Renz Nora, Cabric Sabrina, Morgenstern Christian, Schuetz Michael A, Trampuz Andrej
Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Center for Musculoskeletal Surgery (CMSC), Berlin, Germany.
Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Center for Musculoskeletal Surgery (CMSC), Berlin, Germany; Berlin-Brandenburg Center for Regenerative Therapies, Berlin, Germany.
Injury. 2018 Apr;49(4):806-811. doi: 10.1016/j.injury.2018.02.018. Epub 2018 Feb 21.
Bone healing disturbance following fracture fixation represents a continuing challenge. We evaluated a novel fully automated polymerase chain reaction (PCR) assay using sonication fluid from retrieved orthopedic hardware to diagnose infection.
In this prospective diagnostic cohort study, explanted orthopedic hardware materials from consecutive patients were investigated by sonication and the resulting sonication fluid was analyzed by culture (standard procedure) and multiplex PCR (investigational procedure). Hardware-associated infection was defined as visible purulence, presence of a sinus tract, implant on view, inflammation in peri-implant tissue or positive culture. McNemar's chi-squared test was used to compare the performance of diagnostic tests. For the clinical performance all pathogens were considered, whereas for analytical performance only microorganisms were considered for which primers are included in the PCR assay.
Among 51 patients, hardware-associated infection was diagnosed in 38 cases (75%) and non-infectious causes in 13 patients (25%). The sensitivity for diagnosing infection was 66% for peri-implant tissue culture, 84% for sonication fluid culture, 71% (clinical performance) and 77% (analytical performance) for sonication fluid PCR, the specificity of all tests was >90%. The analytical sensitivity of PCR was higher for gram-negative bacilli (100%), coagulase-negative staphylococci (89%) and Staphylococcus aureus (75%) than for Cutibacterium (formerly Propionibacterium) acnes (57%), enterococci (50%) and Candida spp. (25%).
The performance of sonication fluid PCR for diagnosis of orthopedic hardware-associated infection was comparable to culture tests. The additional advantage of PCR was short processing time (<5 h) and fully automated procedure. With further improvement of the performance, PCR has the potential to complement conventional cultures.
骨折固定后骨愈合障碍仍是一个持续存在的挑战。我们评估了一种新型全自动聚合酶链反应（PCR）检测方法，该方法使用取自取出的骨科植入物的超声处理液来诊断感染。
在这项前瞻性诊断队列研究中，对连续患者取出的骨科植入物材料进行超声处理，并对所得超声处理液进行培养（标准程序）和多重PCR分析（研究程序）。与植入物相关的感染定义为可见脓性分泌物、存在窦道、植入物外露、植入物周围组织炎症或培养阳性。采用McNemar卡方检验比较诊断试验的性能。对于临床性能，考虑所有病原体，而对于分析性能，仅考虑PCR检测中包含引物的微生物。
51例患者中，38例（75%）诊断为与植入物相关的感染，13例（25%）为非感染性原因。植入物周围组织培养诊断感染的敏感性为66%，超声处理液培养为84%，超声处理液PCR的临床性能为71%，分析性能为77%，所有检测的特异性均>90%。PCR对革兰氏阴性杆菌（100%）、凝固酶阴性葡萄球菌（89%）和金黄色葡萄球菌（75%）的分析敏感性高于痤疮丙酸杆菌（原丙酸杆菌，57%）、肠球菌（50%）和念珠菌属（25%）。
超声处理液PCR诊断骨科植入物相关感染的性能与培养试验相当。PCR的额外优势是处理时间短（<5小时）且为全自动程序。随着性能的进一步提高，PCR有可能补充传统培养方法。
