Bacterial DNA enrichment for low-inoculum fracture-related infection diagnostic using high-throughput sequencing.

One of the main barriers for the implementation of metagenomic sequencing in routine diagnosis of infectious diseases is the presence of host DNA. While several enrichment methods are likely to overcome this issue, their effectiveness for specimens such as bone in the case of chronic infections remains to be determined. We compared the relevance of two methods for bacterial DNA enrichment when compared to a reference protocol during pretreatment of bone samples from fracture-related infections before HTS by both Illumina Miseq and Oxford Nanopore Technology (ONT). The bacterial/human DNA ratio was higher for either protocols than the reference technique (p = 0.00012), without any significant difference between them. HTS sensitivity over culture ranged from 21.7 % to 85 %. The ability of the studied protocols to improve the bacterial/human DNA ratio depends on the sequencing technique employed. In this context, there is room for improvement in enhancing the sensitivity of HTS for diagnostic purpose.