Transcript Chlamydia and Chlamydophila species1.14 MB

Chlamydiaceae
•two genera, Chlamydia and Chlamydophila
•small enough to pass through 0.45-μm
filters
•obligate intracellular parasites
•possess inner and outer membranes similar
to those of gram-negative bacteria
•contain both DNA and RNA
•possess prokaryotic ribosomes
•synthesize their own proteins, nucleic
acids, and lipids
•susceptible to antibiotics.
Chlamydiaceae
• metabolically inactive infectious
forms (elementary bodies [EBs])
• metabolically active, noninfectious
forms (reticulate bodies [RBs])
• EBs are resistant to many harsh
environmental factors
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Characteristic
Size
Elementary body
0.2-0.3 μm
Reticulate body
1 μm
Morphology
Electron-dense
core, rigid
Infectious
Fragile,
pleomorphic
Non-infectious
Metabolic activity
1:1 (condensed
DNA core)
Relatively inactive
Trypsin digestion
Resistant
3:1 (increased
ribosomes)
Active, replicating
stage
Sensitive
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Infectivity to host
RNA: DNA ratio
Chlamydiaceae
•The growth cycle of Chlamydia trachomatis
• Electron micrograph of a
thin section of chlamydial
inclusion showing small
elementary body (single
arrow) and reticulate body
(double arrows)
Chlamydia trachomatis
• three biovars, trachoma, LGV
(lymphogranuloma venereum), and mouse
pneumonitis
• serovars-major outer membrane protein
• A, B, Ba, C Primarily conjunctiva
• D-K
Primarily urogenital tract
• L1, L2, L2a, L3
Inguinal lymph nodes
Chlamydia trachomatis
• Most common sexually transmitted
bacteria in United States
• Ocular trachoma worldwide (most
common in Middle East, North Africa,
India
• LGV highly prevalent in Africa, Asia,
and South America
Site of infection
Disease
Organism (serovars)
Eye
Trachoma
C. trachomatis (A,
B, Ba, C)
Inclusion conjunctivitis
C. trachomatis (D-K)
Ophthalmia neonatorum
C. trachomatis (D-K)
Contact lens-associated
Parachlamydia spp.
Male
Non-specific urethritis, proctitis, epididymitis
C. trachomatis (D-K)
Female
Cervicitis, urethritis, endometritis, salpingitis, PID, perihepatitis, peri-appendicitis,
infertility with tubal occlusion
C. trachomatis (D-K)
Abortion, premature birth
C. trachomatis (DK)a
Sheep-related abortion
Ch. abortus
Lymphogranuloma venereum
C. trachomatis (L1L3)
Neonatal atypical pneumonia
C. trachomatis (D-K)
Pharyngitis, bronchitis, pneumonia
Ch. pneumoniae
Genital tract
Male and female
Respiratory tract
Simkania
negevensisa
Chronic diseases
Pneumonia
Ch. abortus
Psittacosis, ornithosis
Ch. psittaci
Atherosclerosis, coronary disease
Ch. pneumoniaea
Stroke, multiple sclerosis, sarcoidosis, Alzheimer's disease
Ch. pneumoniaeb
Trachoma: Chronic, inflammatory granulomatous process of eye surface,
leading to corneal ulceration, scarring, pannus formation, and blindness.
Active trachoma, characterized by the presence of lymphoid follicles on the
conjunctiva and intermittent shedding of chlamydiae, is primarily a disease
of children. By contrast, blindness occurs mainly in adults
Adult inclusion conjunctivitis: Acute process with mucopurulent discharge,
dermatitis, corneal infiltrates, and corneal vascularization in chronic
disease. Most prevalent in sexually active young people, being spreadfrom
genitalia to the eye.
Neonatal conjunctivitis
• Acute process characterized by a mucopurulent discharge.
• Develops in infants around 14 days after birth.
• The disease presents as a swelling of the eyelids and orbit,
hyperaemia and a purulent infiltration of the conjunctiva.
• Acquired from the mother during birth.
