1. Chlamydia
Filename: Chlamydia.ppt

2. Chlamydia

3. Chlamydia Obligate intracellular coccoid parasites
contain DNA and RNA, and ribosomes
lack ATP, biosynthetic pathways
cell wall but peptidoglycan absent -
use disulfide bonds
non motile

4. Obligate Parasites
Obligate intracellular parasites of mammals and birds
not transmitted by arthropods.
incorrectly called the PLT viruses or Bedsonia or basophilic viruses,
Multiply in the cytoplasm of the host cell.
generally epithelial cells
Basophilic inclusions

5. Similar to Viral Infections
The methods used to study Chlamydia are those of the virologist rather than the bacteriologist.
The clinical features, pathogenesis, pathology and epidemiology of chlamydial infections are similar to those of viral infections.

6. Energy Parasites The cells can synthesize DNA, RNA and protein.
No flavoproteins or cytochromes.
lack of ATP-generating ability
need to obtain ATP from the host cell.

7. Three species:
C. trachomatis
C. psittaci
C. pneumoniae

8. Ecology Chlamydia form two main ecological groups. Infect only humans
Subgroup A
trachoma, inclusion conjunctivitis, and lymphogranuloma venereum
Zoonotic Infections
Subgroup B
Respiratory tract infections

9. Zoonotic Infections transmitted to man
About 100 species of birds are naturally infected with chlamydia.
71 species of parrots
finches, pigeons, chickens, ducks, turkeys and seabirds.

10. C trachomatis C psittaci & C pneumoniae Trachoma conjunctivitis
proctitis
urethritis
salpingitis
Lymphogranuloma venereum
C psittaci & C pneumoniae
Upper respiratory infection
Bronchitis
Pneumonia

11. Chlamydial Morphologies
Elementary body
um diameter
electron-dense nucleoid
Released from ruptured infected cells. Human to human
& bird to human.
Reticulate Body
Intracytoplasmic form um
Replication and growth. ( Inclusion body )
without a dense center.

12. Developmental Cycle of Chlamydia
There appears to be no significant difference in morphology or developmental cycle among the various chlamydia, and a single generalized description applies to all. The development cycle may be regarded as an orderly alternation of the small and large cell type. It is initiated by the highly infectious small cell which is taken into the host cell by phagocytosis. The engulfed small cell
retains its morphological integrity in vacuoles bound by membrane derived from the surface of the
host cell, and there is no eclipse (period in which the parasite loses the infectious ability). Instead,
without loss of individuality, the small cell is reorganized into a large cell which is the vegetative
multiplying form of these organisms. Then, still within the membrane-bound vacuole, the large
cell grows in size and multiplies by repeated binary fission. The developmental cycle is completed
by the reorganization of most of the large cells into small ones which are then available for
infection of new host cells. The time required for completion of a cycle varies from hours,
depending on the particular host/parasite system involved.

13. C trachomatis elementary bodies

14. C trachomatis inclusions
Glycogen Inclusions

15. Subgroups Subgroup A Mammalian parasites Compact inclusions
Glycogen synthesized
Folates synthesized
Sensitive to D-cycloserine
Restricted host range
Chlamydia trachomatis
Subgroup B
Primarily bird parasites
Diffuse inclusions
Glycogen not synthesized
Folates not synthesized
Resistant to D-cycloserine
Broadening of host range
Chlamydia psittaci

16. Evolution of Chlamydia
Gram-negative cocci
Facultative intracellular parasites of mammals
Obligate intracellular parasites
Host range restricted to rodents
Restricted virulence (compact inclusions)
Folates synthesized (sulfonamide susceptible)
Glycogen synthesized and deposited in inclusions

17. Conjunctivitis Inclusion conjunctivitis: Infantile conjunctivitis:
Transmitted by infectious secretions of the genitourinary tract
autoinoculation
Infantile conjunctivitis:
Acquired in the birth canal days after birth
most common type of conjunctivitis
Antibiotic prophylaxis: erythromycin, tetracycline.

18. Chlamydial Infection of Ocular Conjunctiva

19. Trachoma infection of conjunctival epithelial cells.
subepithelial infiltration of lymphocytes.
Infected epithelial cells contain cytoplasmic inclusion bodies
Cell infiltrations to cornea cause clouding
Trichiasis: abnormal inward growth of eyelashes.

