Allen Elizabeth R, van Diemen Pauline, Yamaguchi Yuko, Lindemann Claudia, Soilleux Elizabeth, Rollier Christine, Hill Fergal, Schneider Jurgen, Wyllie David H
Jenner Institute, Centre for Cellular and Molecular Physiology, University of Oxford, Oxford, United Kingdom.
Nuffield Department of Clinical Laboratory Sciences, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.
PLoS One. 2016 May 26;11(5):e0154705. doi: 10.1371/journal.pone.0154705. eCollection 2016.
To develop and validate a sensitive and specific method of abscess enumeration and quantification in a preclinical model of Staphylococcus aureus infection.
S. aureus infected murine kidneys were fixed in paraformaldehyde, impregnated with gadolinium, and embedded in agar blocks, which were subjected to 3D magnetic resonance microscopy on a 9.4T MRI scanner. Image analysis techniques were developed, which could identify and quantify abscesses. The result of this imaging was compared with histological examination. The impact of a S. aureus Sortase A vaccination regime was assessed using the technique.
Up to 32 murine kidneys could be imaged in a single MRI run, yielding images with voxels of about 25 μm3. S. aureus abscesses could be readily identified in blinded analyses of the kidneys after 3 days of infection, with low inter-observer variability. Comparison with histological sections shows a striking correlation between the two techniques: all presumptive abscesses identified by MRI were confirmed histologically, and histology identified no abscesses not evident on MRI. In view of this, simulations were performed assuming that both MRI reconstruction, and histology examining all sections of the tissue, were fully sensitive and specific at abscess detection. This simulation showed that MRI provided more sensitive and precise estimates of abscess numbers and volume than histology, unless at least 5 histological sections are taken through the long axis of the kidney. We used the MRI technique described to investigate the impact of a S. aureus Sortase A vaccine.
Post mortem MRI scanning of large batches of fixed organs has application in the preclinical assessment of S. aureus vaccines.
在金黄色葡萄球菌感染的临床前模型中开发并验证一种灵敏且特异的脓肿计数和定量方法。
将感染金黄色葡萄球菌的小鼠肾脏用多聚甲醛固定，用钆浸渍，然后包埋在琼脂块中，在9.4T磁共振成像扫描仪上进行三维磁共振显微镜检查。开发了图像分析技术，可识别和定量脓肿。将该成像结果与组织学检查结果进行比较。使用该技术评估金黄色葡萄球菌分选酶A疫苗接种方案的影响。
单次磁共振成像扫描可对多达32个小鼠肾脏进行成像，生成体素约为25μm³的图像。在感染3天后对肾脏进行盲法分析时，可轻松识别出金黄色葡萄球菌脓肿，观察者间变异性较低。与组织学切片的比较显示两种技术之间存在显著相关性：磁共振成像识别出的所有疑似脓肿经组织学证实，组织学未发现磁共振成像上不明显的脓肿。鉴于此，进行了模拟，假设磁共振成像重建和组织学检查组织的所有切片在脓肿检测方面均具有完全的敏感性和特异性。该模拟表明，除非沿肾脏长轴至少取5个组织学切片，否则磁共振成像在脓肿数量和体积的估计方面比组织学更灵敏、更精确。我们使用所描述的磁共振成像技术研究了金黄色葡萄球菌分选酶A疫苗的影响。
对大量固定器官进行死后磁共振成像扫描可应用于金黄色葡萄球菌疫苗的临床前评估。
