Cited by 192Genomics and Phylogenetic StudiesGut microbiota and healthMicrobial Community Ecology and Physiology

The DOI matches its Crossref record; 24 of the 25 references it cites were found in a registry or an index.

Deriving accurate microbiota profiles from human samples with low bacterial content through post-sequencing processing of Illumina MiSeq data

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Abstract

BACKGROUND: The rapid expansion of 16S rRNA gene sequencing in challenging clinical contexts has resulted in a growing body of literature of variable quality. To a large extent, this is due to a failure to address spurious signal that is characteristic of samples with low levels of bacteria and high levels of non-bacterial DNA. We have developed a workflow based on the paired-end read Illumina MiSeq-based approach, which enables significant improvement in data quality, post-sequencing. We demonstrate the efficacy of this methodology through its application to paediatric upper-respiratory samples from several anatomical sites. RESULTS: A workflow for processing sequence data was developed based on commonly available tools. Data generated from different sample types showed a marked variation in levels of non-bacterial signal and 'contaminant' bacterial reads. Significant differences in the ability of reference databases to accurately assign identity to operational taxonomic units (OTU) were observed. Three OTU-picking strategies were trialled as follows: de novo, open-reference and closed-reference, with open-reference performing substantially better. Relative abundance of OTUs identified as potential reagent contamination showed a strong inverse correlation with amplicon concentration allowing their objective removal. The removal of the spurious signal showed the greatest improvement in sample types typically containing low levels of bacteria and high levels of human DNA. A substantial impact of pre-filtering data and spurious signal removal was demonstrated by principal coordinate and co-occurrence analysis. For example, analysis of taxon co-occurrence in adenoid swab and middle ear fluid samples indicated that failure to remove the spurious signal resulted in the inclusion of six out of eleven bacterial genera that accounted for 80% of similarity between the sample types. CONCLUSIONS: The application of the presented workflow to a set of challenging clinical samples demonstrates its utility in removing the spurious signal from the dataset, allowing clinical insight to be derived from what would otherwise be highly misleading output. While other approaches could potentially achieve similar improvements, the methodology employed here represents an accessible means to exclude the signal from contamination and other artefacts.

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Crossref · 10.1186/s40168-015-0083-8

