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Organism |
Preferred antimicrobials |
Alternative antimicrobials |
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Streptococcus pneumoniae |
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Penicillin nonresistant; MIC <2 microg/mL |
Penicillin G, amoxicillin |
Macrolide, cephalosporins (oral [cefpodoxime, cefprozil, cefuroxime, cefdinir, cefditoren] or parenteral [cefuroxime, ceftriaxone, cefotaxime]), clindamycin, doxycycline, respiratory fluoroquinolonea |
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Penicillin resistant; MIC ≥2 microg/mL |
Agents chosen on the basis of susceptibility, including cefotaxime, ceftriaxone, fluoroquinolone |
Vancomycin, linezolid, high-dose amoxicillin (3 g/d with penicillin MIC ≤4 microg/mL) |
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Haemophilus influenzae |
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Non–beta-lactamase producing |
Amoxicillin |
Fluoroquinolone, doxycycline, azithromycin, clarithromycinb |
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Beta-lactamase producing |
Second- or third-generation cephalosporin, amoxicillin/clavulanate |
Fluoroquinolone, doxycycline, azithromycin, clarithromycinb |
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Mycoplasma pneumoniae/Chlamydophila pneumoniae |
Macrolide, a tetracycline |
Fluoroquinolone |
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Legionella spp |
Fluoroquinolone, azithromycin |
Doxycycline |
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Chlamydophila psittaci |
A tetracycline |
Macrolide |
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Coxiella burnetii |
A tetracycline |
Macrolide |
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Francisella tularensis |
Doxycycline |
Gentamicin, streptomycin |
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Yersinia pestis |
Streptomycin, gentamicin |
Doxycycline, fluoroquinolone |
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Bacillus anthracis (inhalation) |
Ciprofloxacin, levofloxacin, doxycycline (usually with a second agent) |
Other fluoroquinolones; beta-lactam, if susceptible; rifampin; clindamycin; chloramphenicol |
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Enterobacteriaceae |
Third-generation cephalosporin, carbapenemc (drug of choice if extended-spectrum beta-lactamase producer) |
Beta-lactam/beta-lactamase inhibitor,d fluoroquinolone |
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Pseudomonas aeruginosa |
Antipseudomonal beta-lactame plus (ciprofloxacin or levofloxacinf or aminoglycoside) |
Aminoglycoside plus (ciprofloxacin or levofloxacinf) |
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Burkholderia pseudomallei |
Carbapenem, ceftazidime |
Fluoroquinolone, TMP/SMX |
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Acinetobacter spp |
Carbapenem |
Cephalosporin-aminoglycoside, ampicillin/sulbactam, colistin |
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Staphylococcus aureus |
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Methicillin susceptible |
Antistaphylococcal penicilling |
Cefazolin, clindamycin |
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Methicillin resistant |
Vancomycin or linezolid |
TMP/SMX |
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Bordetella pertussis |
Macrolide |
TMP/SMX |
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Anaerobe (aspiration) |
Beta-lactam/beta-lactamase inhibitor,d clindamycin |
Carbapenem |
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Influenza virus |
Oseltamivir or zanamivir |
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Mycobacterium tuberculosis |
Isoniazid plus rifampin plus ethambutol plus pyrazinamide |
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Coccidioides spp |
For uncomplicated infection in a normal host, no therapy generally recommended; for therapy, itraconazole, fluconazole |
Amphotericin B |
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Histoplasmosis |
Itraconazole |
Amphotericin B |
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Blastomycosis |
Itraconazole |
Amphotericin B |
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Choices should be modified on the basis of susceptibility test results and advice from local specialists. Refer to local references for appropriate doses. |
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a Levofloxacin, moxifloxacin, gemifloxacin (not a first-line choice for penicillin susceptible strains); ciprofloxacin is appropriate for Legionella and most gram-negative bacilli (including Haemophilus influenzae). b Azithromycin is more active in vitro than clarithromycin for H influenzae. c Imipenem/cilastatin, meropenem, ertapenem. d Piperacillin/tazobactam for gram-negative bacilli, ticarcillin/clavulanate, ampicillin/sulbactam, or amoxicillin/clavulanate. e Ticarcillin, piperacillin, ceftazidime, cefepime, aztreonam, imipenem, meropenem. f 750 mg daily. g Nafcillin, oxacillin, flucloxacillin. |
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INN, international nonproprietary name; MIC, minimum inhibitory concentration; trimethoprim/sulfamethoxazole. |
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