A Plasmid-Cured Chlamydia Muridarum Strain Displays Altered Plaque Morphology and Reduced Infectivity in Cell Culture

Microbiology. 2006 Jun;152(Pt 6):1601-1607. doi: 10.1099/mic.0.28658-0.


A highly conserved cryptic plasmid is present in Chlamydia trachomatis yet naturally occurring plasmid-deficient isolates are very rare. This paper describes the isolation and characterization of a plasmid-deficient strain of C. muridarum, using novobiocin as a curing agent. Plasmid-deficient derivatives of C. muridarum strain Nigg were generated at high efficiencies (4-30%). Phenotypic characterization revealed that the cured derivative was unable to accumulate glycogen within intracytoplasmic inclusions. In addition, this strain formed small plaques at a reduced efficiency compared to the wild-type parent.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacology*
  • Cell Line
  • Centrifugation
  • Chlamydia muridarum / drug effects
  • Chlamydia muridarum / genetics
  • Chlamydia muridarum / growth & development*
  • Chlamydia muridarum / pathogenicity*
  • Glycogen / metabolism
  • Mice
  • Novobiocin / pharmacology*
  • Plasmids / genetics*
  • Polymerase Chain Reaction


  • Anti-Bacterial Agents
  • Novobiocin
  • Glycogen