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30 Cards in this Set
- Front
- Back
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What are 6 agents of community-acquired pneumonia?
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1.Strep pneumoniae
2.Legionella 3.H. influenzae 4.Mycoplasma pneumoniae 5.S. aureus 6.Chlamydia pneumoniae |
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How does Pseudomonas stain? Where is it found in the environment?
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*G- rod
*ubiquitous in environment |
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What agent is most closely associated with ventilator-associated pneumonia?
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Pseudomonas
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What causes the blue-green color often seen with Pseudomonas?
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Pyocyanin
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Describe the mucoid morphotype of pseudomonas seen in CF patients. Why is it so hard to eradicate? What causes damage to the lung tissue?
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*able to form and grow in a mucoid biofilm which makes it difficult to eradicate
*heavy PMN activity inflicts tissue damage *cycle of repeated chronic infections |
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T/F:
Pseudomonas is generally amenable to treatment with PCN. |
False: Pseudomonas has multiple drug resistance issues.
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How does H. influenzae stain? What are its culture characteristics? Where can it be found normally?
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*G- rod
*will not grow on SBA or MAC due to NAD+ requirements *normal flora of the URT |
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Name 3 forms of invasive disease caused by H. influenzae. What serotype is usually responsible for these conditions?
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1.epiglottitis
2.meningitis 3.bacteremia *Type b |
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The vaccine for H. influenzae is a conjugated protein vaccine. What population is afforded protection as a result of conjugation? Why?
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*children under 2 yrs
*they are otherwise unable to generate a T-dependent response against a polysaccharide immunogen |
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What common childhood condition can be caused by nontypable H. influenzae?
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Otitis media
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How does Mycoplasma pneumoniae stain?
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It does not accept a Gram stain because it lacks a cell wall.
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How is M. pneumoniae transmitted? How is the bug able to colonize the epithelia?
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*p-p by aerosol secretions
*use a specialized attachment tip to adhere to respiratory cilia |
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Does M. pneumoniae invade host cells? What is a virulence factor it produces?
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*it remains extracellular
*produces cmpds (e.g. H2O2) that inhibit ciliary beating |
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M. pneumoniae causes walking pneumonia - what are the symptoms of this? In what part of the lungs does it occur?
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*cough, fever, low sputum production
*ltd to bronchial mucosa - no lobar or alveolar involvement |
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Because of its ubiquitous nature, M. pneumoniae can be hard to identify as a pathogen. What is one test that can be used to ID it?
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*cold agglutins
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Which would be the better treatment for M. pneumoniae - PCN-G or erythromycin? Why?
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Erythromycin - the bug lacks a bacterial cell wall, thus B-lactams would be highly ineffective.
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How does Bordetella stain? What are its growth characteristics in culture?
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*G- rod
*grows only on specialty agar *yields "mercury colonies" |
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Which is more contagious - bordatella or legionella?
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Bordatella is highly contagious whereas there is no p-p spread for legionella.
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What are of the body does bordatella colonize?
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Ciliated epithelium of nasopharynx.
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What are the 3 stages of infection with bordatella? What are the symptoms of each? How long does each last?
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1.Catarrhal: URI symptoms; 1-2 wks
2.Paroxysmal: mucus accumulation, coughing fits; 2 wks 3.Convalescent: decreased coughing; <8 wks |
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Does bordatella penetrate the host cells? What are some virulence factors it produces?
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*colonize mucosal surface and do not penetrate
*pertussis toxin: ADP-ribosylates G-protein to activate adenylate cyclase *tracheal cytotoxin: destroys cilia and ciliated cells |
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What causes the "whoop" seen in whooping cough?
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Bordatella colonizes the mucosal surface and destroys cilia. Pts are unable to clear respiratory secretions and mucus and this leads to violent paroxysms of coughing followed by a sharp inspiration.
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What might be abnormal about the CBC of a pt infected with bordatella?
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This infection causes lymphcytosis so a large number of WBC would be expected.
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Is Bordatella typically fatal?
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No; but it can be for patients with underlying heart or pulmonary conditions.
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What type of vaccine is in use for bordatella? Has this always been the case?
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*an acellular vaccine of purified protein filtrates is currently in use
*this replaced a whole cell attenuated vaccine removed for publlicity purposes |
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Where might legionella be found in the environment? How is it acquired?
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*aqueous environments
*inhalation of droplets |
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How is Legionella able to survive in macrophages? Whta kind of immune response is required to clear the infection?
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*prevents fusion of phagosome with lysosome and acidification
*T-cell mediated; also TNF-a which inhibits intracellular growth |
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What are the symptoms of Legionnaire's disease?
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*flu-like symptoms develop into pneumonia
*NO cough or sputum *N/V/D fairly common *low PO2 |
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What are the symptoms of Pontiac Fever? What treatment is recommended?
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A mild flu that is self-ltd. No treatment recommended.
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How is infection with Legionella usually diagnosed?
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*Culture is difficult
*clinical findings *urine Ag test |
