Final answer:
Resistant bacteria to sulfonamide have a greater affinity for a bacterial metabolic enzyme rather than the sulfonamide itself, the enzymes help them to circumvent the inhibitory effects of the drug.
Step-by-step explanation:
Bacteria that are resistant to sulfonamide have enzymes with a greater affinity for the bacterial metabolic enzyme targeted by the sulfonamide, specifically sulfihydropteroate synthase. This enzyme is important for the synthesis of dihydrofolic acid, which is a precursor for folic acid necessary for bacterial growth. The sulfonamides, being structural analogs and competitive antagonists of para-aminobenzoic acid (PABA), interfere with this process in sensitive bacteria. However, resistant bacteria may overproduce the target enzyme in amounts sufficient to allow the necessary enzymatic reactions to occur despite the presence of sulfonamides. Alternatively, they may develop a bypass mechanism that renders the inhibition by sulfonamides ineffective. As a result, the resistant bacteria will continue to grow even in the presence of these synthetic antibiotics.