Bacterial Pneumonias Flashcards
What are the 4 most important signs of “typical” pnemonia?
- Acute onset
- Productive cough
- Lung consolidation (with chest x-ray)
- No extra-pulmonary symptoms
What are the 3 most important signs of “atypical” pneumonia?
- Slow onset
- Non-productive cough
- Frequent extra-pulmonary symptoms
What are the 3 most common causes of “typical” pneumonia if it is community aquired?
- Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
What are the 3 most common causes of “atypical” pneumonia if it is community aquired?
- Legionella sp.
- Mycoplasma pneumoniae
- Chlamydophila pneumoniae
What is the definition of hospital aquired pnemonia?
Pneumonia occuring in a patient 7 days after hospitalization.
What cause of pneumonia will can you especially see in alcoholics and COPD patients?
Klebsiella (these patients are immune compromised)
(Furthermore… Although it’s rarely seen in Community Aquired Pneumonia, it is a cause of healthcare associated, hospital aquired pneumonias, and ventilator associated pneumonias.)
What sources of pneumonia will you especially see in cystic fibrosis patients?
- Pseudomonas aeruginosa (they love wet environments)
- Berkholderia
What the hell is this?
- Gram positive
- Diplococci
- Streptoccocus pneumoniae
What is the empiric therapy for an in-patient with CAP?
- Advanced macrolide (clarithromycin, azithromycin, etc… (anything except erythromycin)) + b-lactam (penicillin, ampicillin, carbapenem, etc.)
or. .. - Repiratory floroquinolone (moxifloxacin, gemifloxacin, levofloxacin)
What is the empiric therapy for an outpatient with CAP?
- Macrolide (clarithromycin, azithromycin, erythromycin, etc.)
or
- doxycycline (unless you are pregnant)
What is the emperic therapy for a patient with CAP who already had recent antibiotic treatment?
- Advanced macrolide (clarithromycin, azithromycin, etc… (anything except erythromycin)) + amoxicillin +/- clavulanate
or. .. - Repiratory floroquinolone (moxifloxacin, gemifloxacin, levofloxacin)
What are 4 culture results for Steptococcus pneumoniae?
- Growth on blood agar
- Alpha hemolytic (brown, muddy)
- Optocin disc sensitive
- Positive bile solubility test (bile turns clear becayse it has lysed the Step. pneumo
What are the 2 mechanisms for Steptoccocus pneumoniae resistance and how is Pneumococci treated?
- Altered Penicillin Binding Protein (aka transpeptidase) = penicillin resistance
- Efflux pumps = resistance to macrolides, TMP/SMX, and fluroquinolones
- Penicillin, amoxicillin, ampicillin treatment for sensitive Pneumococci
- Respiratory floroquinolone treatment for restsitant strains
Describe the histologic features of Haemophilus influenzae and it’s 2 main virulence factor.
- Gram negative
- pleomorphic rod (it can change its shape)
- H. influenzae serotype b produces an anti-phagocytic capsule
- Both typable and non-typable strains produce beta-lactamase… so this means you need to treat it with Amoxicillin-clavulanate
Discribe the histological features of Moraxella catarrhalis.
- Gram neagtive
- Diplococci
- Aerobic
- Oxidase-positive
- Non-hemolytic on blood agar
What are the 2 most common causes of post-influenza pnuemonia?
- Steptococcus pneumoniae
- Staphylococcus aureus
What bacteria is associated with necrotizing pneumonia?
Staphylococcus aureus (especially MRSA)
What are some histological features of Staphylococcus aureus?
- Gram positive
- Cocci
- Beta-hemolytic (yellow color on blood agar)
- Catalase positive
- Coagulase positive
- Oxacillin resistant (MRSA)
What does Legionella grow on, what symptoms does it cause, and how is it treated?
- BCYE agar (charcol = black)
- It does not gram stain (facultative intracellular pathogen)
- Fever, chills, non-productive cough, headache; affects the GI tract, liver, kidneys, etc.
- Affects immunocompromised patients
- Azithromycin or Levofloxacin
What are the 2 causes of “walking pneumonia”?
- Mycoplasma pneumoniae
- Chlamydophila/chlamydia
What is the pathogenesis of Mycoplasma pneumonia, does it show up on gram stain, and how is it treated?
- P1 adhesion protein mediates attachment to cilia. Cilia stop moving and epithelial cells die.
- It does not gram stain. (Fried-egg appearence in culture)
- Macrolides or respiratory fluoroquinolone
What makes Chlamydophila so weird and how is it treated?
- It’s an obligate intracellular pathogen
- It exists as elementary (infective form) and reticulate bodies
- It does not gram stain
- Doxycycline (except for pregnant women and children) or macrolide
What are the 3 most common causes of Hospital Aquired Pneumonia?
- Pseudomonas aeruginosa
- Klebsiella pneumoniae
- MSSA/MRSA
What is the emperic therapy for Hospital Aquired Pneumonia?
- 4th generation cephalosporin or carbapenem or extended spectrum penicilin + beta-lactamase inhibitor
- fluroquinolone or aminoglycoside
- If MRSA is suspected, add vancoymcin or linezolid