• If untreated the infection usually resolves, but a substantial
proportion of these infants develop chlamydial pneumonia
about 6 weeks after birth
Genital infection Infection in men
• C. trachomatis serovars D-K are responsible for about 30%
of cases of non-specific urethritis in men.
• This is one of the commonest sexually transmitted
infections worldwide and repeat infections are common.
• The infection is often asymptomatic, with infected men
serving as a reservoir of infection.
• In symptomatic patients, varying amounts of mucopurulent
discharge are produced. Occasionally this progresses to
epididymitis or prostatitis, especially in those aged less
than 35 years.
• It is likely that chronic chlamydial epididymitis may
eventually lead to occlusion of the tube and infertility due
to azoospermia.
Genital infection Infection in
women
• In symptomatic women, C. trachomatis serovars D-K cause
mucopurulent cervicitis and urethritis.
• However, many women harbour the organism asymptomatically in
their cervix.
• Not only a risk to their sexual partners or offspring, but also to
themselves, as ascending infection frequently occurs.
• This results first in an endometritis, in which chlamydiae survive
monthly menstrual shedding of the uterine lining, followed by
infection of the fallopian tubes to cause acute salpingitis.
• Collectively, endometritis and salpingitis are known as pelvic
inflammatory disease, which, in most developed countries, is
largely caused by C. trachomatis.
• Chlamydial pelvic infection may lead to further abdominal
involvement and the formation of pelvic adhesions. Perihepatitis
(Fitz-Hugh-Curtis syndrome) and even peri-appendicitis may
result.
Lymphogranuloma venereum
• Genital tract infection with C. trachomatis
serovars L1-L3 may present as
lymphogranuloma venereum.
• Commonest in the tropics, this condition is
occasionally seen in developed countries.
• It usually begins with a genital ulcer
followed by lymphadenopathy of the
regional lymph nodes.
• Buboes are seen if infection persist, can
spread to the gastrointestinal and genitourinary tracts, causing strictures and, in
rare cases, peno-scrotal elephantiasis.
Chlamydiaceae
• Lymphogranuloma Venereum
• 1 to 4 weeks
• a primary lesion
• inflammation and swelling of the
lymph nodes
• buboes
Chlamydiaceae
•Patient with lymphogranuloma venereum causing
unilateral vulvar lymphedema and inguinal buboes
Chlamydiaceae
• Reiter’s syndrome (urethritis, conjunctivitis,
polyarthritis and mucocutaneus lesions)
LABORATORY DIAGNOSIS
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Cytology
Culture
Nucleic Acid Probes
PCR, LCR
Serology (MIF)
TREATMENT, PREVENTION, AND CONTROL
• LGV tetracycline for 21 days
• Ocular and genital infections in
adults should be treated with one
dose of azithromycin or doxycycline
for 7 days
• Newborn conjunctivitis and
pneumonia should be treated with
erythromycin for 10 to 14 days
Chlamydiaceae
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Chlamydophila pneumoniae
Respiratory secretions
No animal reservoir
Human pathogen
Bronchitis, pneumonia, and sinusitis
50% of people have serologic evidence
A significant cause of acute exacerbations of
asthma
• Atypical pneumonias
• Alzheimer's disease, multiple sclerosis, stroke
and sarcoidosis, but the evidence is even more
slender than for heart disease
Chlamydophila pneumoniae
• MIF
• NAAT
• Macrolides (erythromycin ,
azithromycin , clarithromycin ),
tetracyclines (tetracycline,
doxycycline ), or levofloxacin
administered for 10 to 14 days
Chlamydophila psittaci
• the cause of psittacosis-parrot fever
• human infections may be asymptomatic or
mild
• exposure to an infected bird may not be
suspected
• convalescent serum may not be collected
so that the clinical diagnosis can be
confirmed
• antibiotic therapy may blunt the antibody
response
Chlamydophila psittaci
• The incubation period is about 10 days
• ranges from an 'influenza-like' syndrome,
with general malaise, fever, anorexia, sore
throat, headache and photophobia, to a
severe illness with delirium and
pneumonia.
• tetracyclines or macrolides
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