The intracellular pathogen concept

Arturo Casadevall, Ferric C. Fang

Research output: Contribution to journalReview articlepeer-review

3 Scopus citations


The intracellular pathogen concept classifies pathogenic microbes on the basis of their site of replication and dependence on host cells. This concept played a fundamental role in establishing the field of cellular microbiology, founded in part by Dr. Pascale Cossart, whose seminal contributions are honored in this issue of Molecular Microbiology. The recognition that microbes can access and replicate in privileged compartments within host cells has led to many new and fruitful lines of investigation into the biology of the cell and mechanisms of cell-mediated immunity. However, like any scientific concept, the intracellular pathogen concept can become a dogma that constrains thinking and oversimplifies complex and dynamic host–pathogen interactions. Growing evidence has blurred the distinction between “intracellular” and “extracellular” pathogens and demonstrated that many pathogens can exist both within and outside of cells. Although the intracellular pathogen concept remains useful, it should not be viewed as a rigid classification of pathogenic microbes, which exhibit remarkable variation and complexity in their behavior in the host.

Original languageEnglish (US)
Pages (from-to)541-545
Number of pages5
JournalMolecular Microbiology
Issue number3
StatePublished - Mar 1 2020

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology


Dive into the research topics of 'The intracellular pathogen concept'. Together they form a unique fingerprint.

Cite this