Excerpt from article: In combination therapy, synergy is said to occur when the combined effect is greater than the sum of the individual effects. An additive effect is observed with the combined effect which is equal to the sum of the individual effects. Indifference is observed when there is no interaction between one another. Antagonism is defined when the combined effect is less than when the two compounds are individually applied. The reversal of resistance is said to occur when a synergistic outcome is observed. As an example, one of the strategies employed was to screen against β-lactamase producers and by mechanism-based inhibition of the active-site serine hydrolases for compounds that can antagonize the antibiotic-destroying hydrolases. Clavulanic acid (sulbactam or tazobactam) from a streptomycete in combination with amoxicillin was the outcome of this approach [34]. However, the victory against bacterial resistance did not last long; the frequent use of clavulanic acid ...