Chlamydia, Rickettsia Coxiella, and Barton Ella 06-07

Obligate Intracellular and
Nonculturable Agents
Obligate Intracellular and Nonculturable
Agents
• Chlamydia
• Calymmatobacterium granulomatous
• Rickettsia
• Coxiella, and
• Bartonella
Objectives
• To know the major diseases associated with each species of Chlamydia

and their clinical presentation
• To know the mode of transmission for Chlamydia Rickettsia, Coxiella,

and Bartonella.
• To know the appropriate cultures for detection of C. trachomatis.
• Clinical Diagnosis of the Chlamydiam, Rickettsia,

Coxiella, and Bartonella
• To know the serological investigation
• Antimicrobial therapy
CHLAMYDIA
•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.
• Elementary body (EB) has an outer membrane similar to that of many

Gram-negative bacteria.
•The most prominent part of this membrane is Major Outer Membrane

Protein (MOMP).
•The MOMP is a transmembrane protein that contain species-specific

epitope that can be known by monoclonal antibodies
CHLAMYDIA
Important Species
• C. trachomatis
• C. pneumoniae
• C. psittaci
Cultural Characters
Grow in:
• Tissue culture (McCoy cells)

• Yolk sac of chicken embryo
Reproduction Cycle of Chlamydia
Human Cell
Extracellular Infectious Development to

Elementary Bodies (EB) Reticulate Bodies (RB)
Attachment &
Phagocytosis of EB
Release of EB
Multiplication of RB
by binary fission
Multiplication stops
Continued multiplication & and

reorganization of RB into EB.
Development of a large
Cytoplasmic inclusion
CHLAMYDIA
PATHOGENESIS
• Infect epithelial cells of mucous membranes &
lungs
Virulence is due to:

• Resistance to phagocytic killing
• Heat-labile toxin
• Competition with host cell for nutrients
• Host’s immune response as inflammation & tissue
destruction
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
• Trachoma is a chronic follicular
inflammation of the eye lid and
increased vascularization of the
corneal conjunctiva followed by
scarring of eye lids and cornea
• Caused by serotypes A, B, Ba & C
• One of the leading causes of blindness
in developing countries with dry & hot
weather
DISEASES
2. Genital Tract Infections (Serotypes D-K)
o Non-gonococcal urethritis in men
• A common disease
• Mucopurrulent urethral discharge
• May progress to epidydmitis & orchitis
o Cervicitis & Vaginitis
• Salpingitis (5-30%)
• Mucopurrulent vaginal discharge
o Pelvic Inflammatory Disease (PID)
• May lead to secondary infertility
DISEASES
3. Neonatal Infections (Caused by serotypes D-K)
• Acquired from mother’s birth canal
o Inclusion Conjunctivitis
• Profuse mucopurrulent discharge 7-12 days after birth
o 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 Ags on cells of urethra
& joints
LAB DIAGNOSIS
Specimens from urethra, conjunctiva, sputum & cervix
3. Microscopy
Chlamydial “cytoplasmic inclusions” are detected by:
• Giemsa staining
• Immunofluorescence
7. Cell Culture : McCoy cell line
8. Nonculture
• Enzyme immunoassay
• Amplified Nucleic acid probes/amplification
11.Sero-diagnosis (antibody detection) very limited and
problematic
TREATMENT
• Tetracycline in adults
• Erythromycin/Azithromycin in children
CHLAMYDIA PNEUMONIAE
• A cause of walking pneunoniae
• Also known as TWAR
(TW – Taiwan & AR – acute respiratory)
• Cause atypical pneumonia like Mycoplasma
pneumoniae
• Infection with C. pneumoniae has been
established as a risk factor for Guillain-Barre
syndrome.
Treatment
CHLAMYDIA PSITTACI
• A zoonotic respiratory disease
• Natural reservoir : birds
Transmitted through inhalation of :
• Respiratory secretions &
• Dust from feces of infected birds
• Common in poultry workers
Disease : Pneumonia (Psittacosis), (ornithosis) ( parrot
fever)
Diagnosis
• Isolation of organism from sputum by tissue culture
• Complement fixation test to detect specific Abs
Treatment
Epidemiologic association between chlamydial species, strain, and
diseases
Species Serovars Modes of Diseases
(Strains) transmission
C. Trachomatis A,B,Ba, C Hand to eye, fomites, Trachoma
flies
C. trachomatis B, Ba, D-K Sexual, hand to eye Inclusion
conjunctivitis,
genital infection
C. trachomatis L1, L2, L3 Sexual Lymphogranul-

oma venereum
LGV
C. psittaci Many Aerosal Psittacosis
C. pneumoniae TWAR Human to human Respiratory

infection
Calymmatobacterium granulomatous
Causes GRANULOMA INGUINALE

• 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”
• LN may enlarge
Treatment : Tetracycline
RICKETTSIA
• Are obligate intracellular parasites

• Rapidly loss infectivity outside host cell
• Growth slow compared to bacteria
• Have animal reservoirs (zoonotic diseases)
• Humans are accidental host in most cases
Transmission
• Maintained in arthropods like ticks, lice, fleas & mites
• Usually transmitted to human by bite of vector
Diseases
• Spotted fever group: in North and South America, causes Rocky
mountain spotted fever (RMSF)
• Epidemic typhus group In Asia, Africa and causes epidemic
typhus
RICKETTSIA & COXIELLA : DISEASES
Disease Organism Vector
1. Rocky mountain R. rickttsii Ticks
Spotted fever
2. Epidemic typhus R. prowazeki Lice
3. Q fever C. burnetti None

