1. CHLAMYDIA, RICKETTSIA
AND MYCOPLASMA

2. Biological Agents/Diseases APPROVED CDC LIST (2003)
(FEDERAL BIODEFENSE & BIOTERRORISM)
CATEGORY A
» Anthrax (Bacillus anthracis)
» Botulism (Clostridium botulinum toxin)
» Plague (Yersinia pestis)
» Smallpox (variola major)
» Tularemia (Francisella tularensis)
» Viral hemorrhagic fevers (filoviruses [e.g., Ebola, Marburg] and arenaviruses [e.g., Lassa, Machupo])
CATEGORY B
» Brucellosis (Brucella species)
» Epsilon toxin of Clostridium perfringens
» Food safety threats (e.g., Salmonella species, Escherichia coli O157:H7, Shigella)
» Glanders (Burkholderia mallei)
» Melioidosis (Burkholderia pseudomallei)
» Psittacosis (Chlamydia psittaci)
» Q fever (Coxiella burnetii)
» Ricin toxin from Ricinus communis (castor beans)
» Staphylococcal enterotoxin B
» Typhus fever (Rickettsia prowazekii)
» Viral encephalitis (alphaviruses [e.g., Venezuelan equine encephalitis, eastern equine encephalitis, western equine encephalitis])
» Water safety threats (e.g., Vibrio cholerae, Cryptosporidium parvum
CATEGORY C
» Emerging infectious diseases such as Nipah virus and hantavirus

3. I. CHLAMYDIA IS THE PROTOTYPE OBLIGATE INTRACELLULAR PATHOGEN
FOUR SPECIES: NATURAL HOSTS:
1. C. trachomatis: humans, mice and pigs
2. C. pneumoniae : humans and horses
3. C. psittaci: birds, mammals and humans
4. C. pecorum: cattle and sheep

4. CHLAMYDIA LIFE CYCLE

5. ELEMENTARY BODY OF CHLAMYDIA

6. ELECTRON MICROSCOPY OF CHLAMYDIA LIFE CYCLE

7. Properties of Chlamydial Particles
Property
Elementary body
Reticulate body
Size
0.2 – 0.4 μm
0.6 – 1.0 μm
Rigid cell wall
Yes No
Extracellular stability
Infective
Induces phagocytosis
Inhibits phagosome
fusion with lysosome
Toxic
Metabolic activity
Replication

8. II. MEDICALLY IMPORTANT SPECIES

9. III. CHLAMYDIA TRACHOMATIS
There are at least 19 serovars (A-L)
Different serovars are associated with distinct clinical signs
Endemic trachoma is associated with serovars:
A, B, Ba, and C
Sexually transmitted disease (STD) is associated with serovars:
D, Da, E, F, G, Ga, H, I, Ia, J, & K (D-K)
Lymphogranuloma venereum (STD) is associated with serovars:
L1, L2, L2a, and L3 (L1-L3)

10. CHLAMYDIA TRACHOMATIS
INCLUSION BODIES

11. CHLAMYDIA TRACHOMATOUS
Trachoma: Later stage of the formation of trachomatous pannus

12. Women Men Increased susceptibility to HIV PID Cervical Infection
(Usually assymptomatic)
Ectopic pregnancy
Fallopian tube
Infertility
Infection of infant
Pneumonia
Self-limiting
eye infection
(Conjunctivitis)
Painful urination
(discharge)
Men
Urethral infection
(Non-gonorrheal urethritis)
May be assymptomatic
Reactive arthritis
May cause Reiter’s syndrome
(Usually in men)

13. REITER’S SYNDROME
Genital lesions, Conjunctivitis, papules on soles of feet, Arthritis

14. CHLAMYDIA TRACHOMATIS SEROVARS L1, L2, & L3
LYMPHOGRANULOMA VENEREUM: Enlarged and ulcerative inguinal lymph node

15. IV. CHLAMYDOPHILA PSITTACI
Primarily a pathogen of birds, elementary bodies are excreted in
droppings.
Humans inhale elementary bodies, causing a flu-like illness
(“parrot fever”- ornithosis)
After an incubation period of 5 to 14 days the human develops
headache, high fever, chills, malaise, myalgia, pulmonary consolidation,
and nonproductive cough.
Often dissemination to CNS. May cause encephalitis.
Occasionally leads to death.
Diagnosis is usually made by serology.
Treatment with either Tetracyclines or erythromycin

16. V. CHLAMYDOPHILA PNEUMONIAE
Human to human transmission (No animal reservoir)
Causes bronchitis, pneumonia and sinusitis.
Infection in humans very common with several hundred thousand
cases each year in the US.
Causes a mild to severe “atypical pneumonia” similar to those
caused by Mycoplasma pneumoniae and Legionella.
Diagnosis by serology and by specific PCR.
Tetracyclines and erythromycin are drugs of choice.
A lot of published data suggest an etiologic association
with atherosclerosis and coronary artery disease
(Still in question). The organisms are ubiquitous.

17. AND RICKETSIA-LIKE ORGANISMS
VI. RICKETTSIAE
AND RICKETSIA-LIKE ORGANISMS
ALL of these organisms are:
Small Gram negative coccobacilli
Obligate intracellular pathogens
Arthropod borne
With the exception of one group all
have a non-human host and are zoonotic
5. They are all susceptible to Tetracyclines

19. VII. RICKETTSIA & ORIENTIA
Typhus and Spotted fevers
These organisms are divided into distinct groups:
The spotted fever group with many species
The most important species is Rickettsia rickettsii
The etiology of ROCKY MOUNTAIN SPOTTED FEVER
The typhus Group:
Rickettsia prowazekii causes epidemic typhus
Rickettsia typhi causes murine typhus
The scrub typhus group:
Orientia tsutsugamushi causes scrub typhus

24. VIII. COXIELLA BURNETII: Q-FEVER

25. IX. EHRLICHIA An Emerging Pathogen (Many Species)
These are small Gram Negative rods
(Rickettsia-like)
They are obligate intracellular pathogens of either monocytes
or PMNs but NOT erythrocytes
(3 groups) All but one species are arthropod borne.
E. sennetsu (restricted to Japan) causes disease in humans
from eating raw fish
Most species are transmitted from mammals to humans
by ticks: Zoonoses).
At least 3 forms of human disease (All are febrile illnesses):
Sennetsu
Human Monocytic Ehrlichiosis
Human Granulocytic Ehrlichiosis
Diagnosis can be difficult, best made using either serology or
species specific DNA probes.

26. X. MYCOPLASMA UREAPLASMA & L-Forms

27. XI. MYCOPLASMA PNEUMONIAE