The document discusses the strengths, weaknesses, opportunities, and threats (SWOT) of using whole genome sequencing (WGS) for surveillance and diagnostics of zoonotic bacteria. It provides a case study of using WGS to track the nosocomial transmission of Pseudomonas aeruginosa between patients and the hospital water supply. WGS was able to identify transmission routes and microevolution of the bacteria with single nucleotide resolution. However, challenges include the need for robust and standardized analysis methods as well as experimental design considerations. Overall, WGS provides opportunities for improved outbreak tracking, classification, and diagnostics if its strengths are leveraged and weaknesses addressed.
1. Sequencing and Beyond?
Risks and SWOT for
sequencing-led surveillance
and diagnostics of zoonotic
bacteria
Leighton Pritchard1;2;3
1Information and Computational Sciences,
2Centre for Human and Animal Pathogens in the Environment,
3Dundee Eector Consortium,
The James Hutton Institute, Invergowrie, Dundee, Scotland, DD2 5DA
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3. Table of Contents
SWOT analysis
Case Study
Nosocomial P.aeruginosa acquisition
Strengths
Weaknesses
Opportunities
Threats
Acknowledgements
Without Whom. . .
4. What is SWOT?
A generic structured planning/categorisation method
Identify the objective, and identify internal and external factors
that can help or harm reaching that objective.
Strengths: characteristics of sequencing approaches that may
be helpful
Weaknesses: characteristics of sequencing approaches that
might be harmful
Opportunities: external elements that could be helpful
Threats: external elements that may be harmful
Its purpose is to guide strategies that might help achieve objectives.
6. Table of Contents
SWOT analysis
Case Study
Nosocomial P.aeruginosa acquisition
Strengths
Weaknesses
Opportunities
Threats
Acknowledgements
Without Whom. . .
7. P.aeruginosa nosocomial acquisitiona
a
Quick et al. (2014) BMJ Open 4: e006278. doi:10.1136/bmjopen-2014-006278
Motivation
Nosocomial water transmission of P.aeruginosa an urgent concern
8. P.aeruginosa nosocomial acquisitiona
a
Quick et al. (2014) BMJ Open 4: e006278. doi:10.1136/bmjopen-2014-006278
Motivation
Nosocomial water transmission of P.aeruginosa an urgent concern
Setup
Burns patients (30) screened for P.aeruginosa on admission
Samples taken from patients and environment
All P.aeruginosa isolates (141) WGS sequenced
9. P.aeruginosa nosocomial acquisitiona
a
Quick et al. (2014) BMJ Open 4: e006278. doi:10.1136/bmjopen-2014-006278
Motivation
Nosocomial water transmission of P.aeruginosa an urgent concern
Setup
Burns patients (30) screened for P.aeruginosa on admission
Samples taken from patients and environment
All P.aeruginosa isolates (141) WGS sequenced
Outcome
Clustering of isolates by room and outlet
Three patient isolates identical to water isolates from same room
Bio
12. P.aeruginosa nosocomial acquisitiona
a
Quick et al. (2014) BMJ Open 4: e006278. doi:10.1136/bmjopen-2014-006278
Methods
Illumina MiSeq WGS of 141 isolates
Metagenomic sequencing of bio
13. lm
Simulated sequencing of 55 published P. aeruginosa
BWA mapping against PAO1 reference genome
SNPs called with SAMtools VarScan
ML reconstruction with FastTree
De novo assembly with Velvet for MLST prediction
Sequences and bioinformatic methods shared online:
http://www.github.com/joshquick/snp calling scripts
16. P.aeruginosa nosocomial acquisitiona
a
Quick et al. (2014) BMJ Open 4: e006278. doi:10.1136/bmjopen-2014-006278
Strengths
A P. aeruginosa source could be tracked by WGS
Insights into transmission: water to patient a likely route
Sensitivity - identi
18. P.aeruginosa nosocomial acquisitiona
a
Quick et al. (2014) BMJ Open 4: e006278. doi:10.1136/bmjopen-2014-006278
Strengths
A P. aeruginosa source could be tracked by WGS
Insights into transmission: water to patient a likely route
Sensitivity - identi
19. es microevolution
Limitations
Small sample size: 5/30 patients infected, gave 55/141 isolates
Not clear that causal inferences are general
300-day sampling, not real-time crisis analysis
Good existing reference genome set for this bacterium
Sequencing cost: $8k; Sta cost: $15k; (infrastructure $?)
20. Table of Contents
SWOT analysis
Case Study
Nosocomial P.aeruginosa acquisition
Strengths
Weaknesses
Opportunities
Threats
Acknowledgements
Without Whom. . .
21. Strength: Illumina
Illumina sequencing is a stable, widespread technology
Low price: $50 per WGS bacterial genome
Robust software for assembly/mapping
Single assay pipeline for multiple species
Promise of (near) real-time genotyping and surveillance
22. Strength: Nature of information
(Almost) complete genome sequence information with WGS
Extremely sensitive: whole-genomes at single SNP/indel
resolution
Enables tracing of microevolution
Data is digital, and in
23. nitely sharable
Reference repositories for data: ENA/SNA, NCBI etc.
