Background: 

Despite its well-established limitations, culture remains the gold standard for microbial identification in periprosthetic joint infection (PJI). However, there are no benchmarks for the time to positivity (TTP) on culture for specific microorganisms. This study aimed to determine the TTP for pathogens commonly encountered in PJI.

Methods: 

This retrospective, multicenter study reviewed prospectively maintained institutional PJI databases to identify patients who underwent hip or knee revision arthroplasty from 2017 to 2021 at 2 tertiary centers in the United States and Germany. Only patients who met the 2018 International Consensus Meeting (ICM) criteria for PJI and had a positive intraoperative culture were included. TTP on culture media was recorded for each sample taken intraoperatively. The median TTP was compared among different microbial species and different specimen types. Data are presented either as the mean and the standard deviation or as the median and the interquartile range (IQR).

Results: 

A total of 536 ICM-positive patients with positive cultures were included. The mean number of positive cultures per patient was 3.9 ± 2.6. The median TTP, in days, for all positive cultures was 3.3 (IQR, 1.9 to 5.4). Overall, gram-negative organisms (TTP, 1.99 [1.1 to 4.1]; n = 225) grew significantly faster on culture compared with gram-positive organisms (TTP, 3.33 [1.9 to 5.8]; n = 1,774). Methicillin-resistant Staphylococcus aureus (TTP, 1.42 [1.0 to 2.8]; n = 85) had the fastest TTP, followed by gram-negative rods (TTP, 1.92 [1.0 to 3.9]; n = 163), methicillin-sensitive Staphylococcus aureus (TTP, 1.95 [1.1 to 3.3] n = 393), Streptococcus species (TTP, 2.92 [1.2 to 4.3]; n = 230), Staphylococcus epidermidis (TTP, 4.20 [2.4 to 5.5]; n = 555), Candida species (TTP, 5.30 [3.1 to 10]; n = 63), and Cutibacterium acnes (TTP, 6.97 [5.9 to 8.2]; n = 197). When evaluating the median TTP according to specimen type, synovial fluid (TTP, 1.97 [1.1 to 3.1]; n = 112) exhibited the shortest TTP, followed by soft tissue (TTP, 3.17 [1.4 to 5.3]; n = 1,199) and bone (TTP, 4.16 [2.3 to 5.9]; n = 782).

Conclusions: 

To our knowledge, this is the first study to examine the TTP of common microorganisms that are known to cause PJI. Increased awareness of these data may help to guide the selection of appropriate antimicrobial therapy and to predict treatment outcomes in the future. Nonetheless, additional studies with larger cohorts are needed to validate these benchmarks.

Level of Evidence: 

Diagnostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

中文翻译：

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假体周围关节感染培养阳性的时间

背景： 

尽管存在公认的局限性，但培养仍然是假体周围关节感染 (PJI) 中微生物鉴定的金标准。但是，对于特定微生物培养的阳性时间 (TTP) 没有基准。本研究旨在确定 PJI 中常见病原体的 TTP。

方法： 

这项回顾性多中心研究回顾了前瞻性维护的机构 PJI 数据库，以确定 2017 年至 2021 年在美国和德国的 2 个三级中心接受髋关节或膝关节翻修术的患者。仅纳入符合 2018 年国际共识会议 (ICM) PJI 标准且术中培养呈阳性的患者。为术中采集的每个样本记录培养基上的 TTP。比较了不同微生物种类和不同标本类型的中位 TTP。数据以均值和标准差或中位数和四分位距 (IQR) 的形式呈现。

结果： 

总共包括 536 名培养阳性的 ICM 阳性患者。每名患者的平均阳性培养数为 3.9 ± 2.6。所有阳性培养物的中位 TTP（以天为单位）为 3.3（IQR，1.9 至 5.4）。总体而言，与革兰氏阳性生物体（TTP，3.33 [1.9 至 5.8]；n = 1,774）相比，革兰氏阴性生物体（TTP，1.99 [1.1 至 4.1]；n = 225）在培养中生长明显更快。耐甲氧西林金黄色葡萄球菌（TTP，1.42 [1.0 至 2.8]；n = 85）的 TTP 最快，其次是革兰氏阴性杆菌（TTP，1.92 [1.0 至 3.9]；n = 163），甲氧西林敏感金黄色葡萄球菌（TTP，1.95 [1.1 至 3.3] n = 393），链球菌属（TTP，2.92 [1.2 至 4.3]；n = 230），表皮葡萄球菌（TTP，4.20 [2.4 至 5.5]；n = 555）、念珠菌属（TTP，5.30 [3.1 至 10]；n = 63）和痤疮杆菌（TTP，6.97 [5.9 至 8.2]；n = 197 ）。根据标本类型评估中位 TTP 时，滑液（TTP，1.97 [1.1 至 3.1]；n = 112）表现出最短的 TTP，其次是软组织（TTP，3.17 [1.4 至 5.3]；n = 1,199）和骨（TTP，4.16 [2.3 至 5.9]；n = 782）。

结论： 

据我们所知，这是第一项检查已知会导致 PJI 的常见微生物的 TTP 的研究。提高对这些数据的认识可能有助于指导选择适当的抗菌疗法并预测未来的治疗结果。尽管如此，还需要更多的队列研究来验证这些基准。

证据等级： 

诊断四级。有关证据等级的完整描述，请参阅作者须知。