4313份血样细菌培养结果分析
Analysis of 4313 cases of blood culture bacteria

摘要：目的 收集血培养阳性标本的实验室参数和临床参数，结合临床随访和抗感染治疗转归，分析真正致病菌的构成和实验室特征。方法 前瞻性研究2013年3月到2015年3月我院4313份临床送检血培养标本中分离出的483株病原菌，对每份阳性培养结果进行实验室及临床感染参数的收集，并跟踪进行临床随访，了解临床责任医生的经验判断及针对性抗生素治疗的临床转归。综合分析后确定真正的致病菌与污染菌。结果 483株阳性分离菌中，最终判定为致病菌的331株(68.5%)，污染菌97株(20.1%)，不确定致病与否的55株(11.4%)，其中，致病菌中大肠埃希菌所占比例最高，为41.2%，污染菌中凝固酶阴性葡萄球菌比例最高，为75.3%；仅从需氧瓶或厌氧瓶中检出的病原菌为253株(占52.4%)，其中大肠埃希菌在厌氧瓶中检出率(23.9%)高于需氧瓶(13.8%)(P<0.05)；判定为污染的97株阳性分离菌中，仅从1瓶中分离的90株(92.8%)，两瓶以上分离的7株(7.2%)(χ2=142，P<0.05)，24h内报阳的34株(35.1%)，48h内报阳的77株(79.4%)，48h内报阳污染菌的比例高于24h(χ2=38.935，P=0.000)，差异有统计学意义。结论 血培养中污染菌的确立不能简单依靠实验室或临床参数，要同时结合临床医生经验及临床治疗反应综合判断；对于实验室判断污染与否的指标，报阳瓶数和报阳时间依然是2个具有重要价值的因素；重视厌氧瓶的送检更有利于大肠埃希菌的检出。
ABSTRACT: Objective To collect the laboratory parameters and clinical parameters of blood culture positive samples, and analyze the composition and laboratory characteristics of real pathogens by combining with clinical follow-up and anti-infectious treatment outcomes. Methods We conducted a prospective study to isolate the 483 strains of pathogens from 4313 cases of blood samples for clinical examination between March 2013 and March 2015. The results of laboratory and clinical infections were collected for each positive culture and were followed up for clinical follow-up to understand the responsible doctors’ experience-based judgment and targeted clinical treatment of antibiotics. After comprehensive analysis we determined the real pathogens and contaminants. Results Of the 483 positive cultures, 331 were finally determined as pathogenic ones, accounting for 68.5% of the number of positive isolates; 97 were contaminated bacteria (20.1%); and 55 strains with uncertain pathogenic nature (11.4%). Escherichia coli accounted for the highest proportion (41.2%) of pathogenic bacteria. Coagulase-negative staphylococci took up the highest proportion (75.3%) of the contaminated bacteria. As many as 253 strains (52.4%) were detected from the aerobic or anaerobic bottles. The detection rate of Escherichia coli in anaerobic bottles (23.9%) was higher than that in aerobic bottles (13.8%) (P<0.05). Of 97 strains of positive isolates, only one bottle was reported positive for 90 strains, accounting for (92.8%), and more than two bottles of 7 positive strains, accounting for (7.2%) (P<0.05). 34 positive in 24h (35.1%), 77 positive in 48h (79.4%), the positive bacteria ratio within 48h (79.4%) was higher than that of bacteria contamination ratio within 24h (χ2=38.935, P=0.000), with a significant difference. Conclusion Establishment of contaminated bacteria in blood culture cannot rely solely on laboratory or