(cattles, sheeps)
Clinical Features
• History of arthropod vector bite
• Acute onset of fever, myalgias, headache
• Skin rashes due to vasculitis
Pathogenesis
• Rickettsiae infect the vascular

endothelium and the primary lesion is
vasculitis in which rickettsiae multiply in
the endothelial lining the blood vessels
PATHOGENICITY OF RICKETTSIA
Bacteria infect Blockade of small

vascular blood vessels
endothelium & skin rashes
Enter cells by Vasculitis &

endocytosis Thrombosis
Multiply Infection of
within cell other cells
Release of
Host cell lysis
rickettsia
Clinical picture
Early signs and symptoms
• fever, nausea, vomiting,

severe headache, muscle
pain, lack of appetite.
• The rash first appears 2-5
days
• Most often it begins as small,
flat, pink, non-itchy spots
(macules) on the wrists,
forearms, and ankles. These
spots turn pale when
pressure is applied and
eventually become raised on
the skin.
• Later Signs and
Symptoms
• Late (petechial)
rash on palm and
forearm
• abdominal pain, joint
pain, diarrhea.
Lab Diagnosis
 Indirect immunoflourescence assay (IFA)
Other well assays including ELISA, latex agglutination..
•Most patients demonstrate increased IgM titers by the end of

the first week of illness.
• Diagnostic levels of IgG antibody generally do not appear until 7-

10 days after the onset of illness.
• IgG antibodies are more specific and reliable since other

bacterial infections can also cause elevations in riskettsial IgM
antibody titers.
 PCR which can detect DNA present in 5-10 rickettsiae in a

sample, this procedure is more specific than antibody-based
methods
IFA reaction of a positive human serum
Gimenez stain of tick hemolymph cells
on Rickettsia rickettsii grown in chicken yolk
infected with R. rickettsii
sacs, 400X
Coxiella burnetii
• Causative agent of Q fever
• Zoonotic disease for cattle sheep and goats
• In infected animals organisms are shed in urine, faces, milk and birth
product
• Human are infected by inhalation of the contaminated aerosols
• IP 2-4 weeks
Clinical manifestaions:
• fever,
• Atypical pneumoniae,
• Hepatitis,
• Endocarditis, bone and CNS infection
Morphology
• Coccobacilli
• Stained poorly with Gram-staining
• Growth on tissue cultures
• Detected by using a direct immunofluorencet assays
Serology is the most convenient and commonly used diagnostic tool
Treatment of choice is tetracycline
RICKETTSIA & COXIELLA : LAB DIAGNOSIS
• Serology
• PCR
• Tissue culture
• Treatment
o Tetracycline
o Chloramphenicol
Bartonella
Bartonella quintana:
causes trench fever
• History of louse contact, patient present with
fever, head ache relapsing fever and rash.
• Associated with alcoholism
Bartonella hensela:
causes Cat Scratch Fever (CST)
• Common in children
• Persistent lymphadenitis is the usual finding
• AID and other immunocompromised states
are associated with more severe infections
Case study
A 7-day-old newborn was brought by his

grandmother to the emergency department of
a large city hospital. He had been discharged
3 days after birth. On admission he had fever
of 390C, loss of appetite, perfuse yellow
discharge from the right eye, and general
irritability. Past medical history revealed the
mother to be a 17-year-old intravenous drug
abuser with no prenatal care, who had a
vaginal delivery in the parking lot of a local
hospital. The eye discharge was cultured for a
variety of organisms and was diagnosed.
Learning assessment questions
• What organisms should be considered as a possible
causes of neonatal conjunctivitis?
• What stain should be performed on the discharge or
conjunctival scraping for microscopy examination?
• For the infant described in the case study, what
other clinical conditions could be due to the causative
organisms?
• What are the more common sites of infection in
newborns infected with this organism?
• What STD is caused by C. trachomatis serotypes L1,
L2, and L3?
• Which chlamydia species is associate Guillain-Barre
syndrome?
• What is psittacosis?
• How is this condition usually diagnosed?

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Obligate Intracellular and

• To know the major diseases associated with each species of Chlamydia

• To know the mode of transmission for Chlamydia Rickettsia, Coxiella,

• To know the appropriate cultures for detection of C. trachomatis.

• Clinical Diagnosis of the Chlamydiam, Rickettsia,

• To know the serological investigation

• Cell wall consists of inner & outer membranes.

• Elementary body (EB) has an outer membrane similar to that of many

•The most prominent part of this membrane is Major Outer Membrane

•The MOMP is a transmembrane protein that contain species-specific

• Tissue culture (McCoy cells)

Extracellular Infectious Development to

Continued multiplication & and

Virulence is due to:

• Passage through birth canal

• Finger to eye OR fomite to eye (Trachoma)

4. Lymphogranuloma Venereum (LGV)

C. trachomatis L1, L2, L3 Sexual Lymphogranul-

C. psittaci Many Aerosal Psittacosis

C. pneumoniae TWAR Human to human Respiratory

Causes GRANULOMA INGUINALE

• Are obligate intracellular parasites

2. Epidemic typhus R. prowazeki Lice

3. Q fever C. burnetti None

• Rickettsiae infect the vascular

Bacteria infect Blockade of small

Enter cells by Vasculitis &

Early signs and symptoms

• fever, nausea, vomiting,

 Indirect immunoflourescence assay (IFA)

Other well assays including ELISA, latex agglutination..

•Most patients demonstrate increased IgM titers by the end of

• Diagnostic levels of IgG antibody generally do not appear until 7-

• IgG antibodies are more specific and reliable since other

 PCR which can detect DNA present in 5-10 rickettsiae in a

A 7-day-old newborn was brought by his

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