Amoxicillin is similar to ampicillin in its bactericidal action against susceptible organisms during the stage of active multiplication. It acts through the inhibition of biosynthesis of cell wall mucopeptide. Amoxicillin has been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section.

Aerobic Gram-Positive Microorganisms

• Enterococcus faecalis

• Staphylococcus spp.† (β-lactamase-negative strains only)

• Streptococcus pneumoniae

• Streptococcus spp. (α- and β-hemolytic strains only)

† Staphylococci which are susceptible to amoxicillin but resistant to methicillin/oxacillin should be considered as resistant to amoxicillin.

Aerobic Gram-Negative Microorganisms

• Escherichia coli (β-lactamase-negative strains only)

• Haemophilus influenzae (β-lactamase-negative strains only)

• Neisseria gonorrhoeae (β-lactamase-negative strains only)

• Proteus mirabilis (β-lactamase-negative strains only)

Helicobacter

• Helicobacter pylori