Peng Jiayi, Bai Huili, Li Ying, Luo Huating, Li Jiajun, Dai Haifeng, Wang Hongmei, Meng Tao, Zhang Jia, Wang Zhijian, Chen Xuanxin, Cheng Wei, Peng Yan, Huang Wenxiang
Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
The Center for Clinical Molecular Detection, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
Front Cell Infect Microbiol. 2025 Jul 10;15:1605795. doi: 10.3389/fcimb.2025.1605795. eCollection 2025.
Bloodstream infection (BSI) exhibits elevated mortality, particularly among elderly patients manifesting atypical symptoms. Although blood culture (BC) remains the diagnostic gold standard, its limited sensitivity and prolonged turnaround time impede early detection. Droplet digital polymerase chain reaction (ddPCR), a novel pathogen detection method with superior sensitivity and rapid results, demonstrates significant diagnostic and prognostic for BSI. However, heightened sensitivity may increase false positive rates, with elderly patients particularly susceptible to specimen contamination and transient bacteremia.
This retrospective study employed clinical judgment as the diagnostic reference. Patients were stratified into BSI and non-BSI groups, with data collected on ddPCR and BC results, imaging and laboratory findings, medication response, and discharge outcomes. The diagnostic accuracy and antibiotic guidance efficacy of ddPCR and BC were compared, and the clinical utility of ddPCR was evaluated for prognostic assessment and false positive identification.
The analysis encompassed 355 episodes from 280 elderly patients with suspected BSI. ddPCR demonstrated significantly higher detection rates compared to BC in BSI group (59.33% versus 20.57%). Combined implementation increased detection to 65.07%. Regardless of clinical judgment (59.61% versus 20.57%) or alternative microbiological tests (90.63% versus 7.14%) served as the reference standards, ddPCR exhibited superior sensitivity to BC. No significant differences emerged in antibiotic adjustment rates or therapeutic efficacy between ddPCR and BC. Elevated microbial species diversity correlated with unfavorable discharge outcomes (P<0.001, OR=2.122). Multiple follow-up ddPCR monitoring revealed progressive increases in the number of species and the copies of some (or all) species among patients with poor outcomes, contrasting with decreasing trends in those with favorable outcomes. When detecting , coagulase-negative (CoNS), complex, and , diagnostic thresholds of 132.55, 182.70/262.24, and 174.78 copies/mL, respectively, were established to help differentiate false-positive results.
The combination of ddPCR with BC improves BSI diagnosis in elderly patients and facilitates antibiotic treatment optimization. Moreover, ddPCR demonstrates potential for prognostic evaluation and false-positive discrimination. Nevertheless, these findings require further validation through large-scale prospective studies employing predefined clinical criteria.
血流感染（BSI）的死亡率较高，尤其是在表现出非典型症状的老年患者中。尽管血培养（BC）仍然是诊断的金标准，但其有限的敏感性和较长的周转时间阻碍了早期检测。滴液数字聚合酶链反应（ddPCR）是一种新型病原体检测方法，具有更高的敏感性和快速的结果，对BSI具有显著的诊断和预后价值。然而，更高的敏感性可能会增加假阳性率，老年患者尤其容易受到标本污染和短暂菌血症的影响。
本回顾性研究采用临床判断作为诊断参考。将患者分为BSI组和非BSI组，收集ddPCR和BC结果、影像学和实验室检查结果、药物反应及出院结局等数据。比较ddPCR和BC的诊断准确性及抗生素指导疗效，并评估ddPCR在预后评估和假阳性识别方面的临床应用价值。
分析纳入了280例疑似BSI的老年患者的355次发作。在BSI组中，ddPCR的检测率显著高于BC（59.33%对20.57%）。联合应用可将检测率提高到65.07%。无论以临床判断（59.61%对20.57%）还是其他微生物检测（90.63%对7.14%）作为参考标准，ddPCR对BC均表现出更高的敏感性。ddPCR和BC在抗生素调整率或治疗效果方面无显著差异。微生物种类多样性增加与不良出院结局相关（P<0.001，OR=2.122）。多次随访ddPCR监测显示，预后不良患者的菌种数量及部分（或全部）菌种的拷贝数呈逐渐增加趋势，而预后良好患者则呈下降趋势。在检测凝固酶阴性葡萄球菌（CoNS）、真菌复合体和肠球菌时，分别设定诊断阈值为132.55、182.70/262.24和174.78拷贝/mL，以帮助区分假阳性结果。
ddPCR与BC联合应用可提高老年患者BSI的诊断率，并有助于优化抗生素治疗。此外，ddPCR在预后评估和假阳性鉴别方面具有潜力。然而，这些发现需要通过采用预定义临床标准的大规模前瞻性研究进一步验证。
