Parachlamydiaceae: potential emerging pathogens

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Updated: Oct 1, 2026

Discovery of New Intracellular Pathogens by Amoebal Coculture and Amoebal Enrichment Approaches
09:04

Discovery of New Intracellular Pathogens by Amoebal Coculture and Amoebal Enrichment Approaches

Published on: October 27, 2013

Gilbert Greub1, Didier Raoult

  • 1Unité des Rickettsies, Université de la Méditerranée, Marseille, France.

Emerging Infectious Diseases
|May 25, 2002
PubMed

Insights

Parachlamydiaceae, bacteria that infect amoebae, may be pathogenic. Evidence suggests these bacteria, similar to Chlamydia pneumoniae, could cause respiratory illnesses like pneumonia in humans.

Area of Science:

  • Microbiology
  • Pathogen Discovery
  • Molecular Biology

Background:

  • Parachlamydiaceae are amoeba-infecting bacteria.
  • They share characteristics with Chlamydiaceae, including replication cycles and ribosomal RNA gene homology.
  • Intra-amoebal growth can enhance bacterial virulence.

Purpose of the Study:

  • To evaluate the potential pathogenicity of Parachlamydiaceae.
  • To explore the link between amoeba-infecting bacteria and human respiratory diseases.

Main Methods:

  • Comparative analysis of ribosomal RNA gene homology.
  • Review of existing evidence on Chlamydiales pathogenicity.
  • Identification of bacterial 16S rRNA gene sequences in clinical samples.

Main Results:

  • Parachlamydiaceae exhibit 80-90% ribosomal RNA gene homology with Chlamydiaceae.
  • Chlamydia pneumoniae infects amoebae and causes pneumonia.
  • Simkania negevensis, related to Parachlamydiaceae, causes human respiratory infections.
  • A Parachlamydiaceae 16S rRNA gene sequence was found in bronchoalveolar lavage.

Conclusions:

  • Parachlamydiaceae possess characteristics suggesting pathogenic potential.
  • The presence of Parachlamydiaceae DNA in respiratory samples indicates a possible role in human lung infections.

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