.14白细胞计数 12,000/LOR 2.4095% CI 1.41 4.10应用中心静脉插管OR 1.8995% CI 1.02 3.50LOS 10天OR 2.0295% CI 1.25 3.24Hosmer-Lemeshow拟和优度检验2.99 (P = .981)ROC AUC0.7186,Jaimes F, Arango C, Ruiz G, et al. Predicting bacteremia at the bedside. Clin Infect Dis. 2004 Feb 1;38(3):357-62. Epub 2004 Jan 13.,菌血症的预测指标,Peduzzi P, et al. Predictors of bacteremia and Gram-negative bacteremia in patients with sepsis. Arch Intern Med 1992; 152: 529-535,菌血症的预测指标,Peduzzi P, et al. Predictors of bacteremia and Gram-negative bacteremia in patients with sepsis. Arch Intern Med 1992; 152: 529-535,菌血症: 预测指标,主要标准,次要标准(每项1分),怀疑心内膜炎(3分)体温 39.4C (103.0F) (3分)留置血管内导管(2分),体温38.3 39.3C (101.0 102.9F)年龄 65岁寒战呕吐低血压(收缩压 18,000杆状核 5%血小板 2.0 mg/dL,Shapiro NI, Wolfe RE, Wright SB, et al. Who needs a blood culture? A prospectively derived and validated prediction rule. J Emerg Med 2008; 35(3): 255-264,菌血症: 预测指标,Shapiro NI, Wolfe RE, Wright SB, et al. Who needs a blood culture? A prospectively derived and validated prediction rule. J Emerg Med 2008; 35(3): 255-264,菌血症: 预测指标,Shapiro NI, Wolfe RE, Wright SB, et al. Who needs a blood culture? A prospectively derived and validated prediction rule. J Emerg Med 2008; 35(3): 255-264,鉴别菌血症患者,发热是重要的临床指标BT 38.5C, 低体温, 白细胞增加, 低血压, 意识障碍警惕体温正常的菌血症鉴别引起体温升高的其他疾病内科危重病患者更为复杂,Shafazand S, Weinacker AB. Blood cultures in the critical care unit. Chest 2002; 122: 1727-1736,内容,血培养阳性率的影响因素,血液屏障细菌数量少间断性菌血症血液成分中的杀菌机制(溶酶体, 补体, 中性粒细胞, 抗体)临床和实验室因素采血量抗生素使用血培养数目血培养时机培养时间培养环境培养基,Shafazand S, Weinacker AB. Blood cultures in the critical care unit. Chest 2002; 122: 1727-1736,提高血培养阳性率的措施,Shafazand S, Weinacker AB. Blood cultures in the critical care unit. Chest 2002; 122: 1727-1736,留取血培养前应对皮肤进行充分消毒避免仅留取一套血培养; 24小时内应在不同静脉穿刺部位留取2或3套培养(包括需氧和厌氧瓶)每个培养瓶应至少留取10 mL血标本如从静脉导管留取血标本, 应同时经外周静脉留取, 以帮助鉴别污染菌及真正的致病菌应根据临床情况及微生物实验室的建议使用适当的培养基和收集系统如有可能, 应在应用抗生素前留取血标本. 如果已经使用抗生素, 当抗生素血药浓度达到谷值时留取培养可能提高阳性率,提高血培养阳性率,何时留取血培养皮肤消毒穿刺部位留取血培养次数留取血标本量送检时间是否需要常规留取厌氧培养,采集血培养的时机,菌血症为间断性细菌入血后30 60分钟出现发热寒战NHS应用抗生素之前体温高峰后尽快留取,采集血培养的时机,菌血症发生1 2小时后出现发热寒战1培养的时机体温高峰后尽早留取血培养临床研究结果不支持2,Chandrasekar PH, Brown WJ. Clinical issues of blood cultures. Arch Intern Med 1994; 154: 841-849Li J, Plorde JJ, Carlson LG. Effects of volume and periodicity on blood cultures. J. Clin. Microbiol 1994; 32: 2829-31.,抗生素治疗前后血培养的阳性率,139名患者,抗生素治疗前,抗生素治疗过程中,开始抗生素治疗,83名患者(60%)血培养阴性或分离出污染菌,0/83 (0%)分离到致病菌,56名患者(40%)分离到致病菌,26/56 (45%)分离到致病菌,25名患者(45%)分离到致病的葡萄球菌,19/25 (76%)分离到葡萄球菌,14名患者(25%)分离到致病的链球菌,5/14 (36%)分离到链球菌,17名患者(30%)分离到革兰阴性杆菌,2/17 (12%)分离到革兰阴性杆菌,1/139 (0.72%)分离到新的致病菌,Grace CJ, Lieberman J, Pierce K, et al. Usefulness of Blood Culture for Hospitalized Patients Who Are Receiving Antibiotic Therapy. Clin Infect Dis 2001; 32: 1651-5,临床意义,应用抗生素前进行血培养分离到致病菌的可能性增加2.2倍在开始抗生素治疗最初72小时内, 连续进行血培养的结果, 