Beyond the colony-forming-unit: Rapid bacterial evaluation in Osteomyelitis

Examination of bacteria/host cell interactions is important for understanding the aetiology of many infectious diseases. The colony-forming-unit (CFU) has been the standard for quantifying bacterial burden for the past century, however, this suffers from low sensitivity and is dependent on bacterial culturability in vitro. Our data demonstrate the discrepancy between the CFU and bacterial genome copy number in an osteomyelitis-relevant co-culture system and we confirm diagnosis and quantify bacterial load in clinical bone specimens. This study provides insight into improving the quantification of bacterial burden in such cases.

Methods
The DNA sequences were generated by Oxford Nanopore sequencing platform, using the PCR amplicons following the enrichment of bacterial signal from total DNA isolated from clinical bone specimens.

细菌与宿主细胞相互作用的研究，对于阐明多种传染病的病因学至关重要。菌落形成单位（colony-forming-unit, CFU）在过去一个世纪中一直是量化细菌负荷的标准方法，但其存在灵敏度较低的缺陷，且依赖于细菌的体外可培养特性。本研究数据显示，在与骨髓炎相关的共培养体系中，CFU与细菌基因组拷贝数之间存在显著差异；同时我们证实了临床骨标本的细菌诊断结果，并完成了细菌载量的定量分析。本研究为优化此类场景下的细菌负荷量化手段提供了新的见解。

方法
本研究的DNA序列通过牛津纳米孔（Oxford Nanopore）测序平台生成，具体流程为：从临床骨标本中提取总DNA，富集细菌信号后，通过PCR扩增得到扩增子，以此进行测序。