20. Predisposing factors:
climate - hot , dry
shortage of water
standards of hygiene low
Transmitted by flies, dirty towels, fingers, cosmetic eye pencils.
Initial infection in childhood mostly by years of age.

21. Trachoma
Almost six million people have become blind and another 540 million almost 10% of the world’s population are at risk

22. Trachoma Incidence

23. Chlamydia trachomatis Clinical disease
lymphogranuloma venereum
nongonoccal urethritis (NGU)
epididymitis
salpingitis
mucopurulent cervicitis
pelvic inflammatory disease (PID)
Reiter's syndrome
neonatal chlamydia
Reiter syndrome urethrritis conjunctivitis, polyarthritis and mucocutaneous lesions

24. Chlamydia: Rates by Gender

25. Chlamydia Symptoms In Men
Symptoms usually appear between 7 and 28 days after infection, usually with mild burning when urinating, a more frequent need to urinate, and a white discharge from the penis. Occasionally, blood may appear in the urine. The symptoms occur most frequently in the morning.

26. Erythematous meatus and urethra with balanitis
Hyperlink to original

27. Chlamydial Urethritis in Males

28. Nongonococcal urethritis (NGU) - Reiter's syndrome
Swollen, painful right knee in which needle aspiration for synovial fluid was performed (yellow discoloration from the betadine prep)
Hyperlink to original site

29. Lymphogranuloma venereum LGV
200 reported cases per year.
Incubation period is 5 to 20 days.
Lesion: Transient vesicles on penis or vagina that are often unnoticed and patients do not usually seek medical advice.

30. Bilateral inguinal adenopathy with overlying erythema
R Roberts MD

31. LGY: "Groove sign"
Pompart's ligament is preserved despite the involvement of multiple inguinal nodes
R Roberts MD

32. LGV: Microscopy
lymph node shows both necrosis and granulomatous reaction (dimorphic necrotizing granulomatous reaction)
R Roberts MD

33. Chlamydia pneumoniae
This bacterium was first recognized in 1983 as a respiratory pathogen, after isolation from a college student with pharyngitis.
Pneumonia or bronchitis, gradual onset of cough with little or no fever. Less common presentations are pharyngitis, laryngitis, and sinusitis.

34. Incidence
Each year an estimated 50,000 adults are hospitalized with pneumonia in the United States. The overall incidence is unknown.

36. Transmission Person-to-person transmission by respiratory secretions.
Risk Groups
All ages at risk but most common in school-age children. By age 20 years, 50% of population have evidence of past infection. Reinfection throughout life appears to be common.

37. C. pneumoniae Associations
Associated with Heart Disease
infection may be associated with
atherosclerotic vascular disease
Proposed Associations
Alzheimer's diseases, asthma, and reactive arthritis

38. Treatment Chlamydia Children < 45 kg, urogenital & rectal:
erythromycin 50 mg/kg/day in 4 doses for days
Neonates (ophthalmia, infants born to infected mothers):
erthromycin 50 mg/kg/day in 4 doses for days
Adults Conjunctival, urethral, cervical, rectal:
Azithromycin 1 gm x 1 dose
Doxycycline 100 mg BID for 7 days
Ofloxacin 300 mg po BID for 7 days
Erythromycin 500 mg QID for 7 days
Amoxacillin 500 mg TID 7-10 days

39. Chlamydia Antigens Antigens: group specific & species specific
Major outer membrane protein (cysteine-rich)
Eucaryotic cell binding protein
Host response: damage to specific tissues

40. Laboratory Diagnosis Isolate the organism from infected tissue.
Inoculate the yolk sac of seven-day chick embryos
Inoculate McCoy human cells.
Characteristic cytoplasmic inclusion bodies in infected cells.

41. Immunofluorecent tests
Microimmunofluorescent tests
patients with eye infections
Check tears for the presence of anti-chlamydia antibody.
Direct immunofluorescence
of conjunctive cells with fluorescein - conjugated monoclonal antibody is sensitive and specific.
In neonatal conjunctivitis and early trachoma

42. Serological diagnosis:
Immunofluorecent tests
Delayed Type Skin Reaction
Antibodies to Family antigen

43. FREI Test
Delayed-type skin reaction to killed organisms in genitourinary infections

44. Antibodies to Family antigen
Rising titer of antibody against the chlamydial family antigen in lung infections.
Complement fixation test
Fluorescent antibody test.

45. DONE!!!