Chlamydia trachomatis has a unique biphasic life cycle. The elementary body (EB) and reticulate body (RB) differ in that the EB:

• A Is the metabolically active form that replicates by binary fission inside host cell inclusions
• B Is the infectious, metabolically inert form with a rigid cell wall due to outer membrane protein complex cross-linking, capable of extracellular survival ✓
• C Has a fragile cell wall and cannot survive outside host cells but is highly replicative
• D Exclusively infects epithelial cells of the conjunctiva, unlike RBs which infect other tissues

Explanation

The Chlamydia life cycle involves two forms: the elementary body (EB) is the infectious, extracellularly stable form with a compact, electron-dense nucleoid and outer membrane proteins (OmpA, Pmps) stabilized by disulfide bonds that confer cell-wall rigidity and environmental resistance. EBs attach to host epithelial cells and are internalized. Inside the endosome (inclusion), EBs differentiate into the reticulate body (RB) — the large, metabolically active, intracellularly replicating form. RBs divide by binary fission, then convert back to EBs for release.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.