DeBurger Barbara, Hanna Sarah, Powell Eleanor A, Ventrola Cindi, Mortensen Joel E
Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229 USA.
BMC Clin Pathol. 2017 Apr 8;17:7. doi: 10.1186/s12907-017-0043-2. eCollection 2017.
The BD MAX™ Enteric Bacterial Panel (BDM-EBP) is designed and FDA-cleared to detect and Shiga toxin genes from stool samples. However, rectal swabs, which are not FDA-cleared for clinical testing with the BDM-EBP, are common specimens received from pediatric patients for enteric pathogen testing. The purpose of this study was to evaluate the ability of the BDM-EBP to detect stool pathogens from rectal swabs.
Routine cultures, Shiga toxin testing, and molecular testing with BDM-EBP were performed on 272 sequential rectal swabs collected from August 2015 to December 2015. Discrepant test results were resolved using Verigene® Enteric Pathogens Nucleic Acid Test (EP). 36 challenge samples (13 spp., 3 spp., 10 spp., and 10 Shiga toxin positive ) were tested using reference strains (American Type Culture Collection) and previous patient isolates diluted to10-10 cfu/ml in saline then added to Sample Buffer Tube (SBT) with negative stool matrix delivered via a swab. Limit of detection testing was performed by serial 10 fold dilutions in saline then added to SBT with negative stool matrix provided via a swab.
A total of 272 rectal swab specimens were evaluated and 89 were positive by culture and/or MAX EBP. All discrepant results were BDM-EBP positive and culture negative. 21 of 31 (68%) of the apparent false positive BDM-EBP discrepant results resolved as positive with Nanosphere's Verigene® EP. After resolution of the discordant results, the Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) are as follows for each target: ( = 4) 100%, PPA and 100%, NPA; ( = 79) 100%, PPA and 95.3%, NPA; ( = 4) 100%, PPA and 99.6%, NPA; and Shiga toxin producing organisms ( = 2) 100%, PPA and 100%, NPA. 8.8% of the patient samples did not initially yield a result on the BDM-System. Upon repeat, half of the problematic samples resolved, and 4.4% of the total specimen tested did not yield a result. All organisms in the challenge samples were detected. Limits of detection for BDM-EBP testing of rectal swabs were as follows (in cfu/ml in SBT): -1.44 × 10; -5.10 × 10; -1.51 × 10; and Shiga Toxin-1.13 ×10.
Rectal swabs are acceptable samples for detecting , , , and Shiga toxin using BDM-EBP.
BD MAX™肠道细菌检测板（BDM-EBP）经设计并获美国食品药品监督管理局（FDA）批准，可从粪便样本中检测[具体细菌名称1]、[具体细菌名称2]和志贺毒素基因。然而，直肠拭子并非经FDA批准可用于BDM-EBP临床检测的样本，却是儿科患者肠道病原体检测中常见的送检样本。本研究旨在评估BDM-EBP从直肠拭子中检测粪便病原体的能力。
对2015年8月至2015年12月收集的272份连续直肠拭子进行常规培养、志贺毒素检测以及BDM-EBP分子检测。使用Verigene®肠道病原体核酸检测（EP）解决不一致的检测结果。使用参考菌株（美国典型培养物保藏中心）和先前患者分离株在盐水中稀释至10⁻¹⁰cfu/ml，然后添加到带有通过拭子提供的阴性粪便基质的样本缓冲管（SBT）中，对36个挑战样本（13种[具体细菌名称1]、3种[具体细菌名称2]、10种[具体细菌名称3]和10种志贺毒素阳性样本）进行检测。通过在盐水中连续10倍稀释然后添加到通过拭子提供的带有阴性粪便基质的SBT中进行检测限测试。
共评估了272份直肠拭子标本，其中89份通过培养和/或MAX EBP检测为阳性。所有不一致的结果均为BDM-EBP阳性而培养阴性。31份明显的BDM-EBP假阳性不一致结果中有21份（68%）经Nanosphere公司的Verigene® EP检测确认为阳性。解决不一致结果后，每个检测目标的阳性百分比一致性（PPA）和阴性百分比一致性（NPA）如下：[具体细菌名称1]（n = 4）PPA为100%，NPA为100%；[具体细菌名称2]（n = 79）PPA为100%，NPA为95.3%；[具体细菌名称3]（n = 4）PPA为100%，NPA为99.6%；产志贺毒素生物体（n = 2）PPA为100%，NPA为100%。8.8%的患者样本最初在BDM系统上未得出结果。重复检测后，一半有问题的样本得到解决，且总检测样本中有4.4%未得出结果。挑战样本中的所有生物体均被检测到。直肠拭子BDM-EBP检测的检测限如下（SBT中的cfu/ml）：[具体细菌名称1] -1.44×10；[具体细菌名称2] -5.10×10；[具体细菌名称3] -1.51×10；志贺毒素 -1.13×10。
直肠拭子是使用BDM-EBP检测[具体细菌名称1]、[具体细菌名称2]、[具体细菌名称3]和志贺毒素的可接受样本。
