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A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
07:10

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues

Published on: February 19, 2019

Does the possession of virulence factor genes mean that those genes will be active?

Stephen C Edberg1

  • 1Laboratory Medicine and Internal Medicine and Chemical Engineering, Yale University School of Medicine, 333 Cedar Street, PO Box 208035, New Haven, CT 06520-8035, USA. stephen.edberg@yale.edu

Journal of Water and Health
|September 1, 2009
PubMed

Insights

Most ingested microbes do not survive in the human host, but some establish a resident flora. Virulence factors are needed for pathogens, but not all microbial factors, like VFAR, indicate disease risk.

Area of Science:

  • Microbiology
  • Human Physiology
  • Gastroenterology

Background:

  • The human host interacts with numerous ingested microbes daily.
  • Most microbes are eliminated by host defenses like stomach acid and bile.
  • A stable, resident normal flora, primarily bacteria, is established early in life on mucosal surfaces.

Purpose of the Study:

  • To explore the interactions between ingested microbes and the human host.
  • To differentiate between microbes that colonize the host and those that cause disease.
  • To understand the role of virulence factors in microbial pathogenesis.

Main Methods:

  • Review of existing literature on host-microbe interactions.
  • Analysis of microbial survival mechanisms in the gastrointestinal tract.
  • Identification of known microbial virulence factors, including enzymes.

Main Results:

  • The majority of ingested microbes have transient interactions with the host.
  • Resident normal flora microbes possess specific receptors for gastrointestinal tract colonization.
  • Pathogenic microbes require specific virulence factors to cause disease, some of which are known enzymes like protease and lipase.
  • VFAR (Virulence Factor Associated Resistance) may not be linked to human disease.

Conclusions:

  • Microbial colonization of the human host is a selective process.
  • Virulence factors are critical for microbial pathogenicity.
  • The presence or absence of VFAR has no public health significance.

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