1. Chlamydiae

2. Chlamydiae Chlamydiae are small gram-negative
bacteria which obligate intracellular parasites
and multiply in the cytoplasm of their host
cell by a distinctive developmental cycle.

3. Classification 1. chlamydia trachomatis 2. chlamydia psittaci
on the basis of antigen composition, intracellular inclusion, sulfonamide susceptibility and disease production,they are divided into 4 species:
1.  chlamydia trachomatis
2.  chlamydia psittaci
3.  chlamydia pneumeniae
4.  chlamydia pecorum

4. Classification C. trachomatis can be divided into three biovars:
(1)  Biovar trachoma
Serovars(serotype): A, B, Ba, C,D,Da,E,F,
G,H,I,Ia,J,and K 14 serotype.
A,B,Ba and C---trachoma
D～K---sexnaly transmitted infection
(2)  Biovar lymphogranuloma venereum (LGV)
L1,L2,L2a and L3---LGV
(3)  Biovar mouse

5. Characteristics 1. It differs from virus
(1) They possess both RNA and DNA
(2)  Binary fission
(3) They have a rigid cell wall that resembles a bacterial type cell wall(G-). It does not have typical peptidoglycan layer and lacks
muramic acid.

6. Characteristics (4) Ribosome
(5)  They have a variety of metabolically active
enzymes, eg .they can librate CO2 from
glucose. Some can synthesize folates.
(6) Their growth can inhibited by many
antimicrobial drugs, especially tetracycline and erythromycins.

7. Characteristics 2. development cycle
Two particles were found in infected cell.
(1)  Elementary body (EB):
infectious particles, small (0.3µm in
diameter),with an electron-dense nucleoid.
A high affinity for host epithelial cells.

8. Characteristics

9. Characteristics (2) Initial body(IB):
0.5～1 µm, binary(reticulate body)
fission→small particles (inclusion bodies)→
librated→other cell.
The developmental cycle takes hrs.

11. Characteristics 3. antigens (1) genus specific antigen:
It is shared by all chlamydiae.
Heat-stable lipopolysaccharide with 2-keto-3-deoxyoctonic acid.
CF and immunofluorescence

12. Characteristics (2) species-specific antigen.
Major outer membrane protein(MOMP)
Immunofluorescence
(3)  Immunotype-specific antigen
MOMP
McAb

13. pathogenicity 1. pathogenic substances endotoxin-like substance MOMP
2. clinical finding
(1) trachoma
It is a chronic keratoconjunctivits that begins with acute inflammatory changes in the conjunctiva and cornea and rogresses to scarring and blindness.

14. pathogenicity Immunotypes: A,B,Ba,C
Transmission: eye→eye, eye→hand→eye.
C.trachomatis→eye→3～10 day→earliest symptoms: lacrimation, mucopurulent discharge, conjunctival hyperemia, follicular hypertrophy→conjunctiva scar→trichiasis→ eyelashe sweeping corna→blindness.

15. pathogenicity (2) Genital chlamydial infections Immunotypes: D-K
Transmission: sexual contact
It is a promiment cause of nongonococcal urethritis, epididymitis (in male),urethritis,
cervicitis,salpingitis and pelvic inflammatory
(in female), Up to 50% of nongonococcal or
postgonococcal urethritis or the urethral
syndrome is attributed to chlamydiae and
produces dysuria,nonpurulent discharge.

16. pathogenicity Inclusion conjunctivitis:
Immunotype: B,Ba,D,Da,E,F,G,H,I,Ia,J and K
Newborn---infected birth canal
Adults---sexual contact
Inclusion conjunctivitis in adults results from
self-inoculation of genital secretion.

17. pathogenicity (3) Lymphogranulom venereum(LGV)
LGV is a sexually transmitted disease
characterized by suppurative inguinal adenitis.
L1-L3

18. pathogenicity (4) psittacosis
psittacosis is a disease of birds that may be
transferred to humans. In human,the agent,
C. psittaci, produces a spectrum of clinical
manifestations ranging from severe pneumonia and sepsis with a high mortality rate to a mild inapparent infection.

19. pathogenicity (5) C. Pneumoniae (TWAR) TW-138 AR-39 Human to human
Respiratory infection→pnenmoniae
TWAR

20. Laboratory liagnosis 1. cytolcgy 2. cuture 3. serology ELISA
4. Nucleic acid probes: PCR, ligase chain
reaction(LCR)