What infections is vancomycin used to treat?

What Vancomycin Treats

Vancomycin is primarily used to treat serious infections caused by Gram-positive bacteria, particularly methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant coagulase-negative staphylococci, and severe Clostridioides difficile infection (CDI).

Primary Indications

Intravenous Vancomycin

Serious beta-lactam-resistant Gram-positive infections are the core indication for IV vancomycin 1, 2. The FDA-approved uses include:

• Methicillin-resistant staphylococcal infections (MRSA and MRSE) including:

  • Bacteremia/septicemia
  • Endocarditis (alone or combined with aminoglycosides for enterococcal endocarditis)
  • Bone and joint infections (including prosthetic joint infections when combined with rifampin) 3
  • Lower respiratory tract infections
  • Skin and skin structure infections
  • Early-onset prosthetic valve endocarditis (combined with rifampin and/or aminoglycosides) 2

• Penicillin-allergic patients with serious Gram-positive infections 1, 2

• Endocarditis caused by:

  • Viridans streptococci or S. bovis (alone or with aminoglycosides)
  • Enterococci (E. faecalis) - only in combination with aminoglycosides
  • Diphtheroids 2

• Surgical prophylaxis - only at institutions with high MRSA/MRSE rates for procedures involving prosthetic materials (cardiac, vascular, total hip replacement). Single dose before surgery, maximum two doses 1

Oral Vancomycin

Oral vancomycin is specifically indicated for Clostridioides difficile infection and staphylococcal enterocolitis 2. The most recent 2019 guidelines establish clear treatment algorithms:

• Severe CDI: Vancomycin 125 mg orally four times daily for 10 days is superior to metronidazole and is first-line therapy 4

• Moderate CDI: Vancomycin 125 mg four times daily for 10 days is now recommended as first-choice even for moderate cases, representing an evolution from older guidelines 4

• Recurrent CDI: For second and subsequent recurrences, vancomycin 125 mg four times daily for at least 10 days, with consideration of taper/pulse strategies 5

• Fulminant CDI: Higher doses (up to 500 mg four times daily) may be used, though evidence is limited. When oral route is impossible, vancomycin enemas (500 mg in 100 mL normal saline every 4-12 hours) plus IV metronidazole 4

Critical caveat: IV vancomycin has NO effect on CDI since it is not excreted into the colon 4. Only oral or intracolonic administration works.

Important Limitations - When NOT to Use Vancomycin

The 1995 HICPAC guidelines explicitly discourage vancomycin use in several situations to prevent resistance 1:

• NOT for routine surgical prophylaxis (except high MRSA institutions with prosthetic implants)
• NOT for empiric febrile neutropenia unless evidence of Gram-positive infection and substantial MRSA prevalence
• NOT for single positive coagulase-negative staph blood culture (likely contamination)
• NOT for catheter prophylaxis or colonization eradication
• NOT as primary treatment for antibiotic-associated colitis (metronidazole first for non-severe cases in resource-limited settings)
• NOT for convenience dosing in renal failure when beta-lactams would work

Organism Coverage

Vancomycin is active against 2, 6:

• Staphylococci (including MRSA, MRSE)
• Streptococci (including S. pneumoniae, S. pyogenes, S. agalactiae, viridans group)
• Enterococci (E. faecalis, though E. faecium may be resistant)
• Streptococcus bovis
• Diphtheroids
• Listeria monocytogenes
• Anaerobic Gram-positives (Actinomyces, Lactobacillus)
• Clostridioides difficile (oral route only)

Vancomycin has NO activity against: Gram-negative bacilli, mycobacteria, or fungi 2

Key Clinical Considerations

The "vancomycin creep" phenomenon—slow upward trending of MICs from <1 to 1.5-2 mcg/mL—is associated with high therapeutic failure rates, particularly in MRSA 6, 7. This has led to recommendations for AUC/MIC-targeted dosing of 400-600 (or 400-700) mg·h/L rather than simple trough monitoring 8, 9, 10.

Synergy exists when vancomycin is combined with aminoglycosides against many staphylococci, enterococci, and streptococci 2. For staphylococcal prosthetic joint infections, combining vancomycin with rifampin for 3 months after initial IV therapy improves outcomes 3.