Demidova Natalia, Gunn Jason R, Gitajn Ida Leah, Alex Vitkin Ilya, Elliott Jonathan Thomas, Demidov Valentin V
Dartmouth Health, Department of Orthopaedics, Lebanon, New Hampshire, United States.
University of Toronto, Department of Medical Biophysics, Toronto, Ontario, Canada.
J Biomed Opt. 2025 Apr;30(4):046003. doi: 10.1117/1.JBO.30.4.046003. Epub 2025 Apr 1.
Orthopedic implant-associated infections cause serious complications primarily attributed to bacterial biofilm formation and are often characterized by increased antibiotic resistance and diminished treatment response. Yet, no methods currently exist to identify biofilms intraoperatively-surgeons rely solely on their eyes and hands and cannot detect or differentiate infected tissue to determine the location and extent of contamination.
As the first step in addressing this unmet clinical need, here, we develop an optical coherence tomography (OCT)-based imaging method capable of detection and quantification of one of the most dangerous orthopedic biofilms formed by methicillin-resistant (MRSA).
Growing biofilms on orthopedic hardware, we identify MRSA distinct optical signature through histogram-based multi-parametric texture analysis of OCT images and support the findings with bioluminescence imaging and scanning electron microscopy. Under identical experimental conditions, we identify an optical signature of () biofilms and use it to distinguish and quantify both species within MRSA- biofilms.
The developed OCT-based methodology was successfully tested for (1) MRSA colonies delineation, (2) detection of metal hardware (an important feature for clinical translation where the metal surface of most orthopedic hardware is not flat), (3) automated quantification of biofilm thickness and roughness, and (4) identification of pores and, therefore, ability to evaluate the role of porosity-one of the critical biological metrics in relation to biofilm maturity and response to treatment. For the first time, we demonstrated complex pore structures of thick ( ) MRSA biofilms with an unprecedented level of detail.
The proposed rapid noninvasive detection/quantification of MRSA biofilms on metal surfaces and delineation of their complex network of pores opens new venues for label-free MRSA detection in preclinical models of trauma surgery, expansion to other bacterial strains, and further clinical translation.
骨科植入物相关感染会引发严重并发症，主要归因于细菌生物膜的形成，其特点通常是抗生素耐药性增加且治疗反应减弱。然而，目前尚无术中识别生物膜的方法——外科医生仅依靠肉眼和手感，无法检测或区分感染组织以确定污染的位置和范围。
作为满足这一未被满足的临床需求的第一步，在此我们开发了一种基于光学相干断层扫描（OCT）的成像方法，能够检测和量化耐甲氧西林金黄色葡萄球菌（MRSA）形成的最危险的骨科生物膜之一。
在骨科硬件上培养生物膜，我们通过基于直方图的OCT图像多参数纹理分析确定MRSA独特的光学特征，并通过生物发光成像和扫描电子显微镜支持该发现。在相同实验条件下，我们确定了（）生物膜的光学特征，并用于区分和量化MRSA - 生物膜中的两种菌株。
所开发的基于OCT的方法成功进行了测试，用于（1）MRSA菌落描绘，（2）金属硬件检测（这是临床转化的一个重要特征，因为大多数骨科硬件的金属表面不平整），（3）生物膜厚度和粗糙度的自动量化，以及（4）孔隙识别，因此能够评估孔隙率的作用——这是与生物膜成熟度和治疗反应相关的关键生物学指标之一。我们首次以前所未有的详细程度展示了厚（）MRSA生物膜的复杂孔隙结构。
所提出的对金属表面MRSA生物膜的快速无创检测/量化及其复杂孔隙网络的描绘，为创伤手术临床前模型中无标记MRSA检测、扩展到其他细菌菌株以及进一步的临床转化开辟了新途径。
