This document provides guidelines for treating various gram-positive and gram-negative bacteria, including recommendations for drugs of choice and alternative treatments. It lists bacteria such as Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and others. For each pathogen, it recommends first-line and alternative antibiotic therapies based on factors like infection severity and antibiotic resistance profile. The guidelines aim to help clinicians select optimal antibiotic treatment strategies for different bacterial infections.

1. Drugs of Choice, First Choice,
Alternative(s)
1. GRAM-POSITIVE COCCI
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2. 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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3. 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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4. 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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5. 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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6. 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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7. Streptococcus, viridans group:
• Penicillin G ± gentamicine
• Cefotaxime,c ceftriaxone,c erythromycin, azithromycin, clarithromycin, or
vancomycin ± gentamicin
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8. Drugs of Choice, First Choice,
Alternative(s)
2. GRAM-NEGATIVE COCCI
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9. 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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10. 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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11. 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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12. Drugs of Choice, First Choice,
Alternative(s)
4. GRAM-NEGATIVE BACILLI
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13. 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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14. 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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15. 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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16. 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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17. 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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18. 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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19. 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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20. 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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21. 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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