The cryptic plasmid improves chlamydia fitness in different regions of the gastrointestinal tract

Jingyue Ma, Conghui He, Zhi Huo, Ying Xu, Bernard Arulanandam, Quanzhong Liu, Guangming Zhong

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


The cryptic plasmid is important for chlamydial colonization in the gastrointestinal tract. We used a combination of intragastric, intrajejunal, and intracolon inoculations to reveal the impact of the plasmid on chlamydial colonization in distinct regions of gastrointestinal tract. Following an intragastric inoculation, the plasmid significantly improved chlamydial colonization. At the tissue level, plasmidpositive Chlamydia produced infectious progenies throughout gastrointestinal tract. However, to our surprise, plasmid-deficient Chlamydia failed to produce infectious progenies in small intestine, although infectious progenies were eventually detected in large intestine, indicating a critical role of the plasmid in chlamydial differentiation into infectious particles in small intestine. The noninfectious status may represent persistent infection, since Chlamydia genomes proliferated in the same tissues. Following an intrajejunal inoculation that bypasses the gastric barrier, plasmiddeficient Chlamydia produced infectious progenies in small intestine but was 530-fold less infectious than plasmid-positive Chlamydia, suggesting that (i) the noninfectious status developed after intragastric inoculation might be induced by a combination of gastric and intestinal effectors and (ii) chlamydial colonization in small intestine was highly dependent on plasmid. Finally, following an intracolon inoculation, the dependence of chlamydial colonization on plasmid increased over time. Thus, we have demonstrated that the plasmid may be able to improve chlamydial fitness in different gut regions via different mechanisms, which has laid a foundation to further reveal the specific mechanisms.

Original languageEnglish (US)
Article numbere00860-19
JournalInfection and immunity
Issue number3
StatePublished - Mar 1 2020


  • Chlamydia
  • Chlamydia muridarum
  • GI tract colonization
  • Gastrointestinal tract
  • Persistence
  • Plasmid

ASJC Scopus subject areas

  • Infectious Diseases
  • Parasitology
  • Microbiology
  • Immunology


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