RFPlasmid: predicting plasmid sequences from short-read assembly data using machine learning

Linda van der Graaf-van Bloois1,2, Jaap A Wagenaar1,2,3, Aldert L Zomer1,2

  • 1Faculty of Veterinary Medicine, Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, The Netherlands.

Microbial Genomics
|November 30, 2021
PubMed

Insights

Identifying antimicrobial-resistance (AMR) genes on plasmids versus chromosomes is crucial. RFPlasmid is a new tool that accurately distinguishes plasmid and chromosomal DNA in bacterial genomes, aiding molecular epidemiology and risk assessment.

Area of Science:

  • Microbiology
  • Genomics
  • Bioinformatics

Background:

  • Antimicrobial-resistance (AMR) genes are frequently located on bacterial plasmids, facilitating their spread.
  • Distinguishing between plasmid-borne and chromosomal AMR genes is vital for molecular epidemiology and risk assessment.
  • Draft bacterial genome assemblies pose challenges in accurately differentiating plasmid and chromosomal contigs.

Purpose of the Study:

  • To develop a novel computational tool, RFPlasmid, for accurate prediction of plasmid versus chromosomal contigs in bacterial genomes.
  • To overcome limitations of existing methods that rely on single features and struggle with large, single-copy plasmids.

Main Methods:

  • RFPlasmid utilizes a combination of features, including k-mer composition and curated databases of plasmid and chromosomal marker proteins.
  • The tool incorporates predictive models for 17 specific bacterial taxa.
  • A taxon-agnostic model is available for metagenomic assemblies and unsupported organisms.

Main Results:

  • RFPlasmid demonstrates improved accuracy in distinguishing plasmid and chromosomal contigs compared to single-feature methods.
  • The tool effectively handles complex genomic data, including large single-copy plasmids.
  • Validated models for key bacterial species like *Campylobacter*, *Escherichia coli*, and *Salmonella*.

Conclusions:

  • RFPlasmid provides a robust and versatile solution for classifying contigs from draft bacterial genomes.
  • Accurate plasmid/chromosome discrimination enhances AMR surveillance, molecular epidemiology, and risk assessment.
  • The tool is accessible as a standalone application and through a web interface.

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