Virulence Factor Databases
One-Sentence Definition
Virulence factor databases catalog genes and systems that contribute to pathogenicity, allowing sequence-based detection of virulence potential in microbial genomes.
Simple Explanation
Like AMR databases, but for weapons instead of shields: toxins, adhesins, secretion systems, capsule loci.
Detailed Scientific Explanation
| Resource | Focus |
|---|---|
| VFDB | Broad curated virulence factors across pathogens |
| Victors | Host–pathogen virulence data |
| PATRIC/BV-BRC | Integrated genomics + virulence/AMR views |
| Species schemes | Kleborate (Klebsiella virulence/AMR), E. coli pathotyping (VirulenceFinder) |
Categories detected: adhesins, invasins, toxins, siderophores, Capsule loci, secretion systems (T3SS/T4SS/T6SS), immune-evasion factors.
Caveats: presence ≠ expression; virulence is host-context dependent; database bias toward well-studied pathogens.
Mechanism
Homology search of annotated proteins/genes against curated virulence references, with identity/coverage thresholds — same engine logic as AMR Gene Databases.
Clinical Importance
- Explains unusual severity (e.g., hypervirulent Klebsiella pneumoniae, PVL-positive Staphylococcus aureus)
- Rarely changes immediate therapy; informs epidemiology and outbreak severity assessment
Research Importance
- Genotype–phenotype studies; candidate targets for Protein Design for Antimicrobials
Diagnostic Relevance
- Reference/public-health labs more than routine diagnostics
AMR Relevance
- Convergence of virulence + resistance plasmids is a major surveillance concern
Related MOCs
Active Recall Questions
- Name three categories of virulence factors detectable from sequence.
- Why is “gene present” insufficient to predict severity?
- Which convergence worries surveillance programs?