Chlamydia/Mycoplasma/Legionella Flashcards Preview

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Flashcards in Chlamydia/Mycoplasma/Legionella Deck (32):
1

Chlamydia trachomatis diseases

Eye Trachoma/Neonatal Conjunctivitis/Genital Tract Infection

2

Chlamydia pneumoniae diseases

Respiratory Illness - atypical pneumonia

3

Chlamydia psittaci diseases

Zoonosis from birds that presents as a mild influenzal disease, but can develop into a rapidly severe and fatal pneumonia

4

Mycoplasma pneumoniae diseases

Tracheobronchitis manifested by headache, fever, and malaise, followed 2 – 4 days later by cough

5

Legionella diseases

SHORT INCUBATION
Pontiac Fever–febrileinfluenza-likeillness without respiratory component

LONG INCUBATION
Legionellosis (severe pneumonia)

6

What are the various forms of chlamydia in its life cycle?

Elementary Body - infectious form that is uptaken into the cell via a phagosome

Reticulate Body - this is the reorganized EB after it enters the cell and it divides by binary fission until the entire cell is filled with the organisms

7

What is the major virulence factor of Chlamydia?

Heat Shock Proteins that provokes a potent inflammatory response causing tissue damage, and is the major virulence factor identified.

8

What is the major virulence factor of Mycoplasma?

P1 Protein.

M. Pneumonia attaches to cilia and microvilli lining of bronchial epithelium mediated by cytoadhesion protein called P1. The binding results in a coupling with oligosaccharide receptors, and interferes with ciliary action. An inflammatory response follows similar to that of a superantigen, resulting in desquamation, with resulting infiltration of lymphocytes and plasma cells resulting in thickened walls of bronchial tree.

9

Are Chlamydia intracellular or extracellular bacteria?

Obligate Intracellular bacteria

10

What is the the energy source of Chlamydia?

They are host cell dependent for energy as they produce no ATP

11

What are the manifestations of eye trachoma?

Chronic follicular conjunctivitis, eyelid curling and scarring

12

What immunotypes of C. trachomatis causes trachoma?

A through C

13

What immunotypes of C. trachomatis causes genital tract infection?

D through K

14

What are the manifestations of C. trachomatis genital tract infection?

Males
• Urethritis (males), may be relatively assymp
• Epidymitis, prostatitis (less than 35 yr)

Females
• cervicitis , usually assymptomatic
– salpingitis, PID ; high association with infertility

15

How does C. trachromatis cause infant conjunctivitis?

Contact with vaginal secretions during birth

Most common cause of neonatal conjunctivitis in U.S.

16

What immunotypes of C. trachomatis cause infant conjunctivitis?

D through K

The same as that cause genital tract infection

17

What other infection in neonates is C. trachomatis associated with?

Infant Pneumonia

18

What immunotype of C. trachomatis is associated with lymphogranuloma venereum?

L1, L2 and L3

19

What is a common cause of community pneumonia?

C. pneumonia

20

What is the reservoir of C. psittaci?

Birds like parrots and parakeets

21

What is the main infection of C. psittaci?

Lower respiratory tract infection

22

What is the appearance of M. pneumoniae on cell culture like?

Fried egg

23

What is the pathogenesis of M. pneumoniae?

– smallest organisms that replicate on complex cell free medium
– no cell wall, single triple layered membrane (sterols), requires cholesterol for growth
– divides by binary fission
– fried egg appearance on culture after days
– binds oligosaccharide receptors- adhesion P1

24

What are some other diseases that Mycoplasma may cause?

- Guillain-Barre
- Cardiac
- Skin

25

What is characteristic about the CXR of Mycoplasma infections?

They will be out of proportion with the severity of the infection

26

What Gram is Legionella?

Gram negative. But they do not stain clinically

27

What is the aerobic status of Legionella?

• Obligate aerobe

28

Are Legionella catalase positive or negative?

Catalase positive

29

What is the reservoir of Legionella?

• Lives in water
– Aquatic lakes
– Amplified in man made reservoirs
• Enhanced by warm temperature, stagnation, scale, sediment and commensal algae, protozoa and bacteria

30

What is the pathogenesis of Legionella?

• OMP (porin) binds C3b complement receptor on mononuclear phagocytes
• Endocytosis 􏰁inhibit phagolysosome fusion leading to 􏰁intracellular multiplication
• Kill cell with lysis of vacuole

31

What are the main clinical manifestations of Legionella infection?

Short Incubation • Pontiac Fever–febrile influenza-like illness without respiratory component

Long Incubation • Legionellosis (severe pneumonia)

32

How can Legionella infection be prevented?

- Cooling of water towers
- Superheating of water

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