-population-will-develop-clinically-important-resistance-compared-to-monotherapy

Question

Why does combining a sulfonamide (enzyme A inhibitor) with trimethoprim (enzyme B inhibitor) reduce the probability that a bacterial population will develop clinically important resistance compared to monotherapy?

Accepted Answer

Because resistance would require simultaneous independent mutations or mechanisms conferring resistance to both drugs; inhibition at two sequential steps makes escape via a single mutation unlikely.

Answer

Because the two drugs chemically react with each other to form a new compound that irreversibly modifies bacterial DNA, making resistance mechanically impossible.

Answer

Because host immune responses are suppressed differentially by each drug, and suppression of immunity is what prevents the emergence of resistant bacterial clones during therapy.

Answer

Because combining two inhibitors increases the metabolic rate of the pathway so bacteria exhaust their substrates more quickly, preventing resistant mutants from growing.