2. Small Gram-negative bacteria (Stain poorly
with Gram’s stain)
Like Bacteria
Have both DNA and RNA, Ribosomes, a Cell
wall, and Divide by Binary fission
Like Viruses
Obligate intracellular parasites
Differ from Bacteria
Have no peptidoglycan in their cell wall
Can not produce their own ATP
Require to use host ATP (Energy parasite)
3. Chlamydia species
C. trachomatis
3 biovars
Those causing trachoma and inclusion
conjunctivitis (TRIC)
Those causing lymphogranuloma
venereum (LGV)
The one causing mouse pneumonitis (MoPn)
C. psittaci > Infect both mammals and birds
C. pneumoniae > both humans and animals
C. pecorum > Some infect mammals
5. Can be stained with Giemsa stain
Elementary body (EB)
Extracellular, infectious metabolically
inert form of chlamydiae
Reticulate body (RB)
Intracellular, non-infectious,
metabolically active particle
6.
7. Infection to Humans
Ocular infection
Trachoma > in countries where sanitation
and hygiene standards are poor
Spread by eye seeking flies, or fingers,
from one patient to another
Blindness
“Trachoma belt” > North Africa to South-East
Asia
Adult inclusion conjunctivitis
(paratrachoma)
Acute stage >> follicular conjunctivitis
Self-limited
8. Chlamydial ophthalmia neonatrum
(inclusion blennorrhoea)
5-21 days after birth
If not treated > after 1 year >
secondary bacterial infection >
ocular damage and even blindness
Source:
infected genital tract of the mother
9. Genital infection
C. trachomatis is the Commonest
cause of non-gonococcal urethritis
in males (30%)
LGV
In both males and females in
tropics and subtropics
10. In females
Mucopurulent cervicitis and
urethritis
Vaginitis and vaginal discharge
Asymptomatic females if not
treated
Ascending infection >> Pelvic
inflammatory disease (endometritis
or salpingitis or both)
Tubal damage >> ectopic pregnancy
and infertility
11. Infection in pregnancy
C. psittaci
Miscarriage or intra-uterine death
Patients had contact with sheep
C. trachomatis
Isolated from abortion products
12. Respiratory infection
C. pneumoniae
3rd
or 4th
cause of pneumonia
Pharyngitis, bronchitis, otitis and
sinusitis
C. psittaci
Psittacosis in humans from avian
strains
Disease ranges from an influenza-like
illness, to severe illness with typhoidal
state ad pneumonia.
13. C. trachomatis
Pneumonitis in neonates
(infection acquired from the
mother)
14. Laboratory Diagnosis
Cultivation
MacCoy cells treated with
cycloheximide
Organism detected by staining for
inclusions or EBs
Detects only living cells
Antigen detection
Using probes for DNA or mRNA that
identify the infected cells
PCR
Amplification of parts of the genome
16. Serology
Micro-immunofluorescence test
Using Ags from all chlamydial
strains to detect species-specific
and serovar-specific Ab
Complement fixation test
Detecting Ab in serum directed
against group Ag
18. Treatment and Control
Chemotherapy
Tetracycline in adults and Erythromycin
in babies
For 3 weeks
Azithromycin
Single dose
Contact tracing
Partners of index cases (even if
clinically normal)
Neonatal infection
Both parents should be treated
19. Animal contact
Avoidance of contact with sources of
infection (specially pregnant women)
Sheep, milking and shearing
Control of importation of psittacine
birds
Hygiene