Augmentin Coverage Spectrum
Yes, Augmentin (amoxicillin-clavulanate) provides broad-spectrum coverage against gram-positive, gram-negative, and anaerobic organisms through its beta-lactamase inhibitor activity. 1
Mechanism of Action
The combination of amoxicillin with clavulanic acid protects amoxicillin from degradation by beta-lactamase enzymes, effectively extending its spectrum to include many bacteria normally resistant to amoxicillin and other beta-lactam antibiotics. 1 This formulation possesses the properties of both a broad-spectrum antibiotic and a beta-lactamase inhibitor. 1
Gram-Positive Coverage
Augmentin demonstrates activity against key gram-positive organisms:
- Staphylococcus aureus (both beta-lactamase and non-beta-lactamase-producing strains), though methicillin/oxacillin-resistant staphylococci must be considered resistant 1
- Streptococcus pneumoniae with MICs of ≤2 mcg/mL against most strains (≥90%) 1
- Streptococcus pyogenes and viridans group streptococci 1
- Enterococcus faecalis 1
Gram-Negative Coverage
The drug covers important gram-negative pathogens:
- Escherichia coli (both beta-lactamase and non-beta-lactamase-producing) 1
- Haemophilus influenzae (both beta-lactamase and non-beta-lactamase-producing) 1
- Klebsiella species (all known strains are beta-lactamase-producing) 1
- Moraxella catarrhalis (both beta-lactamase and non-beta-lactamase-producing) 1
- Proteus mirabilis 1
- Enterobacter species (clinical efficacy demonstrated particularly in urinary tract infections) 1
Anaerobic Coverage
Augmentin provides robust anaerobic coverage:
- Bacteroides species, including Bacteroides fragilis (both beta-lactamase and non-beta-lactamase-producing) 1
- Fusobacterium species 1
- Peptostreptococcus species 1
- MICs of ≤4 mcg/mL against most (≥90%) strains of anaerobic bacteria 1
Clinical Applications
Beta-lactam/beta-lactamase inhibitor combinations like amoxicillin-clavulanate have in vitro activity against gram-positive, gram-negative, and anaerobe organisms. 2 The World Society of Emergency Surgery guidelines recognize amoxicillin-clavulanate as an option for mild community-acquired intra-abdominal infections. 2, 3
For intra-abdominal infections, antibiotics should be active against enteric gram-negative aerobic and facultative bacilli, beta-lactam-susceptible gram-positive cocci, and obligate anaerobic bacilli for distal small-bowel and colon-derived infections. 2 Augmentin meets these requirements for mild-to-moderate community-acquired infections. 2
Important Limitations
Critical caveats to consider:
- Pseudomonas aeruginosa is NOT covered by amoxicillin-clavulanate 4
- Enterobacter species, Proteus morgani, Serratia marcescens produce beta-lactamases less susceptible to clavulanic acid and are usually resistant 4
- Methicillin-resistant staphylococci must be considered resistant despite in vitro susceptibility 1
- In areas with high prevalence of ampicillin/sulbactam-resistant E. coli or fluoroquinolone-resistant organisms, local resistance patterns should guide therapy 2