Laupland Kevin B, Church Deirdre L, Gregson Daniel B
Department of Medicine, Centre for Anti-microbial Resistance and Infectious Diseases Research Group, University of Calgary, Calgary Health Region, and Calgary Laboratory Services, Calgary, Alberta, Canada.
BMC Infect Dis. 2005 May 17;5:35. doi: 10.1186/1471-2334-5-35.
Blood cultures are a gold standard specific test for diagnosing many infections. However, the low yield may limit their usefulness, particularly in low-risk populations. This study was conducted to assess the utility of blood cultures drawn from ambulatory outpatients.
Blood cultures drawn at community-based collection sites in the Calgary Health Region (population 1 million) in 2001 and 2002 were included in this study. These patients were analyzed by linkages to acute care health care databases for utilization of acute care facilities within 2 weeks of blood culture draw.
3102 sets of cultures were drawn from 1732 ambulatory outpatients (annual rate = 89.4 per 100,000 population). Significant isolates were identified from 73 (2.4%) sets of cultures from 51 patients, including Escherichia coli in 18 (35%) and seven (14%) each of Staphylococcus aureus and Streptococcus pneumoniae. Compared to patients with negative cultures, those with positive cultures were older (mean 49.6 vs. 40.1 years, p < 0.01), and more likely to subsequently receive care at a regional emergency department, outpatient antibiotic clinic, or hospital (35/51 vs. 296/1681, p < 0.0001). Of the 331 (19%) patients who received acute care treatment, those with positive cultures presented sooner after community culture draw (median 2 vs. 3 days, p < 0.01) and had longer median treatment duration (6 vs. 2 days, p < 0.01).
Blood cultures drawn in outpatient settings are uncommonly positive, but may define patients for increased intensity of therapy. Strategies to reduce utilization without excluding patients with positive cultures need to be developed for this patient population.
血培养是诊断多种感染的金标准特异性检测方法。然而，其低阳性率可能会限制其效用，尤其是在低风险人群中。本研究旨在评估从门诊患者采集的血培养的效用。
本研究纳入了2001年和2002年在卡尔加里健康区域（人口100万）基于社区的采集点采集的血培养样本。通过与急性护理医疗数据库进行关联分析这些患者在血培养采集后2周内急性护理设施的使用情况。
从1732名门诊患者中采集了3102套培养样本（年发病率 = 每10万人89.4例）。从51名患者的73套（2.4%）培养样本中鉴定出了重要病原体，其中包括18例（35%）大肠杆菌，金黄色葡萄球菌和肺炎链球菌各7例（14%）。与培养结果为阴性的患者相比，培养结果为阳性的患者年龄更大（平均49.6岁对40.1岁，p < 0.01），并且随后更有可能在区域急诊科、门诊抗生素诊所或医院接受治疗（35/51对296/1681，p < 0.0001）。在接受急性护理治疗的331名（19%）患者中，培养结果为阳性的患者在社区培养采集后就诊时间更早（中位数2天对3天，p < 0.01），且中位治疗持续时间更长（6天对2天，p < 0.01）。
门诊环境下采集的血培养阳性情况不常见，但可能有助于确定需要加强治疗强度的患者。需要针对这一患者群体制定在不排除培养结果为阳性患者的情况下减少医疗资源使用的策略。
