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67 Cards in this Set
- Front
- Back
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What are the causes of community acquired pneumonia?
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Streptococcus pneumoniae
Haemophilus influenzae Klebsiella pneumoniae Staphylococcus aureus Pseudomonas aeruginosa Mycoplasma pneumoniae |
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What are the characteristic features of S. pneumoniae?
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Gram positive, lancet-shaped diplococci, α-hemolytic, catalase negative
Normal oropharyngeal flora in 40-70% of patients, binds to fibronectin |
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What is the most common cause of community acquired pneumonia?
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Streptococcus pneumoniae
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Which organism causes lobar pneumonia in infants, elderly, immunocompromised patients, sick cell patients, and chronic alcoholics?
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Streptococcus pneumoniae
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What are the virulence factors for S. pneumoniae?
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Capsule - inhibits phagocytosis
IgA protease - inhibits mucosal defense Pneumolysin Hydrogen peroxide Neuraminidase |
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What is the most significant pathogen in community acquired deaths?
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S. pneumoniae
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What are the characteristics of H. influenzae?
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Gram negative rods
X (hemin) and V (NAD) factors Chocolate agar 2nd MCC of bacterial CAP |
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What are the risk factors for H. influenzae infection?
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COPD
HIV infection Nursing home residents Influenza |
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What are the characteristic features of Klebsiella pneumoniae?
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Non-motile, gram negative rod, encapsulated
CAP or nosocomial infections Lactose fermenter (MacConkey) |
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What are the risk factors for Klebsiella pneumoniae infection?
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Elderly (CAP)
Alcoholism (2/3 of cases) Diabetes COPD |
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Which organism produces mucoid "currant jelly" sputum?
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Klebsiella pneumoniae
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What are the virulence factors for Klebsiella pneumoniae?
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Capsulated, LPS
Blocks phagocytosis and inhibits complement fixation |
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What are the characteristic features of Staphylococcus aureus?
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Gram positive cocci, grow in clusters
β-hemolytic, catalase +, coagulase + |
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What can S. aureus cause?
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CAP, HAP (hospital-associated pneumonia), VAP (ventillator-associated pneumonia), or HCAP (healthcare-associated pneumonia)
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What are the virulence factors for Staphylococcus aureus?
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TSST-1, Protein A, Coagulase, Cytolytic toxins, Teichoic acid
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Why is protein A a virulence factor?
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It binds to Fc on immunogobulins, thus preventing phagocytosis
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What are the risk factors for Staph aureus infection?
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Influenza infection (neuraminidase facilitates binding)
Ventilator use Cystic fibrosis Endocarditis in IV drug users Young age Debilitated Nursing home resident Neutropenia |
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What are the characteristic features of Pseudomonas aeruginosa?
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Gram negative rod
Aerobic, oxidase +, motile Produces pigments |
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To which organism are cystic fibrosis, neutropenic, and burn patients most susceptible?
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Pseudomonas aeruginosa
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What is the most common cause of nosocomial pneumonia?
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Pseudomonas aeruginosa
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What are the virulence factors for Pseudomonas?
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Adhesins, Invasins:
Exotoxin A & exoenzyme S Pyocyanin - cytotoxic to epithelial and endothelial cells Alginate (defensin) - allows for biofilm production |
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What is the mechanism of exotoxin A and exoenzyme S?
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ADP ribosyl transferases
Inactivate EF2 & interfere with protein synthesis |
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What pattern of lung injury does Pseudomonas cause?
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Bronchial pneumoniae
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What are the 3 major bacterial pathogens that cause interstitial pneumonitis?
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Mycoplasma
Chlamydia pneumoniae Legionella (Coxiella and Chlamydia psittaci cause similar clinical disease) |
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Which cause of bacterial interstitial pneumonitis is the most severe?
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Legionella
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What are the characteristic features of Mycoplasma pneumoniae?
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Smallest free-living bacteria that are capable of causing human disease
Lack a cell wall Outbreaks may occur at schools, universities and military training camps |
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50% of patients infected with which organism have cold hemagglutinins?
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Mycoplasma pneumoniae
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Which bacterium is an obligate intracellular parasite and morphologically similar to gram negative bacteria?
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Chlamydia
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What is the infectious but metabolically inert form of Chlamydia in its biphasic life cycle?
