Respiratory Tract Pathogens

Question 1

What are defining characteristics of Mycobacterum Tuberculosis?

Answer 1

Unusual cell wall made up of complex lipids, doesn’t gram stain, Acid-Fast Method, very slow growing, and Mycolic Acids on surface. (Gram +)

Question 2

How can you identify if someone has TB or not?

Answer 2

PPD skin test, can identify if you have antibodies to cell products of TB, but cannot determine if it is Active or Latent infection. Will also be positive if the person was vaccinated.

Question 3

What are the specific antigens only produced by TB?

Answer 3

ESAT-6 and CFP-10, specific antigens made by TB to determine if someone has TB or not.

Question 4

What determines what form TB takes after infecting someone? Who are most susceptible?

Answer 4

Depends on the immunocompentency of the individual, the more compromised they are the higher the chance they will develop an active form rather than latent. HIV patients high likelihood.

Question 5

What are characteristics of active TB?

Answer 5

Night Sweats, Productive Cough, weight loss, malaise, and infectious to transmit the organism. Abnormal CXR. Positive sputum stain with Acid-Fast.

Question 6

What are latent characteristics of TB?

Answer 6

Granulomas (immune system surrounded the infection), noninfectious, no visual signs on CXR, and positive PPD skin test.

Question 7

How does latent TB become reactivated?

Answer 7

Typically happens when the patient’s immune system or parts becomes suppressed, allows for reactivation of TB.

Question 8

How can drug resistant strains of TB develop?

Answer 8

Patients not being entirely compliant with the antibiotics.

Question 9

Where is Mycobacterium Leprae usually located?

Answer 9

South US, after direct contact with secretions or inhalation of the bacterium.

Question 10

What are the two kinds of Mycobacterium Leprae how are they caused?

Answer 10

Tuberculoidal Leprosy - due to strong cell-mediated response

Lepromatous Leprosy - due to strong humoral response

Question 11

What are the clinical manifestations of Tuberculoidal leprosy?

Answer 11

Bacterii are located in the nerves causing extensive peripheral nerve damage, SENSORY LOSS, and enlargement of nerves. Not infectious, little bacterii in tissues.

Question 12

How is Lepromatous Leprosy different from Tuberculoidal?

Answer 12

Many plaques in tissues causing extensive lesions and tissue damage. Nerve involvement, but no sensory loss. Very infectious.

Question 13

What is the structure of Legionella?

Answer 13

Gram Negative, Obligate aerobes, unencapsulated rods, with a single flagella. Break down Amino Acids rather than carbohydrates.

Question 14

What does Legionella require to grow on media?

Answer 14

Ferric Iron and L-cystein

Question 15

What is the most common serotype that infect humans?

Answer 15

Legionella Pneumophila serogroup I

Question 16

Where do legionella come from and how do they infect humans?

Answer 16

They live within Amoeba in water and humans can ingest them by drinking or inhalation from the air.

Question 17

Who does Legionella primarily effect?

Answer 17

Opportunistic organism, elderly, recent surgery, and immunocompromised individuals.

Question 18

Within humans where do Legionella reside?

Answer 18

The bacterii live within Macrophages preventing the Phagosome-Lysosome fusion (preventing them from being degraded). Coiling Phagocytosis.

Question 19

What are virulence factors of Legionella?

Answer 19

Cytotoxins, Hemolysis, Proteases, Endotoxins, Lipase, and IV Secretion system.

Question 20

How does Legionella lifecycle change while in the Macrophage?

Answer 20

When the bacterii are dividing and nutrients are plentiful they are nonmotile, but when nutrients begin to run out they become motile in order to escape the cell to infect another.

Question 21

What are the two forms of Legionellosis?

Answer 21

Legionaire’s Disease and Pontiac Fever

Question 22

What are the differences between the two forms of Legionellosis?

Answer 22

Legionaire’s Disease develops after 2-14 days is 5-40% Fetal, CXR = Pneumonia, cough, fever, chest pain.
Pontiac Fever, is self-limited 24-48 hours after exposure, flu-like illness.

Question 23

Are people infected with Legionellosis infectious?

Answer 23

No. There is no human to human transfer. Must come from the source.

Question 24

What kind of media does Legionella grow on and how does it look?

Answer 24

Buffered charcoal yeast extract with a “cut glass” look

Question 25

What are physical characteristics of Pseudomonas?

Answer 25

Gram Negative rods with polar flagella, Oxidase Positive. Highly resistant to chemical disinfection.

Question 26

What are unique properties of P. Aeruginosa infection?

Answer 26

Highly Adaptive, Hemolytic, PRODUCE PIGMENT (pyoverdin/pyocanin), produces unique color and grape smell when culturing it.

Question 27

Where is Pseudomonas found?

Answer 27

Found Everywhere in environment. Opportunistic organism. Frequently in biofilms on plastic equipment in hospitals and devices. Create matrix on the object preventing abx from penetrating.

Question 28

What kind of patient does Pseudomonas common effect?

Answer 28

Patients who have their physical barrier disrupted, puncture wounds and burn victims. Additionally Cystic Fibrosis patients.

Question 29

How are CF patients effected by Pseudomonas?

Answer 29

Typically as the CF patient ages they accumulate more chronic pseudomonas colonization, early years mostly staph and haemophilus. Pseudomonas can make Mucoids in their lungs protecting them from elements surviving in their thick mucous.

Question 30

Where does pseudomonas reside in the body?

Answer 30

Extracellular. Does not penetrate cells.

Question 31

What are common virulence factors of pseudomonas?

Answer 31

Adhesions, Polysaccharide capsule, endotoxins, pigments, exotoxins, and proteases.

Question 32

What are the exotoxins and what do they do?

Answer 32

ExoA - inhibits protein synthesis, ExoS, Elastase; type IV secretion can be used to inject

Question 33

Where are common places Pseudomonas can reside in the body?

Answer 33

On any indwelling device (catheter, G-tube, contacts, ET tube), wounds, GU, and lungs.

Question 34

What are unique characteristics of pseudomonas colony?

Answer 34

Colony size, pigmentation, hemalytic activity, and grape/wine odor. More resistant than most bacteria to antibiotics usually use multiple.

Question 35

What does burkholderia cepacia usually cause?

Answer 35

A type of pseudomonad. Causes infection from catheters and IV lines.