Department of Respiratory Medicine, Hannover Medical School, Hannover, Germany.
Intensive Care Med. 2011 Jul;37(7):1069-76. doi: 10.1007/s00134-011-2245-x. Epub 2011 May 15.
Polymerase chain reaction (PCR)-based techniques allow more rapid and sensitive detection of pathogens compared with conventional blood culture. Nevertheless, the climate of opinion of relevant studies is that currently PCR can supplement but not replace blood culture. In numerous studies, combined detection rate of both methods was significantly higher compared with PCR or blood culture alone. Also, complete determination of antibiotic resistance can currently be performed only by blood culture. Further increase of the panel of multiplex PCR is complicated, because the vast majority of sepsis pathogens are already included, primer interactions leading to primer heteromers limit the amount of targets detectable within one PCR tube, and an array of too many individual PCR reactions for investigation of a single specimen leads to high cost and workload. Except for diagnostics of patients in whom unusual, not culturable, or fastidious pathogens are detected more often, such as immunosuppressed patients with suspected parasitic infection, etc., it might even not be necessary to further increase the spectrum of detectable species. If the primary aim of PCR diagnostics is to decrease inappropriate empirical treatment and improve patient outcome, detection should focus on those pathogens or resistance determinants that are not covered by guideline-recommended treatment regimens and that have been identified as the major cause of inappropriate treatment according to current studies. In our opinion, such a narrower assay is more cost effective, may achieve higher accuracy due to reduced intratest interference, and would better address current and emerging clinical needs.
聚合酶链反应（PCR）技术与传统的血液培养相比，能够更快速、更灵敏地检测病原体。然而，相关研究的主流观点认为，目前 PCR 可以作为血液培养的补充，而不能替代后者。在许多研究中，两种方法联合检测的阳性率明显高于单独使用 PCR 或血液培养。此外，目前只能通过血液培养来确定抗生素的耐药性。进一步增加多重 PCR 的检测项目是复杂的，因为绝大多数脓毒症病原体已经包含在内，引物相互作用导致引物异源二聚体限制了一个 PCR 管内可检测的靶标数量，而且过多的单个 PCR 反应用于单个标本的检测会导致成本和工作量增加。除了对疑似寄生虫感染等免疫抑制患者等经常检测到不常见、不可培养或难培养的病原体的患者进行诊断外，可能甚至没有必要进一步增加可检测物种的范围。如果 PCR 诊断的主要目的是减少不适当的经验性治疗并改善患者的预后，那么检测应集中于那些未被指南推荐的治疗方案涵盖的病原体或耐药决定因素，并且根据当前的研究确定为不适当治疗的主要原因。在我们看来，这种更窄的检测方法更具成本效益，由于减少了检测内干扰，可能会获得更高的准确性，并能更好地满足当前和新出现的临床需求。
