Protochlamydia phocaeensis sp. nov., a new Chlamydiales species with host dependent replication cycle

Microbes Infect. 2017 Jun;19(6):343-350. doi: 10.1016/j.micinf.2017.02.003. Epub 2017 Mar 7.


Chlamydiae are pathogenic and symbiotic bacteria, which form an important part of amoeba-associated microorganisms. In this paper, we report the isolation, developmental cycle and genome analysis of Protochlamydia phocaeensis sp. nov., an obligate intracellular parasite with a large host spectrum, able to infect Acanthamoeba castellanii, Acanthamoeba polyphaga, and Vermamoeba vermiformis. The genome size is 3,424,182 bp with a GC content of 42%. This bacterium displayed a particular developmental cycle depending on the infected host. The P. phocaeensis showed typical inclusion vacuoles in A. castellanii, while these were absent in V. vermiformis. Since "Chlamydiae-amoebae" interactions are supposed to depend on the chlamydial species, our findings speculate that variations in the developmental cycle of certain Chlamydiae are also host dependent.

Keywords: Chlamydiae; Host spectrum; Inclusion vacuoles; Protochlamydia phocaeensis; Vermamoeba vermiformis.

MeSH terms

  • Acanthamoeba / microbiology
  • Acanthamoeba castellanii / microbiology
  • Chlamydiales / classification
  • Chlamydiales / genetics
  • Chlamydiales / isolation & purification*
  • DNA, Bacterial / genetics
  • Genome, Bacterial*
  • Host-Pathogen Interactions*
  • In Situ Hybridization, Fluorescence
  • Lobosea / microbiology
  • Microscopy, Electron, Transmission
  • RNA, Ribosomal, 16S / genetics
  • RNA, Ribosomal, 23S / genetics


  • DNA, Bacterial
  • RNA, Ribosomal, 16S
  • RNA, Ribosomal, 23S