TABLE 2.

The methods for metagenomic sequencing and analysis of discs of this study were compared to two prior disc metagenomic studies of Rajasekaran et al. ⁹ and Astur et al. ⁶ study.

	Our study	Rajasekaran et al. 9	Astur et al. 6
Patients	70 (24 nonMC, 25 MC1, 21 MC2)	40 (20 non‐Modic, 20 Modic, 20 Control)	17 (herniated discs)
Patient average age	63 (From 13 to 89 years)	47 (From 19 to 70 years)	42.8 years (From 31 to 59 years)
Variable region used	V3‐V4 (341F and 806R)	V3‐V4 (341F and 806R)	V3‐V4
Filtered for human genome content	Yes, with Bowtie2 (reference genome GRCh38p13)	No	No
DNA extraction	QIAmp UCP Pathogen Mini Kit	QIAmp DNA Microbiome Kit	QIAmp DNA Microbiome Kit
Contamination controls	10 tubes included	N/A	N/A
Sequencing platform	Illumina	Illumia NovoSeq 6000	Illumina
Decontamination strategy	Decontam R package	N/A	N/A
Database	SILVA	Inhouse database consisting of: Greengenes, SILVA and 16s core bacterial database	RDP tools version 2.12
Filtering	ASVs present at count <1 Comparison of multiple cutoffs: >4% overall >50% per group >50% overall	Presence in at least 70% of samples & >100 OTUs	Minimum of 20 sequence reads
Bioinformatic Pipeline	QIIME2	QIIME2	Geneious Prime Softwares (Geneious Prime 2020.1.2)
Taxonomic lineage assignment	ASVs	OTUs	Neither

Abbreviations: ASV, amplicon sequencing variant; OTU, operational taxonomic unit.