1. Chlamydia trachomatis
The Biology of a Sexually Transmitted Bacterium

3. Chlamydial Life Cycle
Reticulate body, obligately intracellular in eukaryotic cells
Elementary body, metabolically inert, an extracellular spore-like state
48-72 hour cycle

8. Chlamydial Biology Prokaryotes Gram negative with LPS
Lack peptidoglycans?
Obligate intracellular life cycle

9. Chlamydial Genome 1.043 million base pairs
Missing genes for amino acid and purine-pyrimidine biosynthesis, anaerobic fermentation, and transformation competence proteins
Contains genes for LPS, glycolysis, fatty acid and phospholipid synthesis, peptidoglycan synthesis

10. Chlamydia trachomatis: Disease Presentations
Perinatal infections
Genitourinary tract infections
Trachoma

11. Chlamydia trachomatis and Sexually Transmitted Infections
Urogenital infections: cervicitis, urethritis, PID, epididymitis/prostatitis
4-6 million cases/year, U.S.
Prevalence highest in young women, 3-11% (age 15-24)
Lymphogranuloma venereum

15. Serious Consequences of C. trachomatis STI's
Tubal infertility
Ectopic pregnancy
Reactive arthritis (Reiter's syndrome)

18. C. trachomatis Perinatal Infections
Neonatal inclusion conjunctivitis (20-45% of infants from infected mothers)
Infant pneumonia (10-20% of infants from infected mothers)

19. C. trachomatis and Trachoma
Blinding conjunctival infection
600 million cases worldwide
Develops over years, chronic inflammation
Endemic in Middle East, Asia

23. C. trachomatis: Diagnosis
Serology (MIF=microimmunofluorescence)
Culture
EIAs/DFA (direct fluorescent antibody)
Direct hybridization
Nucleic acid amplification (PCR, LCR, others)

26. C. trachomatis: NA Amplification
Nucleic acid amplification can be used on urine, cervical/urethral specimens
Vaginal specimens also have been used
Sensitivity, 90%+, specificity >99%
Identifying more male cases, providing easier specimen collections

29. C. trachomatis: Treatment
Azithromycin,
(single 1000 mg dose acceptable)
Tetracyclines (erythromycin in children)

30. Chlamydia pneumoniae 1983, described as a distinct chlamydial pathogen
Less than 10% DNA homology with C. trachomatis
Similar life cycle but different cell wall construction

31. C. pneumoniae: Disease Presentations
Pharyngitis, bronchitis
Pneumonia (7-10% of cases)
Other syndromes (otitis media, endocarditis)

32. C. pneumoniae and Chronic Diseases
Atherosclerosis (seroepidemiologic studies, experimental disease)
Asthma
Neurological disease? (MS, Alzheimer’s)

33. C. pneumoniae: Diagnosis
Serology (MIF = microimmunofluorescence)
Culture
PCR

34. C. pneumoniae: Treatment
Azithromycin/clarithromycin (macrolides)
Erythromycin
Tetracycline/doxycycline

35. Chlamydophila psittaci
Recently distinguished as a separate genus using sequence phylogeny
Zoonosis, typically from pet birds, occupational exposure
80 cases/year in the U.S

36. Chlamydophila psittaci: Clinical Disease/Dx/Tx
Severe pneumonia
Endocarditis, other systemic presentations
Diagnosis by serology, culture
Prolonged therapy with tetracycline