Respiratory Tract Pathogens Flashcards Preview

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Flashcards in Respiratory Tract Pathogens Deck (35):

What are defining characteristics of Mycobacterum Tuberculosis?

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


How can you identify if someone has TB or not?

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.


What are the specific antigens only produced by TB?

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


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

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.


What are characteristics of active TB?

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


What are latent characteristics of TB?

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


How does latent TB become reactivated?

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


How can drug resistant strains of TB develop?

Patients not being entirely compliant with the antibiotics.


Where is Mycobacterium Leprae usually located?

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


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

Tuberculoidal Leprosy - due to strong cell-mediated response
Lepromatous Leprosy - due to strong humoral response


What are the clinical manifestations of Tuberculoidal leprosy?

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


How is Lepromatous Leprosy different from Tuberculoidal?

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


What is the structure of Legionella?

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


What does Legionella require to grow on media?

Ferric Iron and L-cystein


What is the most common serotype that infect humans?

Legionella Pneumophila serogroup I


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

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


Who does Legionella primarily effect?

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


Within humans where do Legionella reside?

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


What are virulence factors of Legionella?

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


How does Legionella lifecycle change while in the Macrophage?

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.


What are the two forms of Legionellosis?

Legionaire's Disease and Pontiac Fever


What are the differences between the two forms of Legionellosis?

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.


Are people infected with Legionellosis infectious?

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


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

Buffered charcoal yeast extract with a "cut glass" look


What are physical characteristics of Pseudomonas?

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


What are unique properties of P. Aeruginosa infection?

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


Where is Pseudomonas found?

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.


What kind of patient does Pseudomonas common effect?

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


How are CF patients effected by Pseudomonas?

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.


Where does pseudomonas reside in the body?

Extracellular. Does not penetrate cells.


What are common virulence factors of pseudomonas?

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


What are the exotoxins and what do they do?

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


Where are common places Pseudomonas can reside in the body?

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


What are unique characteristics of pseudomonas colony?

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


What does burkholderia cepacia usually cause?

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