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Figures

Figure 1 Workflow of bioinformatic and biostatistical analysis.
Figure 1 Workflow of bioinformatic and biostatistical analysis.CC BY · PubMed Central
Figure 2 Proportion of sequence reads removed from adenoid swab compared to adenoid biopsy. (A) Proportion of reads removed by pre-filtering human OTUs in adenoid swab (n = 11) and adenoid biopsies (n = 11). ***P < 0.002, Mann–Whitney test. (B) Relative abundance of sequences identified as artefact in adenoid swab and adenoid biopsies. *P < 0.032, Mann–Whitney test.
Figure 2 Proportion of sequence reads removed from adenoid swab compared to adenoid biopsy. (A) Proportion of reads removed by pre-filtering human OTUs in adenoid swab (n = 11) and adenoid biopsies (n = 11). ***P < 0.002, Mann–Whitney test. (B) Relative abundance of sequences identified as artefact in adenoid swab and adenoid biopsies. *P < 0.032, Mann–Whitney test.CC BY · PubMed Central
Figure 3 Relative abundance of OTUs identified as potential sequencing artefact plotted against amplicon concentration following library preparation. Spearman’s rho (ρ) and significance of correlation are shown.
Figure 3 Relative abundance of OTUs identified as potential sequencing artefact plotted against amplicon concentration following library preparation. Spearman’s rho (ρ) and significance of correlation are shown.CC BY · PubMed Central
Figure 4 Relative abundance of presumed contamination and genuine signal plotted against amplicon concentration. Relative abundance of OTUs of sequencing artefacts (A-C) and non-artefacts (D-F) plotted against amplicon concentration following library preparation. Spearman’s rho (ρ) and significance of correlation are shown.
Figure 4 Relative abundance of presumed contamination and genuine signal plotted against amplicon concentration. Relative abundance of OTUs of sequencing artefacts (A-C) and non-artefacts (D-F) plotted against amplicon concentration following library preparation. Spearman’s rho (ρ) and significance of correlation are shown.CC BY · PubMed Central
Figure 5 Proportion of sequence reads removed by pre-filtration or when identified as contaminants. The proportion of the total number of sequence reads obtained that were removed at the pre-filtering step or after being identified as potential contamination are shown for each of the four sample types. Also shown, the proportion of total sequence reads that were representative of the bacterial signal. Proportions do not sum up to 100% in each sample type as the reads removed as contaminants are shown as a proportion of the filtered reads.
Figure 5 Proportion of sequence reads removed by pre-filtration or when identified as contaminants. The proportion of the total number of sequence reads obtained that were removed at the pre-filtering step or after being identified as potential contamination are shown for each of the four sample types. Also shown, the proportion of total sequence reads that were representative of the bacterial signal. Proportions do not sum up to 100% in each sample type as the reads removed as contaminants are shown as a proportion of the filtered reads.CC BY · PubMed Central
Figure 6 Principal coordinate plots based on a BC similarity matrix of bacterial community sequence data. Distribution of adenoid swabs, middle ear fluid and nasopharyngeal swabs are shown before (A) and after (B) removal of signal derived from contaminants. Panel A is based on 11 adenoid swabs, 13 middle ear fluid and 11 N swabs, with panel B based on 10 adenoid swabs, 11 middle ear fluid and 11 nasopharyngeal swabs.
Figure 6 Principal coordinate plots based on a BC similarity matrix of bacterial community sequence data. Distribution of adenoid swabs, middle ear fluid and nasopharyngeal swabs are shown before (A) and after (B) removal of signal derived from contaminants. Panel A is based on 11 adenoid swabs, 13 middle ear fluid and 11 N swabs, with panel B based on 10 adenoid swabs, 11 middle ear fluid and 11 nasopharyngeal swabs.CC BY · PubMed Central
Figure 7 Co-occurrence plots for genera detected in adenoid swabs, middle ear fluid, and nasopharyngeal swabs. Plots are shown for data before (A) and after (B) removal of the signal derived from contaminants. Genera detected in both adenoid and MEF are highlighted. Note that Achromobacter was not removed based upon spurious distribution. However, following the removal of all contaminant OTUs and rarefaction to 400 reads, the sample with Achromobacter at >1.5% relative abundance was removed due to low sequencing depth. The removal based on spurious distribution of a Rhizobium OTU, detected in both NP and MEF, is also shown.
Figure 7 Co-occurrence plots for genera detected in adenoid swabs, middle ear fluid, and nasopharyngeal swabs. Plots are shown for data before (A) and after (B) removal of the signal derived from contaminants. Genera detected in both adenoid and MEF are highlighted. Note that Achromobacter was not removed based upon spurious distribution. However, following the removal of all contaminant OTUs and rarefaction to 400 reads, the sample with Achromobacter at >1.5% relative abundance was removed due to low sequencing depth. The removal based on spurious distribution of a Rhizobium OTU, detected in both NP and MEF, is also shown.CC BY · PubMed Central

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Research works printed but not linked: 2

  1. The National Center for Biotechnology Information Sequence Read Archive. http://www.ncbi.nlm.nih.gov/sra/ (accessed 011014)
  2. The National Center for Biotechnology Information Basic Local Alignment Search Tool. http://blast.ncbi.nlm.nih.gov/Blast.cgi (accessed 011014)

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Metadata

Authors
Jervis-Bardy, J., Leong, L. E. X., Marri, S., Smith, R. J., Choo, J. M., Smith-Vaughan, H. C., Nosworthy, E., Morris, P. S., O’Leary, S., Rogers, G. B., & Marsh, R. L.
Affiliations
  • Flinders University (AU)
  • South Australian Health and Medical Research Institute (AU)
  • Charles Darwin University (AU)
  • The University of Melbourne (AU)
Corresponding author
Jervis-Bardy, Jake
Venue
Microbiome
Published
2015-05-05
Volume
3
Issue
1
Pages
19-19
ISSN
2049-2618 (ISSN-L)
OpenAlex
W2063276097
Cited by
192
References
25
Citations by year
2026: 3 · 2025: 6 · 2024: 10 · 2023: 20 · 2022: 14 · 2021: 23 · 2020: 25 · 2019: 27 · 2018: 23 · 2017: 20 · 2016: 18 · 2015: 3
FWCI
9.27
Type
journal article
Language
en
Open access
Locations
  • Microbiome (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Minerva Access (University of Melbourne) (submittedVersion, cc-by)
  • Adelaide Research & Scholarship (AR&S) (University of Adelaide) (submittedVersion, cc-by)
  • Griffith Research Online (submittedVersion, cc-by)
Funders
  • Medical Research Council
  • National Health and Medical Research Council (1007641)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Genomics and Phylogenetic Studies
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Gut microbiota and health
  • Physical Sciences › Environmental Science › Ecology › Microbial Community Ecology and Physiology
Keywords
16S rRNA gene sequencing, microbiota profiling, reagent contamination, operational taxonomic units, paired-end reads, middle ear fluid, reference database

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