Chlamydia Infection

• Chlamydia is a common sexually transmitted infection affecting millions annually, often without symptoms.

How It Spreads

• Vaginal, anal, and oral sex can spread chlamydia.
• An infected mother can transmit it to her baby during vaginal childbirth.

Untreated Chlamydia

• Pelvic inflammatory disease (PID) can result if chlamydia is left untreated
• PID can cause chronic pain and permanent fertility damage.

Asymptomatic Infections

• 75% of infected women don't experience symptoms.
• 50% of infected men don't experience symptoms.

Gram-Negative Structure

• Chlamydia has a Gram-negative structure but lacks peptidoglycan
• It has Lipopolysaccharide (LPS).

Diagnosis

• Endocervical swabs are obtained and used to inoculate McCoy cells for lab examination.
• Cells are stained to observe inclusions after incubation.

Obligate Intracellular Bacteria

• Chlamydia are obligate intracellular bacteria, requiring a host

Dimorphic Forms

• Elementary bodies cause infection are small (300-350 nm).

• Reticulate bodies are where replication happens, they are large (800-1000 nm).

Comparison to Bacteria and Viruses

• Chlamydiae are microorganisms with characteristics intermediate between bacteria and viruses.

• The organisms have no cell wall but present a like Gram negative cell wall.

• Nucleic acid is RNA & DNA for both chlamydia and bacteria, whereas RNA or DNA in viruses

• Antibiotic sensitivity occurs for both chlamydia and bacteria, whereas resistance in observed I viruses.

Life Cycle

• EB makes contact with host cell plasma membrane and is taken up by endocytosis/phagocytosis.
• EB transforms into a reticulate body (RB) where RB divides and replicates repeatedly by binary fission
• Replication forms inclusion bodies; RBs transition back into EBs, and the cell lysis

Unique Qualities Describing Factors

• Shared group antigens include heat-stable lipopolysaccharides.
• Species-specific antigens consist of outer membrane proteins.
• Outer membrane proteins cause damage in trachoma is due to repeated infections.

Chlamydia trachomatis: Ocular Infections (Trachoma)

• Serotypes A, B, and C are often found in hot climates.
• Lacrimation, muco-purulent discharge and lymphoid follicles in conjunctiva occur
• Repeated infections can lead to blindness
• Mechanical abrasion from in-turned eyelids leads to scarring of the conjunctiva
• Corneal ulceration and pannus formation in the cornea are a consequence

Inclusion Conjunctivitis (Paratrachoma)

• Serotypes D-K causes follicular conjunctivitis with muco-purulent discharge .
• Disease is milder, resolving itself but rarely causes blindness.
• Occurs in sexually active adults (18-30.
• It often the result of genital infection and spread to the eyes.

Neonatal Inclusion Conjunctivitis

• Characterized by muco-purulent discharge and swelling of the eyelids and orbit
• Pneumonia occurs may occur in the babies
• It is from babies born to mothers with genital infection.
• Without treatment, it leads to conjunctival scarring and corneal vascularization.

Respiratory Infections (Infant Pneumonia)

• Acquired from mother during birth with conjunctival infection leading to pneumonia
• Infants develop rhinitis and cough, but remain afebrile.

Genital Infections

• Infections in males are symptomatic, with serotypes D-K
• Dual infections with N. gonorrhea can occur in males
• 50% of non-gonococcal urethritis (NGU) is caused by C. trachomatis.
• The infection in females are asymptomatic with serotypes D-K
• Urethral discharge may occur in males whereas Mucopurulent discharge in the females.

Complications

• 1ry lesion at the infection site are small and with any pain
• Can spread to lymph nodes, with inflammation & swelling.
• The disease causes genital elephantiasis for both males and females
• Manifestation in males are the progression of epididymitis.
• Chronic infections leads to infertility.
• Untreated in females develop may develop into chronic ulcerative disease

Laboratory Diagnostics

• Clinical diagnosis through urethral or cervical scrapings and conjunctival discharge.
• Microscopy and immunofluorescence or Giemsa staining used (doesn't stain on Gram stain)
• Detection by PCR has the best results, but highly priced
• Presence of antibodies does not always coincide with current infection- must assess if rising

Treatment

• Adults with Tetracycline or Doxycycline
• Erythromycin or Azithromycin is used for babies or children
• Females with chronic or ascending infections require treatment for 3 weeks .

C.psittaci Species

• Transmitted from birds (parrots) to humans through inhalation of dried secretions.
• Rare to transmit from Person-to-person
• Mild flu-like symptoms can occur or can cause severe disease with pneumonia
• CNS involvement may occur
• Treated through Erythromycin or tetracycline.

C.pneumoniae Species

• Also known as TWAR agent (Taiwan acute respiratory agent), the transmission through person-to-person
• Respiratory tract disease can occur with pharyngitis, laryngitis, or bronchitis
• Staining and culture difficulty are observed in laboratory diagnosis & treated through tetracycline.

Summary of Infections

• Chlamydia causes trachoma, inclusion conjunctivitis, and pneumonia
• C. pneumoniae causes pneumonia
• C. psittaci causes psittacosis.