• Community-acquired bacterial pneumonia: Streptococcus pneumoniae, (Pneumococcus) Gram stain, sputum
  • Most frequent cause: Streptococcus pneumoniae (pneumococci)
    • Chest X-RAY
    • > 30% of recent S. pneumoniae isolates:
      • relatively or highly resistant to penicillin and sometimes cephalosporins.
  •  Other pathogens:
    •  Haemophilus influenzae
    •  Staphylococcus aureus
    •  Klebsiella pneumoniae
    •  occasionally: other gram-negative bacilli and anaerobic mouth organisms
    • "Atypical" pathogens:
      • Legionella
      • Mycoplasma pneumoniae
      • Chlamydia pneumoniae
      • respiratory viruses
      • tuberculosis
      • Pneumocystis carinii

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• Diagnosis
• Treatment: In Hospitalized Patients--
  • Pending culture results and susceptibility testing:
    •  Reasonable first-choice: cefotaxime or ceftriaxone
      •  Cefotaxime (Claforan), ceftriaxone (Rocephin), high-doses of penicillin (IV) effective in treating pneumococcal pneumonia (intermediate resistance)
    •   Vancomycin (Vancocin): high resistance
    •  Vancomycin (Vancocin) and cephalosporin: severe illness-- not responding to a beta-lactam.
    • A macrolide (erythromycin, azithromycin (Zythromax), or clarithromycin (Biaxin)) added to a fluoroquinone (good activity against S. pneumoniae --  levofloxacin (Levaquin), grepafloxacin and trovafloxacin) can be used to cover Legionella, Mycoplasma, chlamydia.
      • If aspiration pneumonia is a concern: clindamycin (Cleocin) or metronidazole (Flagyl) may be added.

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• Treatment for Ambulatory Patients:
  • Treatment Recommended for otherwise healthy patients with pneumonia due to Mycoplasma or Chlamydia:
    • Oral macrolide ( erythromycin,  azithromycin (Zythromax), or  clarithromycin (Biaxin)),  doxycycline (Vibramycin, Doryx), or fluoroquinones with good anti-pneumococcal activity (levofloxacin (Levaquin), grepafloxacin, trovafloxacin)
    •  Penicillin-resistant pneumococci: may be resistant to a macrolide or doxycycline
    • Older patients or patients with underlying disease: recommendation --
      •  levofloxacin (Levaquin)
      •  grepafloxacin
      •  trovafloxacin

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• Treatment for hospital-acquired bacterial pneumonia:
  • Most often cause by gram-negative bacilli:
    • Klebsiella
    • Enterobacter
    • Serratia
    • Acinetobacter AND
  • Pseudomonas aeruginosa
  • Staphylococcus aureus
  • The initial treatment: third-generation cephalosporin --
    •  cefotaxime (Claforan)
    •  ceftizoxime (Cefizox)
    •  ceftriaxone (Rocephin)
    •  ceftazidime (Fortax, Taxidime, Tazicef)
  • Or:
    •  cefepime (Maxipime)
    •  ticarcillin (Ticar)/ clavulanic acid
    •  piperacillin (Pipracil)/tazobactam
    •  meropenem (Merrem IV)
    •  imipenem
  • with or without the aminoglycoside {tobramycin (Nebcin), gentamicin (Garamycin), or amikacin (Amikin)}
  •  Considering third-generation cephalosporins:
    • Cefotaxime (Claforan), ceftizoxime (Cefizox), and ceftriaxone (Rocephin)} limited activity against Pseudomonas
    • Ceftazidime (Fortax, Taxidime, Tazicef)} more activity against staphylococci and other gram-positive cocci
  • In the intensive care unit -- nosocomial pneumonia due to highly resistant gram-negative bacteria and Pseudomonas aeruginosa:
    • Good first choices--
      • imipenem
      • meropenem (Merrem IV)
      • plus aminoglycoside
      • add vancomycin (Vancocin) in hospitals where methicillin (Staphcillin)-resistant staphylococci are common.

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