血培养阳性菌的分布与报警时间分析

Distribution of positive blood-cultured bacteria and alarming time

目的了解1 056株血培养阳性菌的分布与报警时间的关系,第一时间指导临床医师准确合理选择抗菌药物。方法采用回顾性调查方法,运用χ^2检验和直线相关分析对医院全自动血培养仪检出的1 056株阳性菌的分布及报警时间进行统计分析。结果 1 056株血培养检出的阳性标本中革兰阴性菌427株占40.4%,革兰阳性菌347株占32.8%,真菌78株占7.4%,厌氧菌35株占3.3%,复数菌107株占10.1%,污染菌62株占5.9%;阳性菌主要分布在急诊科、ICU、基本外科、血液肿瘤内科和普通内科;血流感染994株污染62株,报警时间〈12h污染菌占该时间段阳性菌的比率明显低于其他时间段（P〈0.01）;报警时间〈12h、12～24h进行需氧和厌氧培养呈正相关关系（P〈0.01）,其他时间段无法确定是否有直线相关关系。结论血培养阳性菌以葡萄球菌属和埃希菌属为主;血流感染多发生于危急重症患者、外科术后及烧伤病、血液肿瘤病、长期暴露在病原菌周围及免疫力低下等;血培养阳性报警时间结合微生物生长特点可以初步判断是致病菌或污染菌;多数菌在需氧和厌氧培养病原菌报警时间无明显区别,但是同时进行需氧和厌氧培养能提高血培养阳性率。

OBJECTIVE To understand the relationship between the distribution of positive blood-cultured bacteria and the alarming time so as to provide guidance for reasonable clinical use of antibiotics.METHODS By means of the retrospective survey,the chi-square test and linear correlation analysis were employed to performed the statistical analysis of the distribution and alarming time of 1 056 positive strains cultured from the automatic blood culture system.RESULTS Among the 1 056 strains of bacteria cultured from the blood,there were 427（40.4%）strains of gram-negative bacteria,347（32.8%）strains of gram-positive bacteria,and 78（7.4%）strains of fungi;there were 35（3.3%）strains of anaerobic bacteria,107（10.1%）strains of plural bacteria,and 62（5.9%）strains of contaminated bacteria.The positive bacteria mainly distributed in the emergency department,ICU,general surgery department,department of hematology and oncology,and department of internal medicine.Of 994 strains causing the bloodstream infections,62 strains were contaminated,the ratio of the contaminated bacteria to positive bacteria within 12 hours was significantly lower than other time periods（P〈0.01）;the culture of aerobic and anaerobic bacteria with the alarming time within less than 12 hours or 12-24 hours was positively correlated（P〈0.01）;while it was unknown whether there was linear correlation in other time periods.CONCLUSION The Staphylococcus sppand Escherichia sppare the predominant blood-cultured bacteria.The bloodstream infections tend to occur in the critically ill patients,the patients undergoing surgery,the patients with burn wound,the patients with hematological tumors,the patients with long-term exposure to pathogens surrounding,or the patients with low immunity.The alarming time of positive blood culture combined with characteristics of growth of microorganisms can be used for the preliminary identification of the pathogenic bacteria or contaminated bacteria;most of the aerobic and anaerobic pathogens do not vary significantly in the alarming time,however,the culture of the aerobic and anaerobic bacteria at the same time can raise the positive rate of blood culture.