Namdari Surena, Nicholson Thema, Parvizi Javad
Rothman Institute, Thomas Jefferson University, Department of Orthopaedic Surgery, Philadelphia, PA, USA.
Arch Bone Jt Surg. 2020 Jul;8(4):506-510. doi: 10.22038/abjs.2020.40642.2095.
Given high rates of positive () cultures in cases of both primary and revision shoulder surgery, the ramifications of positive cultures remain uncertain. Next generation sequencing (NGS) is a molecular tool that sequences the whole bacterial genome and is capable of identifying pathogens and the relative percent abundance in which they appear within a sample. The purpose of this study was to report the false positive culture rate in negative control specimens and to determine whether NGS has potential value in reducing the rate of false positive results.
Between April 2017 and May 2017 swabs were taken during primary shoulder arthroplasty. After surgical time out, using sterile gloves, a sterile swab was opened and exposed to the air for 5 seconds, returned to its contained, and sealed. One swab was sent to our institution's microbiology laboratory for aerobic and anaerobic culture and held for 13 days. The other sample was sent for NGS (MicroGen Dx, Lubbock, TX), where samples were amplified for pyrosequencing using a forward and reverse fusion primer and matched against a DNA library for species identification.
For 40 consecutive cases, swabs were sent for culture and NGS. was identified by culture in 6/40 (15%) swabs and coagulase negative staphylococcus (CNS) was identified in 3/40 (7.5%). Both cases with positive NGS sequencing reported polymicrobial results with one sample (2.5%), including a relative abundance of 3% . At 90 days after surgery, there were no cases of clinical infection in any of the 40 cases.
We demonstrate that the two most commonly cultured organisms ( and CNS) during revision shoulder arthroplasty are also the two most commonly cultured organisms from negative control specimens. Contamination can come from air in the operating room or laboratory contamination.
鉴于初次和翻修肩关节手术病例中（）培养阳性率较高，培养阳性的后果仍不明确。下一代测序（NGS）是一种对整个细菌基因组进行测序的分子工具，能够识别病原体及其在样本中出现的相对丰度百分比。本研究的目的是报告阴性对照标本中的假阳性培养率，并确定NGS在降低假阳性结果率方面是否具有潜在价值。
2017年4月至2017年5月期间，在初次肩关节置换术中采集拭子。手术暂停后，使用无菌手套打开无菌拭子，暴露于空气中5秒，放回容器并密封。一支拭子送至本机构微生物实验室进行需氧和厌氧培养，并保存13天。另一个样本送去进行NGS检测（MicroGen Dx，得克萨斯州拉伯克），在那里使用正向和反向融合引物对样本进行焦磷酸测序扩增，并与DNA文库进行比对以进行物种鉴定。
连续40例病例的拭子送去进行培养和NGS检测。6/40（15%）的拭子培养鉴定出（），3/40（7.5%）的拭子培养鉴定出凝固酶阴性葡萄球菌（CNS）。NGS测序阳性的两例病例均报告一个样本为多微生物结果（2.5%），包括相对丰度为3%的（）。术后90天，40例病例中均无临床感染病例。
我们证明，翻修肩关节置换术中最常培养的两种微生物（和CNS）也是阴性对照标本中最常培养的两种微生物。污染可能来自手术室空气或实验室污染。
