1. ‫بسم ا الرحمن الرحيم‬
GENUS: CHLAMYDIA
Prof. Khalifa SifawGhenghesh

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

4.  Trachoma biovars
 14

Serovars: A-K
Serovars A, Ba, B, C
 Classic trachoma

Serovars D-K
 Inclusion conjunctivitis and Genital
infections
 LGV biovars
3
Serovars: L1, L2, L3

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

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

15. Chlamydia trachomatis
from a urethral scrape

16.  Serology
 Micro-immunofluorescence

Using Ags from all chlamydial
strains to detect species-specific
and serovar-specific Ab
 Complement

test
fixation test
Detecting Ab in serum directed
against group Ag

17. Chlamydia psittaci
Direct FA stained mouse brain impression smear

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