What bacterial infections does clindamycin cover?

Clindamycin Antimicrobial Coverage

Clindamycin provides excellent coverage against anaerobic bacteria and gram-positive organisms, including most Staphylococcus aureus strains and streptococci, but has no activity against most gram-negative aerobic bacteria. 1

Spectrum of Activity

Gram-Positive Bacteria (Excellent Coverage)

• Staphylococcus aureus (methicillin-susceptible strains) 1
• Streptococcus species:
  • Streptococcus pyogenes (Group A) 1
  • Streptococcus pneumoniae (penicillin-susceptible strains) 1
  • Other streptococci (Groups B, C, G) 2

Anaerobic Bacteria (Excellent Coverage)

• Peptostreptococcus species 3
• Clostridium perfringens 1
• Fusobacterium species (necrophorum, nucleatum) 1
• Prevotella melaninogenica 1
• Bacteroides species (particularly beta-lactamase-producing strains) 4
• Other anaerobes including:
  • Actinomyces israelii 1
  • Cutibacterium acnes 1
  • Eggerthella lenta 1

No Significant Activity Against

• Most gram-negative aerobic bacteria (e.g., E. coli, Pseudomonas) 1, 4
• Enterococci 5

Clinical Applications

Clindamycin is indicated for treating serious infections caused by susceptible organisms in:

1. Skin and Soft Tissue Infections:

   • Particularly effective against S. aureus and streptococcal infections 2
   • Used for MRSA when susceptible 2
   • Necrotizing fasciitis (especially when combined with penicillin for Group A streptococcal infections) 3

2. Respiratory Tract Infections:

   • Empyema, anaerobic pneumonitis, and lung abscess 1

3. Intra-abdominal Infections:

   • Peritonitis and intra-abdominal abscess 1

4. Female Genital Tract Infections:

   • Endometritis, tubo-ovarian abscess, and pelvic inflammatory disease 2, 1
   • Often combined with gentamicin for polymicrobial coverage 6

Important Clinical Considerations

Mechanism of Action

Clindamycin inhibits bacterial protein synthesis by binding to the 23S RNA of the 50S ribosomal subunit. It is bacteriostatic rather than bactericidal 1.

Resistance Concerns

• Resistance to clindamycin is most often caused by modification of specific bases of the 23S ribosomal RNA 1
• Cross-resistance between clindamycin and lincomycin is complete 1
• Macrolide-inducible resistance to clindamycin occurs in some isolates (requires D-zone testing) 1

Major Adverse Effect

• Clostridioides difficile-associated diarrhea (pseudomembranous colitis) is a significant concern 2, 1
• This complication typically responds to discontinuation of clindamycin and treatment with vancomycin or metronidazole 4

Combination Therapy

When broader coverage is needed (particularly for mixed infections):

• Clindamycin + aminoglycoside (e.g., gentamicin) for coverage of gram-negative organisms 5, 6
• Clindamycin + penicillin for Group A streptococcal necrotizing fasciitis 3

Dosing

• For serious infections: 600-900 mg intravenously every 8 hours 4
• Oral dosing: 300-450 mg every 6-8 hours 1

Clindamycin remains a valuable antibiotic in the treatment of serious anaerobic and gram-positive infections, particularly when penicillins are contraindicated. However, its lack of activity against gram-negative aerobic bacteria often necessitates combination therapy for mixed infections.