Drugs of Choice, First Choice,
Alternative(s)
1. GRAM-POSITIVE COCCI
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3/22/2023

Enterococcus faecalis (generally not as resistant to
antibiotics as Enterococcus faecium):
• Serious infection (endocarditis, meningitis, pyelonephritis
with bacteremia)
– Ampicillin (or penicillin G) + (gentamicin or streptomycin)
– Vancomycin + (gentamicin or streptomycin), daptomycin, linezolid,
– tedizolid, telavancin, tigecyclinea
• Urinary tract infection
– Ampicillin, amoxicillin
– Fosfomycin or nitrofurantoin
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E. faecium (generally more resistant to antibiotics than
E. faecalis):
• Recommend consultation with infectious disease specialist
– Linezolid,
– quinupristin/dalfopristin,
– daptomycin,
– tigecycline
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Staphylococcus aureus/Staphylococcus epidermidis:
• Methicillin (oxacillin)-sensitive
– Nafcillin or oxacillin
– FGC,b,c trimethoprim–sulfamethoxazole, clindamycin, BL/BLId
• Hospital-acquired methicillin (oxacillin)–resistant
– Vancomycin ± (gentamicin or rifampin)
– Ceftaroline, daptomycin, linezolid, telavancin, tigecycline, atrimethoprim–
sulfamethoxazole, quinupristin–dalfopristin
• Community-acquired methicillin (oxacillin)–resistant
– Clindamycin, trimethoprim–sulfamethoxazole, doxycyclinea
– Ceftaroline, dalbavancin, daptomycin, linezolid, oritivancin, tedizolid, telavancin,
tigecycline,a or vancomycin
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Streptococcus (groups A, B, C, G, and Streptococcus
bovis):
• Penicillin G or V or ampicillin
• FGC,b,c erythromycin, azithromycin, clarithromycin
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Streptococcus pneumonia:
• Penicillin-sensitive (minimal inhibitory concentration [MIC] <0.1 mcg/mL
[mg/L])
– Penicillin G or V or ampicillin
– FGC,b,c doxycycline,a azithromycin, clarithromycin, erythromycin
• Penicillin intermediate (MIC 0.1-1 mcg/mL [mg/L])
– High-dose penicillin (12 million units/day for adults) or ceftriaxonec or
cefotaximec
– Levofloxacin,a moxifloxacin,a gemifloxacin,a or vancomycin
• Penicillin-resistant (MIC ≥1.0 mcg/mL [mg/L])
– Recommend consultation with infectious disease specialist.
• Vancomycin ± rifampin
• Per sensitivities: ceftaroline, cefotaxime, ceftriaxone,c levofloxacin,a moxifloxacin,a or
gemifloxacina
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Streptococcus, viridans group:
• Penicillin G ± gentamicine
• Cefotaxime,c ceftriaxone,c erythromycin, azithromycin, clarithromycin, or
vancomycin ± gentamicin
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Drugs of Choice, First Choice,
Alternative(s)
2. GRAM-NEGATIVE COCCI
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3/22/2023

Moraxella (Branhamella) catarrhalis:
• Amoxicillin–clavulanate, ampicillin–sulbactam
• Trimethoprim–sulfamethoxazole, erythromycin, azithromycin,
clarithromycin, doxycycline,a SGC,c, f cefotaxime,c ceftriaxone,c or
TGCPOc,g
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Neisseria gonorrhoeae (also give concomitant treatment
for Chlamydia trachomatis):
• Disseminated gonococcal infection
– Ceftriaxonec or cefotaximec
– Oral follow-up: cefpodoxime,c ciprofloxacin,a or levofloxacina
• Uncomplicated infection
– Ceftriaxone,c cefotaxime,c or cefpodoximec
– Ciprofloxacina or levofloxacina
Neisseria meningitides:
• Penicillin G
• Cefotaximec or ceftriaxonec
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3. GRAM-POSITIVE BACILLI
• Clostridium perfringens
– Penicillin G ± clindamycin
– Metronidazole,a clindamycin, doxycycline,a cefazolin,c carbapenemh,i
• Clostridioides (formerly Clostridium) difficile
– oral vancomycin or fidaxomicin
– oral metronidazole
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Drugs of Choice, First Choice,
Alternative(s)
4. GRAM-NEGATIVE BACILLI
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3/22/2023

