Bacterial Resistance to Antibiotics:
Producing an Altered Target Site to which the Antibiotic no Longer Binds

A bacterium can become resistant to an antibiotic by altering the antibiotic's target site, in this case the antibiotic-binding site of the bacterial enzyme. Since the drug is no longer able to bind to the enzyme, the active site of the enzyme is not altered and the enzyme is able to bind to its normal substrate.