Chlamydia

Obligate intracellular bacterium

What type pf organism is Chlamydia?

Chlamydia

was once regarded as a virus, needing a host cell to survive and multiply

An endotoxin-like lipopolysaccharide antigen

What kind of antigen does Chlamydia produce?

Chlamydia is intracellular, while Mycoplasma is extracellular

How does Chlamydia differ from Mycoplasma?

They cannot survive in the extracellular environment

What is a defining trait of obligate intracellular organisms like Chlamydia?

• Obligate intracellular organisms

• Possess a cell wall but lacks peptidoglycan layer

• Produces endotoxin-like lipopolysaccharide antigen

General characteristics of Chlamydia

Chlamydiae have a cell wall (without peptidoglycan), while Mycoplasmas are cell wall-deficient.

What distinguishes Chlamydiae from Mycoplasmas regarding their cell wall?

The presence of a cell wall that lacks a peptidoglycan layer.

What unique structural feature is found only in Chlamydiae organisms?

It mimics the endotoxin of gram-negative bacteria, allowing the immune system to recognize and combat the infection.

How does Chlamydia’s lipopolysaccharide antigen help in immune detection?

Epithelial cells

What type of cells do Chlamydiae organisms specifically infect?

Tropism to epithelial cells

What is the term used to describe Chlamydia's preference for epithelial cells?

A unique intracellular life cycle within epithelial cells.

What type of life cycle do Chlamydiae organisms undergo?

Because it occurs entirely inside the host's epithelial cells.

Why is Chlamydia's life cycle considered unique?

• Elementary body

• Reticulate Body

• Inclusion Body

Three different phases that Chlamydiae organisms develop within the epithelial cells

Elementary Body

Is the infective stage ; metabolically inactive (not capable of replication)

Reticulate Body

Second stage of the life cycle; metabolically active (replicative stage) ; non-infectious

Inclusion Body

Third stage of the life cycle ; not infectious ; not metabolically active ; diagnostic stage

0.2 – 0.3 µm

What is the size of the elementary body?

Approximately 1 µm

What is the size of the reticulate body?

Elementary body

Which form in the life cycle is resistant to trypsin digestion?

Reticulate body

Which form in the life cycle is sensitive to trypsin digestion?

Reticulate body

Which form has more projections and rosettes?

Elementary body

Which form has fewer projections and rosettes?

Elementary bodies attach to the surface of epithelial cells

What is the first step of Chlamydiae infection (initial infection) in epithelial cells?

They release substances from the cytoplasm to destroy the attached elementary bodies.

What do epithelial cells do in response to the attachment of elementary bodies?

They send signals that stimulate lysosomal enzymes inside the epithelial cell.

How do elementary bodies respond to the epithelial cell’s defense?

Endocytosis

What process allows the epithelial cell to ingest the elementary body?

Phagosome

A capsule-like or envelope-like structure that protects the elementary body after endocytosis

It tricks the epithelial cell into internalizing the pathogen, allowing infection to proceed

What is the significance of the decoy signal sent by elementary bodies?

12 hours after initial infection

The elementary bodies transform into reticulate bodies, which are metabolically active and start to multiply.

24 hours after initial infection

The reticulate bodies cluster together and are encased in a larger phagosome.

48 hours after initial infection

Some of the reticulate bodies reorganize back into elementary bodies, resulting in a larger phagosome containing both reticulate and elementary bodies.

72 hours after initial infection

The infected epithelial cell and the phagosome containing elementary bodies rupture, releasing the elementary bodies into the circulation.

Chlamydia trachomatis

What species of Chlamydia completes its life cycle in 48 hours?

Chlamydia pneumoniae

What species of Chlamydia completes its life cycle in 72 hours?

Febrile pattern for Chlamydia trachomatis

Fever appears and disappears on the 1st day and reappears after 2 days.

Fever pattern for Chlamydia pneumoniae

Fever appears and disappears on the 1st day and reappears after 3 days.

the immune system can no longer recognize the elementary bodies, and the fever subsides

Why does the febrile reaction disappear after the elementary bodies enter the epithelial cell?

