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Updated: Jul 10, 2026

Laboratory Techniques Used to Maintain and Differentiate Biotypes of Vibrio cholerae Clinical and Environmental Isolates
07:58

Laboratory Techniques Used to Maintain and Differentiate Biotypes of Vibrio cholerae Clinical and Environmental Isolates

Published on: May 30, 2017

A bacteriophage encoding a pathogenicity island, a type-IV pilus and a phage receptor in cholera bacteria

D K Karaolis1, S Somara, D R Maneval

  • 1Center for Vaccine Development, Division of Hospital Epidemiology, University of Maryland School of Medicine, Baltimore 21201, USA. karaolis@umaryland.edu

Nature
|June 9, 1999
PubMed

Insights

Pathogenicity islands, crucial for bacterial virulence, were previously poorly understood. This study reveals the V. cholerae pathogenicity island (VPI) is a bacteriophage (VPIphi), detailing its transfer and role in disease.

Area of Science:

  • Microbiology
  • Virology
  • Genetics

Background:

  • Pathogenicity islands (PAIs) are large gene clusters encoding virulence factors in many bacterial pathogens.
  • The origins and transfer mechanisms of PAIs remain largely unknown.
  • Vibrio cholerae utilizes a PAI (VPI) encoding a colonization factor and CTXphi receptor.

Purpose of the Study:

  • To elucidate the origin and transfer mechanism of the V. cholerae pathogenicity island (VPI).
  • To investigate the nature of the VPI and its relationship with other mobile genetic elements.
  • To understand the virus-virus interaction in bacterial pathogenicity.

Main Methods:

  • Genomic analysis to identify the VPI as a bacteriophage genome.
  • Bacterial conjugation experiments to demonstrate VPI transfer between V. cholerae strains.
  • Protein analysis to identify VPI components.

Main Results:

  • The VPI pathogenicity island was identified as the genome of a filamentous bacteriophage, VPIphi.
  • VPIphi is transferable between V. cholerae strains.
  • The TcpA subunit of the toxin-coregulated pilus is a VPIphi coat protein.
  • This represents the first description of a phage encoding a receptor for another phage.

Conclusions:

  • The VPI pathogenicity island is a bacteriophage (VPIphi) capable of horizontal gene transfer.
  • VPIphi plays a critical role in Vibrio cholerae pathogenicity by mediating colonization and phage receptor functions.
  • This study reveals a novel virus-virus interaction essential for bacterial virulence.

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