1. Diagnostic microbiology lecture: 17 CHLAMYDIA
Abed ElKader Elottol MSc. Microbiology
2010
Abed ElKader ElOttol

2. General Characteristics • Obligate intracellular bacteria.
• Have ribosomes like bacteria.
• Are metabolically deficient.
Morphology
• Small rounded organism.
• Multiply by binary fission.
• Cell wall consists of inner & outer membranes but differ from that of Gram negative bacteria by absence of peptidoglycan.
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3. Cultural Characters Grow in: Yolk sac of chicken embryo
Important Species
C. psittaci
C. pneumoniae
C. trachomatis
Cultural Characters Grow in:
Yolk sac of chicken embryo
Tissue culture (McCoy cells)
PATHOGENESIS
• Infect epithelial cells of mucous membranes & lungs
Virulence is due to:
• Resistance to phagocytic killing by lysosomal enzymes
• Heat-labile toxin
• Competition with host cell for nutrients
• Host’s immune response may account for inflammation & tissue destruction.
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4. Abed ElKader ElOttol

5. A zoonotic respiratory disease. Natural habitat : birds
CHLAMYDIA PSITTACI
A zoonotic respiratory disease.
Natural habitat : birds
Transmitted through inhalation of :
Respiratory secretions & dust from faeces of infected birds
Common in poultry workers
Disease : Pneumonia (Psittacosis)
Diagnosis
Isolation of organism from sputum by tissue culture
Complement fixation test to detect specific Abs
Treatment
Tetracycline in adults
Erythromycin in babies
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6. (TW – Taiwan & AR – acute respiratory)
CHLAMYDIA PNEUMONIAE
Also known as TWAR
(TW – Taiwan & AR – acute respiratory)
Cause atypical pneumonia like Mycoplasma pneumoniae
Treatment
Tetracycline in adults
Erythromycin in babies
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7. CHLAMYDIA TRACHOAMATIS 15 serotypes (A-L)
Transmission: Through close personal contact like:
• Sexual
• Passage through birth canal
• Finger to eye or fomite to eye (Trachoma)
DISEASES
1. Trachoma
• Caused by serotypes A, B, Ba & C
• One of the leading causes of blindness in developing countries with dry & hot weather
• Chronic conjunctivitis : leads to scarring of eye lids and cornea
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8. 2. Genital Tract Infections (Serotypes D-K)
• Non-gonococcal urethritis in men
• A common cause of non-gonococcal urethritis
• Mucopurrulent urethral discharge
• May progress to epidydmitis & orchitis (testes inflamation)
• Cervicitis & Vaginitis
• Mucopurrulent vaginal discharge
• Pelvic Inflammatory Disease (PID)
• May lead to secondary infertility
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9. 3. Neonatal Infections (Caused by serotypes D-K)
• Acquired from mother’s birth canal
• Inclusion Conjunctivitis
• Profuse mucopurrulent discharge 7-12 days after birth
• Pneumonia.
4. Lymphogranuloma Venereum (LGV)
• Caused by serotypes L1, L2 & L3
• A STD with lesions on genitalia & LNs (buboes)
5. Reiter’s Disease
An autoimmune disease caused by Abs formed against C. trachomatis which cross react with antigens on cells of urethra & joints(arthritis, redness of the eyes, and urinary tract signs).
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10. • Specimens from urethra, conjunctiva, sputum & cervix. • Microscopy.
LAB DIAGNOSIS
• Specimens from urethra, conjunctiva, sputum & cervix.
• Microscopy.
• Chlamydial “cytoplasmic inclusions” are detected by:
• Giemsa staining
• Fluorescent Ab staining
• PCR
• Cell Culture
• Sero-diagnosis
TREATMENT
Tetracycline in adults
Erythromycin or Azithromycin in babies
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11. Calymmatobacterium granulomatous
GRANULOMA INGUINALE
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12. The disease is commonly known as donovanosis
Small, painless nodules appear after about 10–40 days of the contact with the bacteria. Later the nodules burst, creating open, fleshy سميك, oozingرشح lesions.
General characteristics
Capsulated short Gram-negative rod
A STD with higher incidence in homosexuals
Clinical Features
Initially papules appear on external genitalia which ulcerate and extend widely – ulcer formation
Base of ulcer is “BEEFY”; spreads by contact so is known as “KISSING ulcers”
Lymph Nodes may enlarge
Treatment : Tetracycline
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13. MYCOPLASMA
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14. GENERAL CHARACTERISTICS
The smallest free-living organism (0.3 μ diameter).
Have no cell wall.
Insensitive to penicillins & cephalosporins.
Poorly stained by Gram-staining.
Cytoplasmic membrane contains cholesterol.
Slow growth on specialized artificial culture media (a week).
Typical “fried-egg” appearance of colonies by a plate microscope
Abed ElKader ElOttol

