∞ generated and posted on 2016.03.20 ∞

Less than sum-of-the-parts effectiveness of two antibiotics when used in combination.

Note that either one or both of the antibiotics may display reduced antimicrobial ability when used in combinations versus when used alone. The basic idea is that one of the antibacterial agents interferes with the activity of the other agent. For example, because bactericidal agents often are more effective against growing (log-phase) bacteria, the presence of bacteriostatic agents can interfere with bactericidal activity.