Table 9: Empiric Antimicrobial Therapy for Community-acquired Pneumonia In Immunocompetent Adults

Table 9:

Empiric Antimicrobial Therapy for Community-acquired
Pneumonia In Immunocompetent Adults

Patient/Setting	Common Pathogens	IDSA Empiric Therapy	ATS Empiric Therapy
Outpatient < 60 years old No comorbid diseases	S pneumoniae M pneumoniae C pneumoniae H influenzae Viruses	A macrolide or doxycycline	A macrolide or doxycycline
Outpatient > 65 years old or having comorbid disease or antibiotic therapy within last 3 months	S pneumoniae (drug-resistant) M pneumoniae C pneumoniae H influenzae Viruses Gram-negative bacilli^b S aureus^b	A macrolide, doxycycline, or a fluoroquinolone^a	A beta-lactam^f and (macrolide or doxycycline) or a fluoroquinolone^a alone
Inpatient Not severely ill	S pneumoniae H influenzae Polymicrobial Anaerobes S aureus C pneumoniae Viruses	A macrolide and cefotaxime or ceftriaxone or a beta-lactam/beta lactamase inhibitor^e; a fluoroquinolone^calone	Cardiopulmonary disease or risk factors: IV beta-lactam^g and (IV or oral macrolide or doxycycline) or IV antipneumococcal fluoroquinolone^aalone No cardiopulmonary disease or risk factors: intravenous azithromycin alone. If macrolide allergic: doxycycline and a beta-lactam^g or an antipneumococcal fluoroquinolone alone.
Inpatient Severely ill	S pneumoniae^d Legionella Gram-negative bacilli M pneumoniae Viruses S aureus	Erythromycin, azithromycin, or a fluoroquinolone^c and cefotaxime, ceftriaxone, or a beta lactam/beta lactamase inhibitor^e	P aeruginosa unlikely: IV beta-lactam and (IV macrolide or fluoroquinolone). P aeruginosa possible: (IV macrolide or fluoroquinolone and aminoglycoside IV) or (antipseudomonal quinolone) and antipseudomonal beta-lactam

In the outpatient setting, many authorities prefer to reserve fluoroquinolones
(Levofloxacin, gatifloxacin, moxifloxacin, gemifloxacin) for patients with comorbid diseases/risk factors

In most cases, patients with pneumonias due to these organisms should be hospitalized

Levofloxacin, gatifloxacin, moxifloxacin, or gemifloxacin

Critically ill patients in areas with significant rates of high-level pneumococcal resistance and a suggestive sputum gram-stain should receive vancomycin or a newer quinolone pending microbiologic diagnosis.

Piperacillin-tazobactam or ampicillin-sulbactam

Cefpodoxime, cefuroxime, high-dose amoxicillin, amoxicillin/clavulanate; or parenteral ceftriaxone followed by oral cefpodoxime

Cefotaxime, ceftriaxone, ampicillin/sulbactam, or high-dose ampicillin.

Table modified from references 2 and 5

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