可以根据应用抗生素前血培养的结果预测极少分离到新的致病菌医生可以等待应用抗生素前的血培养结果回报后, 再进行新的血培养,Grace CJ, Lieberman J, Pierce K, et al. Usefulness of Blood Culture for Hospitalized Patients Who Are Receiving Antibiotic Therapy. Clin Infect Dis 2001; 32: 1651-5,血培养: 留取血标本的时机,对于血流动力学不稳定的患者, 应当在应用抗生素前留取2套血培养,Shafazand S, Weinacker AB. Blood cultures in the critical care unit. Chest 2002; 122: 1727-1736,应用抗生素后的血培养,应当在抗生素达到谷浓度时留取血培养未经过深入研究缺乏临床实用性,Chandrasekar PH, Brown WJ. Clinical issues of blood cultures. Arch Intern Med 1994; 154: 841-849Mylotte JM, Tayara A. Blood cultures: clinical aspects and controversies. Eur J ClinMicrobiol Infect Dis 2000; 19: 157-163,吸附抗生素的血培养瓶,Flayhart D, Borek AP, Wakefield T, et al. Comparison of BACTEC PLUS blood culture media to BacT/Alert FA blood culture media for detection of bacterial pathogens in samples containing therapeutic levels of antibiotics. J ClinMicrobiol 2007; 45(3): 816-821,吸附抗生素的血培养瓶,Flayhart D, Borek AP, Wakefield T, et al. Comparison of BACTEC PLUS blood culture media to BacT/Alert FA blood culture media for detection of bacterial pathogens in samples containing therapeutic levels of antibiotics. J ClinMicrobiol 2007; 45(3): 816-821,血培养: 皮肤消毒减少污染,没有明确证据提示应使用何种消毒剂能够减少假阳性结果使用皮肤消毒包装及含有乙醇的消毒剂可能有帮助,Malani A, Trimble K, Parekh V, et al. Review of clinical trials of skin antiseptic agents used to reduce blood culture contamination. Infect Control Hosp Epidemiol 2007; 28: 892-895,皮肤消毒: 洗必太 vs. 酒精,McLellan E, Townsend R, Parsons HK. Evaluation of ChloraPrep (2% chlorhexidinegluconate in 70% isopropyl alcohol) for skin antisepsis in preparation for blood culture collection. J Infect 2008; 57: 459-463,皮肤消毒: 洗必太 vs. 碘仿,ARR = 3.7%; RRR = 45%; NNT = 28,Suwanpimolkul G, Pongkumpai M, Suankratay C. A randomized trial of 2% chlorhexidine tincture compared with 10% aqueous povidone-iodine for venipuncture site disinfection: effects on blood culture contamination rates. J Infect 2008; 56: 354-359,采集血培养的方法,皮肤消毒后通过静脉穿刺留取动脉血 vs. 静脉血对于多数病原菌没有差异动脉血对播散性真菌感染的检出率稍高,采集血培养的方法: 更换针头,不推荐将血标本注入血培养瓶前更换针头增加针头刺伤的危险轻度降低细菌污染的危险性,Spitalnic SJ, Woolard RH, Mermel LA. The significance of changing needles when inoculating blood cultures: a meta-analysis. Clin Infect Dis 1995;21:1103-6,采集血培养的方法: 血培养次数,第二套或第三套血培养能够增加致病菌的检出率有助于识别污染,血培养次数与阳性率,Lee A, Mirret S, Reller LB, et al. Detection of bloodstream infections in adults: How many blood cultures are needed? J ClinMicrobiol 2007; 45(11): 3546-3548,血培养次数,Shafazand S, Weinacker AB. Blood cultures in the critical care unit. Chest 2002; 122: 1727-1736,血培养次数,Shafazand S, Weinacker AB. Blood cultures in the critical care unit. Chest 2002; 122: 1727-1736,多数情况下, 24小时内无需留取超过2 3套血培养从2 3个不同部位留取血标本应当留取1次以上的血培养有助于鉴别真正菌血症和细菌污染,采集血培养的次数,血培养之间的时间间隔并不明确同时, 间隔2小时, 间隔24小时采血并无差异,Li J, Plorde JJ, Carlson LG. Effects