15. Approximate Formula* Per Liter
Formulae
Difco™ PPLO Agar
Approximate Formula* Per Liter
Beef Heart, Infusion from 50 g g
Peptone g
Sodium Chloride g
Agar g
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16. MYCOPLASMA PNEUMONIAE MAIN DISEASE • Primary atypical pneumonia
• Common in late summer and early autumn
PATHOGENESIS & EPIDEMIOLOGY
• Droplet infection.
• Organism adhere to respiratory epithelium.
• Inhibit ciliary motion.
• Damage epithelium.
• Common in chidren & young adults
• Increased incidence in winter
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17. Sore throat, fever & headache.
CLINICAL FEATURES
Sore throat, fever & headache.
Cough with small amount of whitish non-purulent sputum.
Some extrapulmonary symptoms.
Opacities on chest X-Rays.
IMMUNITY
Incomplete: second episode can occur.
Abed ElKader ElOttol

18. UREAPLASMA URELYTICUM
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19. • Non-gonococcal, non-chlamydial urethritis in men.
Differentiated from mycoplasma due to urease enzyme production Like mycoplasma produce “fried egg” colonies on specialized medium.
Diseases
• Non-gonococcal, non-chlamydial urethritis in men.
• Post-partum fever in women.
• Transmitted by sexual contact.
MYCOPLASMA & UREPLASMA
LAB DIAGNOSIS
Culture : “Fried egg” colonies on specialized medium
Cold Agglutinin detection A titer of 1:128 or higher – indicates recent infection
TREATMENT
Tetracycline OR Spectinomycin
Abed ElKader ElOttol

20. RICKETTSIA & COXIELLA
Abed ElKader ElOttol

21. Rickettsiae
A genus of small, rod-shaped, round to pleomorphic microorganisms .
gram-negative
cultivable only in living tissues.
Transmitted by liceقمل and ticksقراد, they cause disease in humans and domestic animals but are also found in the cytoplasm of tissue cells of lice, fleas, ticks and mitesسوس , which may act as reservoirs and vectors

22. Transmission Biological Mechanical Examples
Ticks
Sucking lice
Live inside arthropods for months
Mechanical
Instruments
Blood transfusions
Live short time outside of host

23. Pathogenesis
Insect vectors for human transmission: arthropods such as fleas, ticks, mites عث, or lice
Rodents, humans, or arthropods: all can serve as reservoirs
Multiply in salivary glands of ticks & gut of lice/fleas
Site of Bite = Eschar (encrustedمتقشر ulcer) → necrotic tissue:

24. Site of bite = point at which Rickettsia enters the body becomes blackened
Following bite, organisms taken into body by “phagocytosis process
Organisms multiply in both nucleus & cytoplasm of host cell.

25. Typhus Group
Louse borne (epidemic) Typhus.
Etiological agent = Rickettsia prowazekii
Transmission: person-to-person by infected human body louse that excretes organisms in feces
Introduction of pathogen form lice facilitated by scratching the louse bites
high fever, chills, rash possible
Duration of Disease: ~2 weeks; more severe in ederly
Complications: CNS dysfunction and myocarditis

26. Rock Mountain Spotted Fever
Etiological agent = Rickettsia ricketsii
Reservoir = rodents (mice, rats)
Vector = Tick Bite
Rickettsia in saliva of tick, transfer to humans after bite Human infection
High fever & malaise, then rash – initially, but becomes petechial or hemorrhagic
Rash starts on extremities, then rapid spread to entire body.
Untreated cases – vascular disturbances with myocardial or renal failure possible

27. Coxiella Etiological agent = Coxiella burnetti Q fever
Reservoir = cattle, sheep, rodents, ticks
Vector = contaminated aerosol
C. burnetti enters the body via mucous membranes, abrasions & GIT via consumption of milk for infected animals
Zoonosis becouse animal direclty transmits the organism to humans
high fever, cough, pneumonia, hepatitis – all self-limiting usually; rarely – endocarditis (scarring of hrt. valves) and scarring of liver
complicated by hepatitis, myocarditis, or encephalitis

28. Growth characteristics • Grow only in eukaryotic cell like
• Tissue cultures OR embryonated eggs •
Abed ElKader ElOttol

29. RICKETTSIA & COXIELLA : LAB DIAGNOSIS • Serology • PCR
• Tissue culture
• Weil-Felix Reaction
• Antigens of several species of Rickettsiae cross-react with cell wall O antigen of Proteus OX-2, OX-19, OX-K.
• These Proteus antigens can be used in lab to detect presence of specific antibodies against certain Rickettsia in patients serum.
• Reaction negative in Q fever
TREATMENT
• Tetracycline
• Chloramphenicol
Abed ElKader ElOttol

30. End of Lecture
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