Chlamydia trachomatis, respiratory tract diseases caused by Chlamydia Flashcards
General Features and habitat of Chlamydiae Species (Chlamydia trachomatis)
Gram – (stains poorly with Gram staining) Pleomorphic shape (ovoid)
Reservoir- human genital tract and eyes
Biochemical Properties of Chlamydiae Species
Obligate intracellular- cannot create his own ATP
Cell wall lacks muramic acid (no peptidoglycan)- but contains LPS
Bi-Phasic Life Cycle: Elementary bodies (EB)- extracellular, infecting (inactive) form Reticular bodies (RB)- intracellular, replicating (active) form
Elementary stage: bacteria outside of cells (infecting)
Reticular stage: The bacterium enters cell and replicate by binary fission into 2 bacteria,
then is released as elementary bodies and the cycle begins all over
Pathogenesis of Chlamydiae Species
Transmitted by sexual contact (STD), at birth or by contaminated hands touching eyes
Clinical Features of Chlamydiae Species
Trachoma (inclusion conjunctivitis)
Chlamydia (Sexually Transmitted Infection- STI) serotypes D-K
Lymphogranuloma Venereum (LGV)- serotypes L1-L3 (also STI but less common)
Complication- Sexually Acquired Reactive Arthritis (SARA)
Autoimmunity (cross-reactivity) causing a triad of symptoms (A.K.A Reiter’s syndrome)
Trachoma (inclusion conjunctivitis)- serotypes A-C (A, B, Ba, C)
Blindness (leading cause of blindness in the world)
Due to chronic conjunctivitis that leads to conjunctival scarring and corneal scarring
Chlamydia (Sexually Transmitted Infection- STI)- serotypes D-K
Watery discharge (in contrast with N. gonorrhea which has purulent discharge)
Lead to Pelvic Inflammatory Disease (PID), if left untreated- can cause infertility
In females: NGU, vaginitis or cervicitis; in males: urethritis, prostatitis
In newborns to infected mother- conjunctivitis and pneumonia (staccato cough)
Conjunctivitis occurs after ~1 week (compared to N. gonorrhea after 2-4 days)
Lymphogranuloma Venereum (LGV)- serotypes L1-L3 (also STI but less common)
Present first with painless ulcers at the site of contact
Progress to swollen, tender lymph nodes (lymphadenopathy) at inguinal region
Tertiary (late) stage presents with ulcers, fistulas and genital elephantiasis
Sexually Acquired Reactive Arthritis (SARA)
Autoimmunity (cross-reactivity) causing a triad of symptoms (A.K.A Reiter’s syndrome)
Reactive arthritis- usually in knees (joint inflammation)
Uveitis (eye inflammation)
Urethritis (urethra inflammation)
Diagnosis of Chlamydiae Species
Giemsa staining or IF- inclusion bodies in cytoplasm of infected cells seen in microscope
ELISA- antigen detection from urine / other exudate or antibody detection
NAAT (Nucleic-Acid Amplification Test) = PCR
Treatment of Chlamydiae Species
Macrolides (e.g. Azithromycin) or Doxycycline (Tetracycline)
Ceftriaxone- use if co-infected with N. gonorrhea, can treat both empirically
Distinguishing Characteristics of Chlamydophila pneumoniae (TWAR* agent)
Potential association with atherosclerosis (plaque formation)
Reservoir of Chlamydophila pneumoniae (TWAR* agent)
Human respiratory tract
Transmission of Chlamydophila pneumoniae (TWAR* agent)
Respiratory droplets (common among school-aged children)
Pathogenesis of Chlamydophila pneumoniae (TWAR* agent)
Intracellular growth- incubation period takes several weeks
Smooth muscle
Endothelial cells (of coronary arteries)
Macrophages
Obligate human pathogen
Clinical Features of Chlamydophila pneumoniae (TWAR* agent)
Atypical (“walking”) pneumonia- affect single lobe
Minimal sputum
Prominent dry cough
Hoarseness
Can lead to bronchitis, sinusitis or pharyngitis
Diagnosis of Chlamydophila pneumoniae (TWAR* agent)
Culture on living susceptible cell lines
Serology (most important)- from serum Complement fixation (CF) Indirect immunofluorescence (MIF) or ELISA
PCR- detects as few as 10-100 EBs from specimens include:
nasopharyngeal or throat swabs, broncho-alveolar lavage
Treatment of Chlamydophila pneumoniae (TWAR* agent)
Macrolides (Erythromycin) or Doxycycline (Tetracycline)
Prevention of Chlamydophila pneumoniae (TWAR* agent)
None
Distinguishing Characteristics of Chlamydia psittaci
No glycogen in inclusion bodies
Reservoir of Chlamydia psittaci
Zoonosis- birds, parrots, turkeys (domestic and wild)
Transmission of Chlamydia psittaci
Dust from dried birds’ secretions and feces
Pathogenesis of Chlamydia psittaci
Intracellular growth
Clinical Features of Chlamydia psittaci
Psittacosis (A.K.A Ornithosis or Parrot Fever)
Atypical pneumonia with hepatitis
Cough may be absent
If present- unproductive first, then scant mucus
CNS and GI symptoms may be present
May also cause meningoencephalitis, myocarditis
Diagnosis of Chlamydia psittaci
Culture on living susceptible cell lines
Serology (most important)- from serum Complement fixation (CF)- 4x increase in antibody titer Indirect immunofluorescence (MIF) or ELISA
PCR- detects as few as 10-100 EBs from specimens include:
nasopharyngeal or throat swabs, broncho-alveolar lavage
Treatment of Chlamydia psittaci
Macrolides (Erythromycin) or Doxycycline (Tetracycline)
Prevention of Chlamydia psittaci
Chemoprophylaxis of exotic birds with Tetracycline
