Community Acquired Pneumonia
Signs and Symptoms
Cough (+/- sputum production), dyspnea, fever (+/- rigors), increased respiratory rate, altered breath sounds, altered chest X-ray, imparied oxygenation, incrased WBC count with left shift, chest pain
Subjective signs and symptoms and blood/sputum cultures
Epidemiological Conditions Related to Specific Pathogens
Condition Likely Pathogen(s)
Alcoholism Steptococcus pneumoniae, anaerobes
COPD and/or smoker S. pneumoniae, H. influenzae, Moraxella catarrhalis, Legionella species
Nursing home residency S. pneumoniae, gram-negative bacilli, H. influenzae, Staph. aureus, anaerobes, Chlamydia pneumoniae
Poor dental hygiene Anaerobes
Exposure to bats or bird droppings Histoplasma capsulatum
Esposure to birds Chlamydia psittaci
Exposure to rabbits Francisella tularensis
Early stage HIV infection S. pneumoniae, H. influenzae, Mycobacterium tuberculosis
Late stage HIV infection S. pneumoniae, H. influenzae, Mycobacterium tuberculosis, P. carinii, Cryptococcus, Histoplasma
Structural disease of lung Pseudomonas aeruginosa, Burkholderia cepacia, S. aureus
Intravenous drug abuse S. aureus, Anaerobes, M. tuberculosis, S. pneumoniae
Airway obstruction Anaerobes, S. pneumoniae, H. influenzae, S. aureus
Empiric Therapy
Outpatient therapy (young, otherwise healthy adult patients (< 60 years old))
  1. Doxycycline 100mg bid for 7-14 days  
  2. Clarithromycin or Azithromycin for 7-14 days  
  3. Select Fluoroquinolones (ex. Cipro or Levaquin)  
Moderately ill patients
  1. Parenteral beta-lactam agent (ex. Ceftriaxone or cefotaxime) plus macrolide (ex. Azithromycin)  
  2. Beta-lactam/beta-lactamase inhibitor (ex. Zosyn) plus macrolide (ex. Azithromycin)  
  3. Fluoroquinolone monotherapy (ex. Cipro or Levaquin)  
Severely ill (ICU patient)
  1. Parenteral macrolide (ex. Azithromycin) or fluoroquinolone (ex. Levaquin) plus ceftriaxone, cefotaxime - preferred  
  2. Beta lactam/beta-lactamase inhibitor (ex. Zosyn)  
Structural lung disease
  Antipseudomonal agent (ex. Imipenem, Gentamicin) plus fluoroquinolone  
Suspected aspiration
  Augmentin, clindamycin, ceftazidime, amikacin, or vancomycin  
Treatment Guidelines Based on Cultures
Streptococcus pneumonia (penicillin susceptible)
  Preferred therapy: Penicillin-V (oral) or Penicillin-G (parenteral), amoxicillin, or ampicillin  
  Secondary therapies (penicillin allergy, etc.): Erythromycin, clarithromycin, azithromycin, tetracycline, doxycycline, gatifloxacin, moxefloxacin, clindamycin, levofloxacin, ceftriaxone, cefuroxime  
Streptococcus pneumonia (intermediate penicillin resistant strains)
  Preferred therapy: Penicillin-G, ampicillin, amoxicillin, ceftriaxone, cefotaxime, second generation fluoroquinolone (levofloxacin)  
  Alternative therapy: Clindamycin or doxycycline  
Steptococcus pneumonia (high penicillin resistant strains)
  Preferred therapy: Vancomycin (as per renal function), gram-positive fluoroquinolones (ex. Levofloxacin)  
  Alternative therapy: Linezolid or Synercid  
Haemophilus influenzae (beta-lactamase negative)
  Preferred therapy: Ampicillin or amoxicillin  
  Alternative therapy: Cephalosporins, doxycycline, fluoroquinolones  
Haemophilus influenzae (beta-lactamase positive)
  Preferred therapy: Mixed or gram negative cephalosporins (ex. Cefotaxime or ceftriaxone), beta-lactamase inhibitor agents (ex. Zosyn), fluoroquinolones, doxycycline  
  Alternative therapy: Co-trimoxazole, azithromycin, clarithromycin  
Mycoplasma pneumoniae
Atypical agent with persistant symptoms - may require up to 21 days of therapy
  Use macrolides, doxycycline, or fluoroquinolones  
Legionella pneumophilia
Water borne pathogen - high fever and GI symptoms are common
  Erythromycin 1g IV q6h +/- rifampin 600mg daily for 21 days  
1. Reduction in temperature
2. Reduction in white blood cell count
3. Resolution in left shift
4. Improvement in oxygenation
5. Improvement of associated signs/symptoms
6. Routine chest X-rays are not appropriate for patient monitoring
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