Can build on public sequence data
24. Strength: Active RD area
Technology is still moving forward: good things will get better
Nanopore promises cheap, long reads
Assembly/SNP calling tools can improve
New techniques, technologies, software, : : :
Active
26. Table of Contents
SWOT analysis
Case Study
Nosocomial P.aeruginosa acquisition
Strengths
Weaknesses
Opportunities
Threats
Acknowledgements
Without Whom. . .
27. Weakness: New technologies
New technologies may not be robust or reliable
Readily available only in more developed nations; in labs, not
farms/factories?
New sequencing technologies still to be proven (Nanopore)
Lack of plug-and-play analysis solutions: requires
statistical/computing/biological expertise
Plethora of assembly/mapping tools: results and quality vary
Stability of results/analysis
28. Weakness: Nature of information
Data integrity, availability critical for success
Siloing of data (no public submission) can happen
Inaccurate or incorrect reference/public data
Inadequate, incorrect or absent metadata (new
ontologies?)
Unstable results between software/technology versions
Reproducibility of analyses
Genome sequence does not generally predict phenotype
32. cation of appropriate metadata (or not)
Sample deeply enough for sucient power (or not)
WGS vs metagenomics
colonies vs communities
whole genomes vs identi
34. Table of Contents
SWOT analysis
Case Study
Nosocomial P.aeruginosa acquisition
Strengths
Weaknesses
Opportunities
Threats
Acknowledgements
Without Whom. . .
41. cation/diagnostics
Comprehensive sequence data could be highly in
uential
High-resolution tracing of outbreaks/contamination/transfer
Combine with system-scale understanding of transport/trade
43. cation/diagnostics
Comprehensive sequence data could be highly in
uential
High-resolution tracing of outbreaks/contamination/transfer
Combine with system-scale understanding of transport/trade
Pangenome-based view of bacteria
Improved taxonomic (and phenotypic?) classi
58. Diagnostics design
Validate against known, unseen examples
Successful at species level in Dickeya1, sub-serotype level in E. coli 2
targets
classication
o-targets
V
IV
III
II
I
primer sets validation gels
I
II
III
IV
V
III IV V +ve -ve
III IV V +ve -ve
III IV V +ve -ve
III IV V +ve -ve
II
V
I
III
1
Pritchard et al. (2013) Plant Path. 62: 587-596. doi:10.1111/j.1365-3059.2012.02678.x
2
Pritchard et al. (2012) PLoS One 7: e34498. doi:10.1371/journal.pone.0034498
59. Diagnostics design
Distinguish at species level in Dickeya3, sub-serotype level in E.
coli 4
3
Pritchard et al. (2013) Plant Path. 62: 587-596. doi:10.1111/j.1365-3059.2012.02678.x
4
Pritchard et al. (2012) PLoS One 7: e34498. doi:10.1371/journal.pone.0034498
60. Table of Contents
SWOT analysis
Case Study
Nosocomial P.aeruginosa acquisition
Strengths
Weaknesses
Opportunities
Threats
Acknowledgements
Without Whom. . .
62. nancially
Whose responsibility is it?
How to ensure funding continuity?
Centralisation vs federation/distribution
63. Threats: Data Management
Having lots of data brings its own problems
Do analyses scale from 10s to 100s to 1000s to 10000s of
sequences? (Where do we do the computing?)
Metadata/data accuracy and provenance
Data standards (minimum information)
Common analytical standards
Timely collection/generation/release in a crisis
64. Scaling
Moving from 30 genome to 1000 genome pairwise comparisons
New algorithms, storage and visualisation tools required
65. Threats: Data Legalities
Who owns what?
Who owns public data? (and who owns the results of
analysis?)
Legal/
70. c skills
New algorithms and techniques for scale
New visualisation and other software tools
Tools/interfaces for usability
Data curators are extremely important!
Is there a skills shortage? Industry better-paid?
Old guard may not appreciate these needs
[employer] isn't interested in an equation as an academic
exercise.
You [: : :] might want to do some [computing] thing that's [...]
special, but we're not interested.
71. Table of Contents
SWOT analysis
Case Study
Nosocomial P.aeruginosa acquisition
Strengths
Weaknesses
Opportunities
Threats
Acknowledgements
Without Whom. . .
72. Acknowledgements
James Hutton Institute
Nicola Holden
Fiona Brennan
Sonia Humphris
Ian Toth
Emma Campbell
University of Aberdeen
Ken Forbes
Norval Strachan
SASA
Gerry Saddler
FERA
Valerie Bertrand
John Elphinstone
Neil Parkinson
University of Munster
Martina Bielaszewska
Helge Karch
GitHub
Benjamin Leopold
Michael Robeson
73. Licence: CC-BY-SA
By: Leighton Pritchard
This presentation is licensed under the Creative Commons
Attribution ShareAlike license
https://creativecommons.org/licenses/by-sa/4.0/