McCann Chase D, Moore Miranda S, May Larissa S, McCarroll Matthew G, Jordan Jeanne A
Department of Epidemiology and Biostatistics, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA.
Department of Emergency Medicine, The George Washington University Medical Faculty Associates, Washington, DC, USA.
Diagn Microbiol Infect Dis. 2015 Mar;81(3):158-62. doi: 10.1016/j.diagmicrobio.2014.11.014. Epub 2014 Dec 3.
Several molecular platforms can identify bacteria associated with bloodstream infections but require positive culture bottles as starting material. Here, we describe results of screening 1140 blood cultures at 8h postinoculation, from 918 eligible adults being evaluated for bloodstream infection. DNA was extracted and analyzed by 16S and/or 23S rRNA real-time PCR/pyrosequencing. Compared to culture, PCR/pyrosequencing displayed 90.9% sensitivity, 99.6% specificity, 95.7% positive predictive value, and 99.1% negative predictive value. Overall concordance rate was 98.9% (1127/1140). In 4 cases with molecular-positive/culture-negative results, medical chart reviews provided evidence of identical bacteria from subsequent blood or concomitant urine/sputum cultures. Nine culture-positive/molecular-negative cases were associated with either polymicrobial growth, grew only in the anaerobic bottle of the clinical pair, and/or were detected by PCR/pyrosequencing after 8h. In summary, this approach accurately detected and identified bacteria in ~91% of culture-confirmed cases significantly sooner than the phenotypic identification was available, having the potential to improve antibiotic stewardship.
几种分子平台能够识别与血流感染相关的细菌，但需要以阳性培养瓶作为起始材料。在此，我们描述了对918名因血流感染接受评估的合格成年人接种8小时后的1140份血培养物进行筛查的结果。提取DNA并通过16S和/或23S rRNA实时PCR/焦磷酸测序进行分析。与培养法相比，PCR/焦磷酸测序显示出90.9%的灵敏度、99.6%的特异性、95.7%的阳性预测值和99.1%的阴性预测值。总体符合率为98.9%（1127/1140）。在4例分子检测阳性/培养阴性的病例中，病历审查提供了后续血培养或同时进行的尿/痰培养中相同细菌的证据。9例培养阳性/分子检测阴性的病例与以下情况相关：混合菌生长、仅在临床配对的厌氧瓶中生长，和/或在8小时后通过PCR/焦磷酸测序检测到。总之，这种方法在约91%经培养确认的病例中能够比表型鉴定更快地准确检测和识别细菌，具有改善抗生素管理的潜力。
