Download Chlamydia trachomatis

Chlamydiaceae
2 genera
1.
Chlamydia
1.
2.
Chlamydia trachomatis
Chlamydophila
1.
2.
Chlamydophila psittaci
Chlamydophila pneumoniae
Chlamydiaceae

Small enough to pass through 0.45 mm filters

Obligate intacellular parasites
Are they viruses?
They are bacteria.... :
Possess inner and outer membranes
(as Gram- negative bacteria) Cell wall +
 DNA & RNA
 Prokaryotic ribosomes
 Synthesize their own proteins, nucleic acids,
lipids
 Susceptible to numerous antibacterial
antibiotics
 Cell wall but no peptidoglycan!!

Chlamydiaceae/ Physiology & structure

Exist in
morphologically distinct forms
1.
Elementary body

infectious
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Resistant to harsh environmental conditions
No replication in this form
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Reticulate body
2.
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Noninfectious
Metabolically active
fragile
Downloaded from: StudentConsult (on 22 May 2011 04:15 PM)
© 2005 Elsevier

Cell wall

The major outer membrane protein
(MOMP)

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Different for each species.
Variable regions in the gene encoding this
protein are found in C. trachomatis and are
responsible for serologic variants (called
serovars-serotypes).
Chlamydia trachomatis
biovars exist

1.
2.
Trachoma
LGV (lymphogranuloma venereum)
These have been further divided into 19
serotypes
 Trachoma: A, B, Ba, C, D, Da, E, F, G, Ga,
H, I, Ia, J, K
 LGV:
L1, L2, L2a, an L3
Chlamydia trachomatis/ Diseases
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Trachoma
Adult inclusion conjunctivitis
Neonatal conjunctivitis
Infant pneumonia
Ocular lymphogranuloma venereum
Urogenital infections

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Urethritis, cervicitis, endometritis, salpingitis,....
Lymphogranuloma venereum
Epidemiology
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Most common sexually transmitted bacteria
in United States
Ocular trachoma primarily in North and subSahara Africa, the Middle East, southern
Asia, South America
LGV highly prevalent in Africa, Asia, and
South America
Chlamydia trachomatis/pathogenesis & immunity

Infects nonciliated, cuboidal or transitional
epithelial cells
in
Mucous membranes of the urethra, endocervix,
endometrium, fallopian tubes, anorectum,
respiratory tract, conjunctivae
Chlamydia trachomatis/epidemiology
Pulmonary infection
 in newborns
 a diffuse interstitial pneumonia in
20 %
10-
Chlamydia trachomatis/epidemiology

“C. trachomatis is thought to be the most
common sexually transmitted disease in
US”
4 million new cases /year,
50 million new cases/year, worldwide
 most with serotypes D-K
with N. gonorrhoeae, most common cause
of epididymitis in sex. act. men
 15% of the cases of proctitis in ½ men
Chlamydia trachomatis/epidemiology
LGV
 is a chronic STD
 C. trachomatis serotypes L1, L2, L2a, L3
 sporadic in N. America, Australia, Europe
 highly prevalent in Africa, Asia, S. America
 in US, male homos. being the major
reservoir
Chlamydia trachomatis/Clinical Diseases
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Trachoma
serovars A, B, Ba, C
follicular conjunctivitis
scarred
conjunctiva
eyelids turn inward
in-turned eyelashes abrade cornea
corneal ulceration, scarring, pannus
formation
LOSS OF VISION
Chlamydia trachomatis/Clinical Diseases
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Urogenital infections I
most GTI in women are asymptomatic 80 %
may become symptomatic
clinical manifestations:
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cervicitis, endometritis, urethritis, salpingitis,
bartholinitis, perihepatitis
A mucopurulant discharge and hypertrophic
ectopy are seen in symptomatic patients
Chlamydia trachomatis/Clinical Diseases
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Urogenital infections II
most genital infections in men are
symptomatic ( 75%)
35-50 % NGU are caused by Ct
dual infections with N. gonorrhoeae not
uncommon
Chlamydia trachomatis/Clinical Diseases
Urogenital infections III
Reiter’s syndrome
 urethritis, conjunctivitis, polyarthritis, and
mucocutaneous lesions
 caused by Chlamydia trachomatis !! ??
Chlamydia trachomatis/Clinical Diseases
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Lymphogranuloma venereum
1-4 weeks of incubation
primary lesion
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penis, urethra, glans, scrotum, vaginal wall, cervix,
vulva
often overlooked: small, “painless”, heals rapidly
secondary stage
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inflammation and swelling of the lymph nodes
inguinal nodes, most commonly involved
buboes
Chlamydia trachomatis/Laboratory diagnosis
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symptomatic infections are easier to
diagnose than asymp.infc.
the quality of the specimen is important
intracellular bacteria
a specimen of pus or urethral exudate is
inadequate
( 30 % of specimens submitted for study in patients with
suspected Chlamydia infection are inappropriate)
Diagnosis