Acinetobacter spp.:
– Doripenem, imipenem, or meropenem ± aminoglycosidej (amikacin usually most
effective)
– Ampicillin–sulbactam, polymyxins,i or tigecyclinea
• Bacteroides fragilis (and others):
– Metronidazolea
– BL/BLI,d clindamycin, cefoxitin,c cefotetan,c ceftolozane-azobactam, ceftazidime-
avibactam, or carbapenemh,i
Enterobacter spp.:
– Carbapenemh or cefepime ± aminoglycosidej
– Ceftolozane-tazobactam, ceftazidime-avibactam, ciprofloxacin,a levofloxacin,a
piperacillin–tazobactam, ticarcillin–clavulanate
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Escherichia coli:
• Meningitis
– Cefotaxime,c ceftriaxone,c meropenem
• Systemic infection
– Cefotaximec or ceftriaxonec
– BL/BLI,d fluoroquinolone,a,k carbapenemh,i
• Urinary tract infection
– Most oral agents: check sensitivities
– Ampicillin, amoxicillin–clavulanate, doxycycline,a or cephalexinc
– Aminoglycoside,j FGC,b,c nitrofurantoin, fluoroquinolonea,k
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Gardnerella vaginalis:
– Metronidazolea
– Clindamycin
Haemophilus influenza:
– Meningitis
• Cefotaximec or ceftriaxonec
• Meropenemi
– Other infections
– BL/BLI,d or if β-lactamase-negative, ampicillin or amoxicillin
• Trimethoprim–sulfamethoxazole, cefuroxime,c azithromycin, clarithromycin, or
fluoroquinolonea,k
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Klebsiella pneumonia:
– BL/BLI,d cefotaxime,c ceftriaxone,c cefepimec
– Carbapenem,h,i ceftolozane-tazobactam, ceftazidime-avibactam, fluoroquinolonea,k
Legionella spp.:
– Azithromycin, erythromycin ± rifampin, or fluoroquinolonea,k
– Trimethoprim–sulfamethoxazole, clarithromycin, or doxycyclinea
Pasteurella multocida:
– Penicillin G, ampicillin, amoxicillin
– Doxycycline,a BL/BLI,d trimethoprim–sulfamethoxazole or ceftriaxonec
Proteus mirabilis:
– Ampicillin
– Trimethoprim–sulfamethoxazole
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Proteus (indole-positive) (including Providencia rettgeri,
Morganella morganii, and Proteus vulgaris):
• Cefotaxime,c ceftriaxone,c or fluoroquinolonea,k
• BL/BLI,d aztreonam,l aminoglycosides,j carbapenem,h,i
ceftolozanetazobactam, ceftazidime-avibactam
Providencia stuartii:
• Amikacin, cefotaxime,c ceftriaxone,c fluoroquinolonea,k
• Trimethoprim–sulfamethoxazole, aztreonam,l carbapenemh,i
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Pseudomonas aeruginosa:
• Urinary tract infection only
– Aminoglycosidej
– Ciprofloxacin,a levofloxacina
• Systemic infection
– Cefepime,c ceftazidime,c doripenem,i imipenem,i meropenem,I piperacillin–
tazobactam, or ticarcillin–clavulanate + aminoglycosidej
– Aztreonam,l ceftolozane-tazobactam, ceftazidime-avibactam, ciprofloxacin,a
levofloxacin, a polymyxini
Salmonella typhi:
– Ciprofloxacin,a levofloxacin,c ceftriaxone,c cefotaximec
– Trimethoprim–sulfamethoxazole
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Serratia marcescens:
– Ceftriaxone,c cefotaxime,c cefepime,c ciprofloxacin,a levofloxacina
– Aztreonam, l carbapenem, h,i piperacillin–tazobactam, ticarcillin–clavulanate
• Stenotrophomonas (Xanthomonas) maltophilia (generally very
resistant to all antimicrobials):
– Trimethoprim–sulfamethoxazole.
– Check sensitivities to ceftazidime,c doxycycline,a minocycline,a and ticarcillin–
clavulanate.
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5. MISCELLANEOUS MICROORGANISMS
Chlamydia pneumoniae:
• Doxycyclinea
• Azithromycin, clarithromycin, erythromycin, or fluoroquinolonea,k
C. trachomatis:
• Azithromycin or doxycyclinea
• Levofloxacin,a erythromycin
Mycoplasma pneumoniae:
• Azithromycin, clarithromycin, erythromycin, fluoroquinolonea,k
• Doxycyclinea
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6. SPIROCHETES
Treponema pallidum:
• Neurosyphilis
– Penicillin G
– Ceftriaxonec
• Primary or secondary
– Benzathine, penicillin G
– Ceftriaxonec or doxycyclinea
Borrelia burgdorferi (choice depends on stage of disease):
• Ceftriaxonec or cefuroxime axetil,c doxycycline,a amoxicillin
• High-dose penicillin, cefotaximec
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