Identification of Plasmid-Free Chlamydia muridarum Organisms Using a Pgp3 Detection-Based Immunofluorescence Assay.

Chlamydia possesses a conserved 7.5 kb plasmid that is known to play an important role in chlamydial pathogenesis, since some chlamydial organisms lacking the plasmid are attenuated. The chlamydial transformation system developed recently required the use of plasmid-free organisms.