Is Levaquin (levofloxacin) effective against Staphylococcus and Streptococcus infections?

Levofloxacin Coverage for Staphylococcus and Streptococcus

Yes, Levofloxacin (Levaquin) is effective against both Staphylococcus and Streptococcus infections, though its coverage is better for Streptococcus species than for some Staphylococcus strains, particularly methicillin-resistant Staphylococcus aureus (MRSA).

Antimicrobial Spectrum

According to the FDA drug label, levofloxacin is specifically indicated for:

• Methicillin-susceptible Staphylococcus aureus infections in multiple conditions including:

  • Nosocomial pneumonia
  • Community-acquired pneumonia
  • Acute bacterial exacerbation of chronic bronchitis
  • Complicated and uncomplicated skin and skin structure infections
  • Chronic bacterial prostatitis 1

• Streptococcus pneumoniae infections (including multi-drug resistant strains in some indications) in:

  • Community-acquired pneumonia
  • Acute bacterial sinusitis 1

• Streptococcus pyogenes in uncomplicated skin and skin structure infections 1

Efficacy Against Specific Pathogens

Streptococcus Coverage

Levofloxacin demonstrates excellent activity against Streptococcus species:

• Streptococcus pneumoniae (including penicillin-resistant strains) - levofloxacin is highly effective 2
• Streptococcus pyogenes (Group A strep) - good coverage 1
• Other streptococci - generally susceptible 3

Staphylococcus Coverage

Levofloxacin's activity against Staphylococcus is more variable:

• Methicillin-susceptible Staphylococcus aureus (MSSA) - good activity 3
• Methicillin-resistant Staphylococcus aureus (MRSA) - variable and increasing resistance 2
• Coagulase-negative staphylococci - variable susceptibility 3

Important Clinical Considerations

1. Increasing Resistance Concerns:

   • The prevalence of resistance to fluoroquinolones, including levofloxacin, appears to be increasing, particularly among Staphylococcus species 2
   • A study of over 3,200 ocular isolates found methicillin resistance in 42% of staphylococcal isolates, with high concurrent resistance to fluoroquinolones 2

2. Risk Factors for Resistance:

   • Recent fluoroquinolone use
   • Hospitalization
   • Advanced age
   • Recent ocular surgery 2

3. Comparative Efficacy:

   • Levofloxacin is more active against Gram-positive organisms than ciprofloxacin 4
   • However, newer fluoroquinolones like moxifloxacin and gatifloxacin may have better coverage against Gram-positive pathogens 2

4. Bactericidal Activity:

   • Levofloxacin demonstrates bactericidal activity against both Streptococcus pneumoniae and Staphylococcus aureus in human skin blister fluid studies 5
   • Time-kill studies show that levofloxacin has greater bactericidal activity against both pathogens compared to ciprofloxacin 3

Clinical Applications

For respiratory infections where Streptococcus pneumoniae is a common pathogen, levofloxacin is an excellent choice 2. For skin and soft tissue infections where both Streptococcus and Staphylococcus may be present, levofloxacin is effective for methicillin-susceptible Staphylococcus aureus and Streptococcus pyogenes 1.

However, for infections where MRSA is suspected or confirmed, alternative agents should be considered due to increasing resistance patterns 2.

In summary, while levofloxacin does cover both Staphylococcus and Streptococcus species, its effectiveness against Staphylococcus is increasingly limited by resistance, particularly in MRSA strains. For Streptococcus species, including penicillin-resistant Streptococcus pneumoniae, levofloxacin remains a reliable option.