Pelvic Inflammatory Disease (PID)

What type of infection is Chlamydia trachomatis a major cause of?

neonatal pneumonia and inclusion conjunctivitis

What other infections can Chlamydia trachomatis cause?

human-to-human by sexual contact

How is Chlamydia trachomatis transmitted?

17 serotypes (A-L)

How many serotypes/serovars does Chlamydia trachomatis have?

L4

Serotype that is least studied and not associated with any infection

serotype-specific antigen,

as well as species-specific and genus-specific antigens

main antigenic composition of Chlamydia trachomatis

helps each serotype cause a specific infection, and is essential for its pathogenicity

What does the serotype-specific antigen do for Chlamydia trachomatis?

• Endemic / Ocular Trachoma

• Lymphogranuloma venereum (LGV)

• Oculogenital infections

• Perinatal infections

4 primary diseases produced by Chlamydia trachomatis

chronic keratoconjunctivitis

What is Endemic/Ocular Trachoma commonly referred to as?

Endemic/Ocular Trachoma

considered a major cause of preventable blindness worldwide

hand-to-eye inoculation from fomites

What are the primary routes of transmission for Chlamydia trachomatis in Endemic/Ocular Trachoma?

A, B, Ba, and C

Which serotypes of Chlamydia trachomatis cause Endemic/Ocular Trachoma?

inflammation of the conjunctiva,

chronic inflammation leading to scarring of the conjunctiva,

misdirected eyelashes —> corneal damage — > eventual blindness

What are the manifestations of Endemic/Ocular Trachoma?

microscopic examination of conjunctival scrapings

What is the definitive diagnosis for Endemic/Ocular Trachoma?

Halberstandter-Prowazek bodies

Name of the inclusion bodies found in microscopic examination of Endemic/ocular trachoma

iodine (mahogany color) or Giemsa (blue)

Halberstandter-Prowazek bodies can be stained with?

Lymphogranuloma Venereum (LGV)

known as "climatic bubo," "tropical bubo," and "esthiomene."

1. Primary stage

2. Secondary stage (acute lymphadenitis)

3. Tertiary stage

three stages of Lymphogranuloma Venereum (LGV)

Primary stage of LGV

involves a small, painless genital lesion or elevation in the genital area. Most patients don’t seek medical attention at this stage due to the lesion's mild and painless nature.

Secondary stage of LGV

marked by acute lymphadenitis (inflammation of the lymph nodes), particularly in the inguinal area, causing pain. This stage prompts patients to seek medical attention, although by this time the infection has already spread.

Tertiary stage of LGV

life-threatening and can manifest as:

• Genital hyperplasia

• Rectal fistulas/strictures

• Draining sinuses

• Appearance of a bubo (swollen lymph node) in the inguinal area.

sexual contact

Route of transmission for Lymphogranuloma Venereum (LGV)

L1, L2, and L3

Which serotypes of Chlamydia trachomatis cause Lymphogranuloma Venereum (LGV)?

Isolation of the serotypes from the lymphadenitis in the inguinal area

Lymphogranuloma venereum Laboratory diagnosis

very low

What is the specificity of the test for isolating serotypes of Chlamydia trachomatis in LGV?

Frei’s test

An intradermal skin test used for diagnosing LGV by injecting the LGV antigen. However, it has low sensitivity and specificity because it only detects genus-specific antigens and can give false-positive results.

Oculogenital Infections

Acute inclusion conjunctivitis; Associated with purulent discharge

Oculogenital infection usually affects adults, whereas ocular trachoma typically affects newborns or children.

How does oculogenital infection differ from ocular trachoma in terms of affected age groups?

• Urethritis

• Cervicitis

• Bartholinitis

• Proctitis

• Salpingitis

• Epididymitis

• Acute urethral syndrome

What other conditions can be caused by oculogenital infections?