Molecular amplification tests are the most
sensitive and specific tests currently available
Chlamydia trachomatis/Laboratory diagnosis
Serology

detection of specific IgM antibodies in infants
with chlamydial pneumonitis
Chlamydia trachomatis/Laboratory diagnosis
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Serology
can be helpful in the diagnosis of LGV
Chlamydia trachomatis/Prevention & Control
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Prevention
difficult population with
endemic disease (limited access to medical care)
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Chlamydia conjunctivitis and genital
infections
safe sexual practices
Chlamydophila pneumoniae

First isolation
from the conjunctiva of a
child in Taiwan
TW-183 (related to AR39)
TWAR
Chlamydia pneumoniae
Chlamydophila
Chlamydophila pneumoniae/Epidemiology
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It’s a human pathogen
important cause of bronchitis, pneumonia,
and sinusitis
transmission: person-to-person by respiratory
secretions
common: 200 000-300 000 cases annually
>50 % of people have serologic evidence of
past infections
Chlamydophila pneumoniae/Clinical Diseases
most infections are asymptomatic or
mild
 persistent cough and malaise
 cannot be differentiated from other
atypical pneumonias
 Is there a role of C. pneumoniae in
the pathogenesis of atherosclerosis ?

Chlamydophila pneumoniae/Laboratory diagnosis
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NA techniques
serology!!
Chlamydophila psittaci
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The cause of psittacosis
“parrot fever” (psittakos is “parrot” in Greek)
The natural reservoir is any species of bird

Ornithosis, ornithos= bird
Chlamydophila psittaci/epidemiology
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Infection in:
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Humans, sheep, cows, goats
In: blood, tissues, feces and feathers of
infected birds
Infection occurs by means of the respiratory
tract (RES of the liver & spleen
blood)
Chlamydophila psittaci/epidemiology
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Transmission:
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Inhalation of dried bird excrement,
urine or respiratory secretions
“Most infections result from exposure
to psittacine birds” (parrots (a tropical bird with a
curved beak, which is often kept as a pet and can be trained to copy the human
, parakeetsa small parrot with a long tail, macaws(a
brightly coloured bird of the parrot family found in Central and South America),
cockatiels)
voice)
Chlamydophila psittaci/epidemiology
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Person-to-person transmission
is rare
 Veterinarians,
“are @
 Zookeepers
increased
 Pet shop workers
risk”
 Employee of poultryprocessing plants
Chlamydophila psittaci/clinical disease
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Incubation:
5-14 days
Pulmonary signs
CNS involvement is common (death may
occur)
GIT symptoms
...
Chlamydophila psittaci/Laboratory diagnosis
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Based on serologic findings: antibody
detection
Species specific MIF test
Chlamydophila psittaci/Prevention and control
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Psittacosis can only be prevented through
the control of infections in domestic and
imported pet birds
No vaccine!