export_bacterial lrt infections i Flashcards
Pneumonia
Inflammation of the lung parenchyma with fluid accumulation in the alveoli, which blocks effective gas exchange
Features of pneumonia
Fever
Malaise
Cough/sputum
Pleuritic chest pain
Dyspnea
Crackles/rales
Common bacteria that cause lobar pneumonia
Strep. pneumoniae
Staph. aureus
H. influenzae
Most Gram-negative bacteria
Common bacteria that cause atypical pneumonia
Mycoplasma pneumoniae
Chlamydophila pneumoniae
Legionella pneumophila
Typical pneumonia features
Sudden onset
Toxic facies
Productive cough (purulent or bloody sputum)
Frequent pleurisy and consolidation
Left-shift, elevated WBCs
Lobar, dense CXR
Atypical pneumonia features
Gradual onset
Well facies
Nonproductive cough (scant, watery sputum)
Rarely have pleurisy or consolidation
Normal WBCs
Patchy CXR
Bronchiectasis
Localized, permanent dilation of the bronchi and bronchioles, caused by muscle and elastic tissue damage
Complication of pneumonia
Aspiration pneumonia cause
Introduction of foreign material into bronchial tree, such as aspiration of vomit in alcoholics
Hospital acquired pneumonia
Nosocomial
Immunocompromised, associated with ventilator use
Most frequent cause of HAP
MDR Gram-negatives
Sputum analysis to diagnose pneumonia
> 25 PMNs and <10 epithelial cells per 100x field
Strep. pneumoiae is also called?
Pneumococcus
Pneumococcus virulence factors
Surface adhesins
IgA protease
Pneumolysin
Teichoic acid and peptidoglycan
Polysaccharide capsule
Pneumolysin
Pore forming toxin, colonization, invasion, inflammation, and complement activation, etc.
Pneumococcal pneumonia presentation
Rust-colored sputum
Preceded by rhinorrhea
Severe, pleuritic chest pain
Two diagnostic laboratory tests for pneumococcal pneumonia
Bile solubility positive
Optochin sensitive
Treatment for pneumococcal pneumonia
Empiric - penicillin, macrolide-azithromycin, or cephalosporin
Diagnostic feature of Staph. aureus
Coagulase positive
Virulence factors of Staph. aureus
Coagulase
Protein A
Panton-Valentine leukocidin (pore-forming cytotoxin)
MRSA characteristics
Staph. aureus that is methicillin resistant
Resistant to all beta-lactam antibiotics
Not necessarily more virulent, just harder to treat
MRSA treatments
Penicillins/cephalosporins if not resistant
Otherwise, linezolid or vancomycin
Gram-negative facultative anaerobe that causes pneumonia
Klesiella pneumoniae
Gram-negative aerobe that causes pneumonia
Pseudomonas aeruginosa
Gram-negative pneumonia treatment
Multiple drug therapy
Prevent emergent antibiotic-resistant strains
Drug synergism
IV drug cocktail
Klebsiella pneumoniae characteristics
Gram-negative rod
Non-motile
Mucoid colonies
Beta-lactamases
Oxidase negative
Virulence factors of Klebsiella pneumoniae
LPS
Capsule
Klebsiella pneumoniae treatment
Same as other Gram-negative pneumonias
Increasing rate of antibiotic resistance
Pseudomonas aeruginosa
Gram-negative rod
Flagellated
Obligate aerobe (sugar fermentation negative)
Oxidase positive
Virulence factors of pseudomonas aeruginosa
Toxin A
Leukocidin
Phospholipase C
Capsule
Pyocyanin
Pyoverdin
Treatment of pseudomonas aeruginosa
Antipseudomonal penicillins
plus an aminoglycoside
What other disease does pseudomonas aeruginosa cause particular problems for?
Cystic fibrosis
