血培养病原菌分布及污染菌判定的实验室检查

Distribution of pathogens and laboratory examination for identification of contaminants in blood culture

目的通过回顾该院的血培养病原菌检出情况以及污染菌的判定分析,了解该院血流感染的主要病原菌构成比,并证实开展双侧双瓶采血检测等实验室检查方法,能有效提高阳性率和血培养污染菌的判定。方法对该院2010年7～12月的1 121份血培养标本进行回顾性分析,了解其病原菌分布,对部分患者开展双侧双瓶采血检测,以血培养中最常见的污染菌凝固酶阴性葡萄球菌(CNS)为例,评价该方法对血培养污染菌判定的价值。结果血培养阳性检出率为10.0%,主要检出菌种为大肠埃希菌,占25.0%,临床分布和时间分布显示为散发,未见院内感染趋势。其中采用双侧双瓶采血检测的血培养标本98例,阳性检出率达22.5%,高于单侧单瓶采血(9.6%),其中检出CNS的比例为22.7%,双瓶48h内同时检出CNS仅为4.5%,而单瓶检出占18.2%,提示临床CNS可能为污染菌,建议结合患者临床资料、状态综合判断,指导用药。结论血培养检出病原菌种类仍以大肠埃希菌为最高,同往年相似。开展采用双侧双瓶采血方法对判定CNS是否为污染菌有一定作用,可提示临床结合患者具体情况综合判断,减少不合理用药。

Objective To investigate the species and constituent ratio of pathogenic bacteria and confirm the utility of examination method,including two-sides and two-bottles collection to elevate the positive rate and the identification of contaminants in blood culture（BC）,by retrospective analysis of the identification of pathogenic bacteria and contaminants in BC.Methods 1 121 cases of pecimens for BC,collected from July to December in 2010,were retrospectively analyzed to understand the distribution of pathogenic bacteria.Tow-sides and tow-bottles collection of blood specimens were performed in part of patients to evaluate the clinical significance of this method for the identification of contaminants,taking coagulase negative Staphylococcus（CNS） for example.Results The positive rate of BC was 10.0% and 25.0% of clinical isolates were Escherichia coli.The distribution of clinics and time was diverging and there was no tendency of hospital onset of infection.98 cases of patients accepted two-sides and two bottles collection of blood specimens,the positive rate of which was 22.5,higher than single-side and single-bottle collection（9.6%）.The positive rate of CNS in two-set collection group was 22.7%,4.5% were positive with CNS in 48h for tow bottles and 18.2% for one bottle,indicating CNS might be contamination.Conclusion The mainly detected pathogenic bacteria in BC were Escherichia coli.Tow-set collection might be useful for the identification of CNS as contamination,and could supply certain information and reduce unreasonable prescriptions.