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Elementary body (EB)
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Chlamydia
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Receptor-mediated endocytosis
Accumulate in inclusion body Inhibits lysosomal fusion |
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What is the metabolically active form of Chlamydia?
How does it replicate? |
Reticulate body (RB)
They replicated via binary fission, condense into EBs and the cell bursts |
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With respect to the inclusion bodies formed by Chlamydia, where are the reticulate bodies located?
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At the periphery
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What are the three species of Chlamydia that infect humans?
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Chlamydia trachomatis
Chlamydia pneumoniae Chlamydia psittaci |
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Which species of Chlamydia causes disease of the eye?
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Chlamydia trachomatis
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What infection causes neonatal pneumonia via transmission from mother during delivery through the birth canal?
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Chlamydia trachomatis
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Legionella pneumophila
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Gram negative, small aerobic rods
Facultative intracellular organisms that proliferate and destroy phagocytes |
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What are the sources of Legionella?
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Inhaled aerosolized water from contaminated cooling towers, air conditioners, humidifiers, spas, shower heads
No know human to human transmission |
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What is the clinical presentation of Legionella?
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Systemic infection with life-threatening pneumonia
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Who is at risk for severe Legionella pneumophila infections?
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Smokers, immunocompromied, elderly, male gender, COPD, DM
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What test has nearly 100% specificity for Legionella?
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Urine antigen test
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Name two zoonotic infections of the respiratory system.
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Chlamydia psicatti
Coxiella burnetti |
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Q Fever
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Zoonotic disease caused by Coxiella burnetti
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Ring granulomas in the bone marrow are suggestive of which disease?
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Q Fever
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What are the rare bacterial causes of CAP?
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Bacillus anthracis
Actionomyces israeli Nocardia asteroides Brucella species Francisella tularensis Yersinia pestis |
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What are the characteristics of Bacillus anthracis?
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Gram positive rod, large, spore-forming, non-motile, aerobic
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What is the mechanism for Bacillus anthracis toxin?
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Protective antigen (PA) binds to cell surface, transports edema factor (EF) and lethal factor (LF) to cytosol.
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What is the function of edema factor (EF) in Bacillus anthracis infection?
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Increases cAMP, causing water efflux from cells, leading to edema
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What is the function of lethal factor (LF) in Bacillus anthracis infection?
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Cleaves MAPKKK, leading to cell death
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What are the characteristic features of Actinomyces israeli?
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Gram positive rods (filamentous)
Anaerobic "Sulfur granules" |
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Nocardia asteroides
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Gram positive rods, partially acid fast
AEROBIC Red-orange colonies Lobar infiltrate |
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What are the risk factors for aspiration pneumonia?
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Alcohol / drugs
Stroke Anesthesia Loss of consciousness GERD Neurologic disease Dysphagia ET intubation / nasogastric tube |
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What is the most common cause of aspiration pneumonia in an intubated patient?
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Pseudomonas
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What are the characteristics of Streptococcus agalactiae?
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Gram positive, Group B, β-hemolytic
Resistant to bacitracin |
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What are the characteristic features of Mycobacterium tuberculosis
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Acid-fast rods, slender, slightly curved
Mycolic acid in cell wall |
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What are the risk factors for TB?
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Young, elderly, debilitated, alcoholics, homeless, HIV+
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What is the most common bacteria isolated from AIDS patients?
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Mycobacterium avium/intracellulare complex
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What causes swimming pool granuloma?
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Mycobacterium marinum
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Fungi usually grow as hyphae in the body or lab at higher temperatures.
True or False? |
False
They grow as single cell yeast |
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Name 3 pathogenic fungi
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Histoplasma
Blastomyces Coccidioides |
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Name 3 opportunistic fungi
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Candida
Aspergillus Pneumocystitis |
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Who is at risk for Histoplasmosis?
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Spelunkers, chicken farmers, or those exposed to bird and bat feces
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What fungi is common to the central United states, including the Ohio, Mississippi, and Missouri river valleys?
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Histoplasma
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Which fungi is a common cause of solitary pulmonary nodules or "coin lesions"?
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Histoplasma
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Microconidia?
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Histoplasma
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Which fungi is common in northwest Wisconsin and northeast Minnesota?
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Blastomycosis
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How can one differentiate between Blastomycosis and Histoplasma granulomas?
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Histoplasma granulomas are known to have cavitation/calcification
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What is the most common fungal infection in the desert southwest?
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Coccidiomycosis
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