2017/2018- Essay 3

Question 1

Title

Describe the infection cycle of **Chlamydia trachomatis, **considering the roles of elementary and reticulate bodies.

Answer 1

Title: The Infection Cycle of Chlamydia trachomatis: Roles of Elementary and Reticulate Bodies

Question 2

What is it? Infection cycle

Introduction

Describe the infection cycle of **Chlamydia trachomatis, **considering the roles of elementary and reticulate bodies.

Answer 2

What is it?
- gram-negative obligate intracellular bacterial pathogen
- Causes sexually transmitted infections (STIs)
- Genital tract infections
- Urethritis
- Cervicitis
- Pelvic inflammatory disease

Infection cycle
-2 distinct developmntal forms
1. Elementary bodies (EBs)
2. Reticulate bodies (RBs)

Question 3

How does the infection cycle start?

Paragraph 1

Describe the infection cycle of **Chlamydia trachomatis, **considering the roles of elementary and retifculate bodies.

Answer 3

Attachment and Entry
- EBs are infectious form
- attachment of EBs to host cell
- mediated- EB surface proteins (chlamidial adhesins) with host cell receptors
- Attached - EB internalised - Uptake endocytosis-> membrane bound vacuole (INCLUSION vacuole)

Transition to the Reticulate bodies (RBs)
* Inside host cell-> transform to metabolically active non infections reticulate bodies (RBs)
* Due to environmental triggers: decrease in pH, proteases in host cell
* RBs replicate by binary fission
* Uses host cell metabolic machinery to support growth

Intracellular Replication
* RBs multiply within inclusion vacuole
* large number of progeny
* Inclusion vacuole protects developing RBs from host immune system
* Sheltered environ-> bacteria thrives

Question 4

Inclusion , RB

Paragraph 2

Describe the infection cycle of **Chlamydia trachomatis, **considering the roles of elementary and retifculate bodies.

Answer 4

Reversion to Elementary bodies (EBs)
* RBs continue to replicate
* Portion undergo reverse transformation ->EBs
* Process: Reversion
* Why: chlamydial population reaches critical mass within inclusion vacuole
* New EBs accumulate within inclusion

Cell lysis and release
* vacuole filled with EBs
* Lysis releases infectious EBs -> extracellular environment
* Release and intitiate new infection

Host immune response and tissue damage
* Triggers innate and adaptive immune responses
* attempts to control infection
* >inflammation and immune cell recruitment to site of infection
* Intracellular natuire of Chlamydia trachomatis evade certain aspects of immune response
* Leads to persistent chronic infections
* Results in inflammatory response, contribute to development of clinical maifestations associated with Chlamydial infections.

Question 5

Conclusion- Paragraph 6

Describe the infection cycle of **Chlamydia trachomatis, **considering the roles of elementary and retifculate bodies.

Answer 5

• infection cycle well coordinated and intricuate process
• Transition developmental forms EBS and RBs
• Chlamydia Trqchomatis switch between forms allowinf survival within host cells

Importance
- Role of EBs and RBs
- targeted interventions and therapeutic approaches
- Public health initiatives, promoting awarenss, routine screening, early treatment - role in reducing prevalence and impact of Chlamydia trachomatis infections globally.