• Sexual contact (found in genital area)

• Hand-to-eye transmission (auto-inoculation of genital secretions)

• Eye-to-eye transmission (via infected secretions and purulent discharge)

• Neonatal transmission (from infected mother to baby during birth)

Routes of transmission for oculogenital infections

D-K

Which serotypes of Chlamydia trachomatis cause Oculogenital Infections?

passed from the infected mother to the newborn during delivery or birth.

How are perinatal infections caused by Chlamydia trachomatis transmitted to newborns?

common symptoms of perinatal infections in newborns

Newborns will develop inclusion conjunctivitis, some develop pneumonia also on the part of the newborn

Swabbing of the affected anatomic site (Endocervix)

Perinatal Infection Laboratory diagnosis

2SP & SPG

the transport medium that is commonly used for chlamydia trachomatis isolation

2-Sucrose-Phosphate (2SP)

It is Routinely used and recommended transport medium for swab specimens of chlamydia trachomatis because it has an incorporated antimicrobials in the name of Gentamicin, vancomycin, and nystatin.

Sucrose-Phosphate-Glutamate (SPG)

Good but not routinely used and recommended as it does not contain antimicrobials that will suppress the growth of normal flora collected from the swab specimen.

Potassium dihydrogen phosphate and Disodium hydrogen phosphate

What is P in Sucrose-Phosphate-Glutamate (SPG)

After all other specimens have been collected.

When should culture specimens for Chlamydia trachomatis be obtained in perinatal infections?

McCoy cells, HeLa cells, and monkey kidney cells.

What types of cell lines are used for culturing Chlamydia trachomatis in perinatal infections?

The specimen is centrifuged, then stained with iodine, Giemsa, or immunofluorescent stain to examine for inclusion bodies.

After swabbing and transport, what is the next process in culturing Chlamydia trachomatis?

Because the organism is intracellular and hidden within host epithelial cells, it does not show clear results on standard plate testing methods.

Why is antimicrobial susceptibility testing not useful for Chlamydia trachomatis?

Sulfonamides

Despite the limits of susceptibility testing, what class of antibiotics is Chlamydia trachomatis generally sensitive to?

Cycloheximide-treated with McCoy cells

Best and recommended cell culture for Chlamydia trachomatis.

Ensure that overgrowing of contaminants is prevented and we want only the Chlamydia trachomatis organism to really thrive within the cell present in the cell culture medium.

Cycloheximide

Is an antimicrobial

Chlamydophila

new genus name of Chlamydia

Inhalation of aerosols from contaminated bird feces; no human-to-human transmission.

Mode of transmission of Chlamydophila psittaci to humans?

Psittacine birds such as parrots and parakeets; also turkeys and pigeons.

What types of birds commonly carry Chlamydophila psittaci?

Psittacosis or Ornithosis

What disease does Chlamydophila psittaci cause?

Pneumonia, severe headache, changes in mentation, hepatosplenomegaly, usually after bird contact.

Clinical manifestations of psittacosis

Turkey processing workers and pigeon aficionados

Which groups are most at risk for Chlamydophila psittaci infection?

Levinthal-Cole-Lillie (LCL) bodies

What are the inclusion bodies found in Chlamydophila psittaci infections which are stained using Giemsa or Macchiavello stain?

Biosafety Level 3 (BSL-3)

What biosafety level is required to process Chlamydophila psittaci specimens?

Complement fixation (CF) and Indirect microimmunofluorescence.

What serologic methods are used in diagnosing Chlamydophila psittaci?

sulfonamide-resistant

What is the antibiotic resistance characteristic of Chlamydophila psittaci?

Tetracycline

Drug of choice for Chlamydophila psittaci

TWAR strain – from TW-183 (Taiwan) and AR-39 (United States)

What is another name for Chlamydophila pneumoniae based on its strain origin?

Taiwan Acute Respiratory strain

What does TWAR stand for?

Pneumonia

What infection does Chlamydophila pneumoniae primarily cause?

Mycoplasma pneumoniae infection

What is the main differential diagnosis for Chlamydophila pneumoniae infection?

Pear-shaped

What is the shape of the elementary body of Chlamydophila pneumoniae?

Aerosol droplets

How is Chlamydophila pneumoniae transmitted?