of volume and periodicity on blood cultures. J ClinMicrobiol 1994; 32: 2829-2831,采集血培养的方法: 采血量,成人菌血症时血液中细菌密度 103cfu/mL推荐留取20 30 ml血液血标本每增加1 ml, 培养检出率增加3%,Mermel LA, Maki DG. Detection of bacteremia in adults: consequences of culturing an inadequate volume of blood. Ann Intern Med 1993; 119: 270-272,血培养: 采血量,The higher the volume of blood cultured the higher the yield of blood cultures Washington II JA,Washington JA. Blood cultures: principles and techniques. Mayo Clin Proc 1975; 50: 91-95Washington JA. Evolving concepts on the laboratory diagnosis of septicemia. Infect DisClinPract 1993; 2: 65-69Washington JA II, Ilstrup DM. Blood cultures: issues and controversies. Rev Infect Dis 1986; 8: 792-802,血培养: 采血量,Donnino MW, Goyal N, Terlecki TM, et al. Inadequate blood volume collected for culture: a survey of health care professionals. Mayo Clin Proc 2007; 82(9): 1069-1072,血培养: 采血量,Donnino MW, Goyal N, Terlecki TM, et al. Inadequate blood volume collected for culture: a survey of health care professionals. Mayo Clin Proc 2007; 82(9): 1069-1072,79% 10 mLMean (SD) 6.0 (9.0) mLMedian (IQR) 5 (2, 5) mL,血培养: 采血量,Donnino MW, Goyal N, Terlecki TM, et al. Inadequate blood volume collected for culture: a survey of health care professionals. Mayo Clin Proc 2007; 82(9): 1069-1072,血培养: 采血量,Donnino MW, Goyal N, Terlecki TM, et al. Inadequate blood volume collected for culture: a survey of health care professionals. Mayo Clin Proc 2007; 82(9): 1069-1072,结论大部分医务人员不了解血培养时推荐的最佳采血量,血培养: 采血量与阳性率,Bouza E, Sousa D, Rodriguez-Creixems M, et al. Is the volume of blood cultured still a significant factor in the diagnosis of bloodstream infections? J ClinMicrobiol 2007; 45(9): 2765-2769,OR 0.98795%CI 0.976 0.998P 0.018,OR 1.0495%CI 1.001 1.08P 0.018,血培养: 采血量,Weinstein MP, Mirrett S, Wilson ML, et al. Controlled evaluation of 5 versus 10 milliliters of blood cultured in aerobic BacT/Alert blood culture bottles. J ClinMicrobiol 1994; 32(9): 2103-2106,血培养: 培训的重要性,Connell TG, Rele M, Cowley D, et al. How reliable is a negative blood culture result? Volume of blood submitted for culture in routine practice in a Childrens hospital. Pediatr 2007; 119: 891-896,* 采血量足够指1个月龄以下 0.5 mL, 1 36个月龄者 1.0 mL， 36个月龄者 4.0 mL* 若采血量 1周(19.6 1.6 days)85%接受输血治疗(9.5 0.8 U)静脉采血解释输血量差异的49%,Corwin HL, Parsonnet KC, Gettinger A. RBC transfusion in the ICU. Chest 1995; 108: 767-771,危重病患者的贫血,设计: 前瞻性观察研究背景和患者: 西欧145个ICU的1136名患者结果: 最初24小时内采血次数4.6 (3.2)次45.9%的患者采血 5次采血量10.3 (6.6) ml/次24小时内采血量41.1 (39.7) mLSOFA评分与采血次数(r = 0.34; p 0.001)及采血量(r = 0.28; p 95%)金黄色葡萄球菌大肠杆菌肠杆菌铜绿假单胞菌肺炎链球菌白色念珠菌,常见污染菌( 5%)棒状杆菌属芽孢杆菌属疮疱丙酸杆菌,Towns ML, Quartey SM, Weinstein MP, et al. The clinical significance of positive blood cultures: a prospective, multicenter evaluation, abstr. C-232. In Abstracts