Is any antibiotic suitable for treatment?

Antibiotic Selection Guidelines for Various Infections

The appropriate antibiotic selection depends on the specific infection being treated, with first-line and alternative options clearly defined by evidence-based guidelines for each condition. 1

General Principles of Antibiotic Selection

• Antibiotics should be selected based on the site of infection, suspected pathogens, local resistance patterns, and patient characteristics 2
• Obtain appropriate microbiological samples before starting antibiotics whenever possible to guide targeted therapy 2
• Consider de-escalation of broad-spectrum therapy once culture results are available 2
• Prescribe antibiotics at optimal dosing and appropriate duration for each specific clinical situation 2

Infection-Specific Antibiotic Recommendations

Skin and Soft Tissue Infections

• Mild infections: First-line options include amoxicillin-clavulanic acid, cloxacillin, or cefalexin 1
• Necrotizing fasciitis: Combination therapy with clindamycin plus piperacillin-tazobactam (with or without vancomycin), or ceftriaxone plus metronidazole (with or without vancomycin) 1
• Animal bites: Amoxicillin-clavulanic acid for oral treatment; ampicillin-sulbactam, piperacillin-tazobactam, or second/third-generation cephalosporins for intravenous treatment 1
• Human bites: Amoxicillin-clavulanic acid or ampicillin-sulbactam; carbapenems and doxycycline as alternatives 1
• Diabetic wound infections:
  • Mild: Dicloxacillin, clindamycin, cefalexin, levofloxacin, amoxicillin-clavulanic acid, or doxycycline 1
  • Moderate to severe: Levofloxacin, cefoxitin, ceftriaxone, ampicillin-sulbactam, moxifloxacin, ertapenem, tigecycline, or ciprofloxacin with clindamycin 1

Intra-abdominal Infections

• Mild to moderate: First-line options include amoxicillin-clavulanic acid or ampicillin plus gentamicin plus metronidazole; second-line options include ciprofloxacin plus metronidazole or cefotaxime/ceftriaxone plus metronidazole 1
• Severe: First-line options include cefotaxime/ceftriaxone plus metronidazole or piperacillin-tazobactam; second-line options include ampicillin plus gentamicin plus metronidazole or meropenem 1

Acute Infectious Diarrhea

• Antibiotics generally not recommended for uncomplicated cases 1
• For confirmed bacterial infections requiring treatment:
  • Shigella infections: Sulfamethoxazole-trimethoprim or ceftriaxone 1
  • Cholera: Azithromycin or doxycycline 1
  • C. difficile infections: Oral metronidazole or oral vancomycin 1

Respiratory Tract Infections

• Acute bronchitis: Antibiotics not recommended for otherwise healthy individuals 1
• Acute bronchiolitis: Antibiotics not routinely recommended unless there is strong suspicion of bacterial infection 1
• Community-acquired pneumonia (CAP):
  • Non-severe CAP: Oral amoxicillin or combination of amoxicillin with a macrolide 1
  • Severe CAP: Intravenous combination of a broad-spectrum β-lactamase stable antibiotic (co-amoxiclav, cefuroxime, cefotaxime, or ceftriaxone) with a macrolide 1
  • Pediatric CAP: Amoxicillin for children under 3 years; macrolides for children over 3 years if atypical pathogens are suspected 1

Sinusitis

• Maxillary sinusitis: Amoxicillin-clavulanate, second/third-generation cephalosporins (cefuroxime-axetil, cefpodoxime-proxetil), or pristinamycin 1
• Frontal, ethmoidal, or sphenoidal sinusitis: Same as maxillary sinusitis, or fluoroquinolones active against pneumococci (levofloxacin, moxifloxacin) 1

Special Considerations

Anthrax Exposure

• Adults: Ciprofloxacin 500 mg orally twice daily or doxycycline 100 mg orally twice daily for 60 days 1
• Children: Ciprofloxacin 10-15 mg/kg every 12 hours (not exceeding 1 g/day) or age-appropriate doxycycline dosing for 60 days 1

Multidrug-Resistant Gram-Negative Bacteria

• Consider patient colonization status and local resistance patterns when selecting perioperative antibiotic prophylaxis 1
• For extended-spectrum cephalosporin-resistant Enterobacterales:
  • Non-severe infections: Aminoglycosides, trimethoprim-sulfamethoxazole, or fosfomycin 1
  • Severe infections: Carbapenems (preferably ertapenem for bloodstream infections without septic shock) 1

Common Pitfalls to Avoid

• Using antibiotics to treat fever without identifying a bacterial source of infection 2
• Continuing unnecessarily broad-spectrum antibiotics when narrower options are available 2, 3
• Failing to adjust antibiotic therapy based on culture results 2
• Prescribing antibiotics for viral infections or non-infectious conditions 4
• Not considering local resistance patterns when selecting empiric therapy 3
• Inappropriate antibiotic duration leading to resistance development or treatment failure 3

Antibiotic Stewardship Principles

• Collaborate with infectious disease specialists, clinical microbiologists, and pharmacists when making antibiotic decisions 2, 5
• Implement rapid diagnostic testing when available to guide appropriate antibiotic selection 3
• Consider pharmacokinetic optimization and therapeutic drug monitoring, especially in critically ill patients 3
• Recognize that inappropriate antibiotic use contributes to resistance and disrupts the human microbiota 6