GIM Question 22 Instructor

A 55 year-old woman is admitted from home with pneumonia.

  1. What are the most likely pathogens in this case?
    This woman is presenting with community-acquired pneumonia, of which the most common pathogens are Streptococcus pneumonia, Mycoplasma pneumonia, Chlamydophila pneumonia, and Hemophilus influenza. Respiratory viruses are also a major cause of pneumonia.
  2. What empiric antibiotic therapy would you treat her with?
    Empiric therapy to cover these pathogens in a patient admitted to hospital (or outpatients with comorbidities) includes:

      • Macrolide + 3rd generation cephalosporin
        • Azithromycin 500mg PO/IV q24h + ceftriaxone 1g IV q24h
      • Respiratory floroquinalone
        • Levofloxacin 750mg PO/IV q24h

    Empiric therapy with a macrolide or doxycycline alone can be used in outpatients with no comorbidities or prior antibiotic use.

  3. How would your management change if this woman was HIV+ with evidence of Pneumocystis jirovecii pneumonia (PJP)?
    • TMP-SMX (septra) 15-20mg/kg PO/IV q6-8hr daily for 21d
    • Dapsone with trimethoprim can be used as an alternative therapy

    In cases of PJP in HIV+ patients, acute management involves a 21 day course of septra or dapsone + trimethoprim as an alternative (NB: The patient may get worse initially despite therapy).

    • Septra 15 or 20mg/kg/day, divided into 3 or 4 doses

    Prophylactic therapy should follow:

    • Septra 2 tab (or one double strength tablet) PO daily
    • Maintain therapy until CD4 count > 200cells/mm3

    Prophylactic therapy should also be initiated once CD4 count <200cells/mm3 or a history of oral thrush.


  1. American Thoracic Society and Infectious Disease Society of America. Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia. Am J Respir Crit Care Med. 2005, 171:388-416.
  2. Mandell LA et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis. 2007, 44 Suppl 2:S27-72.
  3. Panel on Opportunistic Infections in HIV-Infected Adults and Adolescents. Guidelines for the prevention and treatment of opportunistic infections in HIV-infected adults and adolescents: recommendations from the Centre for Disease Control and Prevention, the National Institutes of Health, and the HIV Medicine Associaton of the Infectious Disease Society of America. 2009 Apr 10;58(RR-4):1-207; quiz CE1-4. Available at

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