of the 93rd General Meeting of the American Society for Microbiology 1993. American Society for Microbiology, Washington, D.C.Weinstein MP, Towns ML, Quartey SM, et al. The clinical significance of positive blood cultures in the 1990s: a prospective comprehensive evaluation of the microbiology, epidemiology, and outcome of bacteremia and fungemia in adults. Clin Infect Dis 1997; 24: 584-602.,血培养: 常见污染菌,Geffers C, Farr BM. Positive predictive value of a percutaneously drawn blood culture growing skin flora varies markedly by organism. Infect Control Hosp Epidemiol 2005; 26(6): 507-509,鉴别困难的分离株,Towns ML, Quartey SM, Weinstein MP, et al. The clinical significance of positive blood cultures: a prospective, multicenter evaluation, abstr. C-232. In Abstracts of the 93rd General Meeting of the American Society for Microbiology 1993. American Society for Microbiology, Washington, D.C.Weinstein MP, Towns ML, Quartey SM, et al. The clinical significance of positive blood cultures in the 1990s: a prospective comprehensive evaluation of the microbiology, epidemiology, and outcome of bacteremia and fungemia in adults. Clin Infect Dis 1997; 24: 584-602.,多种细菌培养阳性,血行性感染通常为单一致病菌血培养分离出多种细菌可能为污染菌6 21%的菌血症为多种细菌引起尤其在高危患者不能仅仅根据血培养分离多种细菌判定为污染菌,血培养阳性次数,Schifman RB, Strand CL, Meier FA, et al. Blood culture contamination: a College of American Pathologists Q-Probes study involving 640 institutions and 497134 specimens from adult patients. Arch Pathol Lab Med 1998; 122: 216-221.Tokars JI. Predictive value of blood cultures positive for coagulase-negative staphylococci: implications for patient care and health care quality assurance. Clin Infect Dis 2004; 39: 333-341,根据阳性培养数鉴别污染菌,Weinstein MP, Reller LB, Murphy JR, et al. The clinical significance of positive blood cultures: a comprehensive analysis of 500 episodes of bacteremia and fungemia in adults. I. Laboratory and epidemiologic observations. Rev Infect Dis 1983; 5: 35-53.,血培养数,血培养阳性比例 (%),心内膜炎,真正的菌血症(非心内膜炎),污染菌,Patterns of positivity in successive blood cultures, showing evidence of the diagnostic importance of separate cultures,血培养次数,333所小型公立医院和私立医院仅仅留取一套血培养的比例12.7% (42.5 3.4%)留取一套血培养比例较低专职的静脉取血人员医院规定至少留取两套血培养医嘱仅留取一套血培养时提醒医生针对留取一套血培养的质控体系,Novis DA, Dale JC, Schifman RB, et al. Solitary blood cultures: a College of American Pathologists Q-Probes study of 132,778 blood culture sets in 333 small hospitals. Arch Pathol Lab Med 2001; 125: 1290-1294.,根据阳性培养数鉴别污染菌,Mirret S, Weinstein MP, Reimer LG, et al. Relevance of the number of positive bottles in determining clinical significance of coagulase-negative Staphylococci in blood cultures. J ClinMicrobiol 2001; 39(9): 3279-81.,根据阳性培养数鉴别污染菌,根据阳性培养数鉴别污染菌,一套血培养通常包括需氧和厌氧培养同一套血培养中阳性培养瓶数不应作为鉴别污染菌和致病菌的依据如果某种细菌更容易在需氧条件下生长,血培养阳性时间,细菌量较大