基于原位延时成像算法的快速抗菌药物敏感性测试方法

Rapid antimicrobial susceptibility test based on in-situ time-lapsed imaging of microcolonies

摘要:

【目的】每年有700多万人因抗生素使用不当或不及时而死于细菌感染。抗菌药物敏感性测试(antimicrobial susceptibility test, AST)在临床上被用于指导抗生素治疗，传统的临床检测方法至少需要16−20 h才能获得检测结果，存在局限性。开发基于细菌形态分析的新型快速AST方法，有助于提高诊断效率，为危急重症的细菌感染患者提供及时的治疗。【方法】开发一种原位微菌落延时成像技术，将细菌孵育、抗生素给药、显微成像和图像处理算法相结合。通过成像设备和算法两个维度对齐图像，原位追踪不同浓度抗生素作用下菌落的形态变化，从而判断药敏结果。【结果】经过实验验证，该技术对革兰氏阳性菌和革兰氏阴性菌均有效，可在2 h内测定最低抑菌浓度(minimal inhibitory concentration, MIC)，与临床金标准方法结果一致。【结论】本研究的快速AST方法显著缩短了获得AST报告的时间，并且有望用于更广泛的菌株和抗生素组合。

关键词:霍夫变换;细菌形态;图像识别;快速药敏;原位孵育

Abstract:

[Objective] Over 7 million people die from bacterial infections every year due to the inappropriate or untimely use of antibiotics. Antimicrobial susceptibility test (AST) is a routine method guiding antibiotic therapy in clinical practice, while the existing methods have limitations as they require at least 16–20 h to get the results. We aimed to develop a novel rapid AST method based on bacterial morphology analysis, which can improve the diagnosis efficiency and provide timely treatment for the patients with bacterial infections, especially for urgent cases. [Methods] We developed an in-situ time-lapsed imaging (ISM-TLI) technique for microcolonies by combining bacterial incubation, in vitro antibiotic treatment, microscopic imaging, and image processing algorithm. The combination of the imaging device with the algorithm enabled the tracing of the morphological changes of colonies treated with different concentrations of antibiotics in-situ and the rapid obtainment of AST results. [Results] This technique worked effectively for both Gram-positive and Gram-negative bacteria and could determine the minimum inhibitory concentration (MIC) within 2 h, with the results in agreement with those obtained with the clinical gold standard method. [Conclusion] Our rapid AST technique significantly reduced the turn-around-time for obtaining the AST profile and had great potential for AST of a wide range of other strains.

Key words:Hough transform;bacterial morphology;image recognition;rapid antimicrobial susceptibility test;in-situ incubation