Amp resistance is an abbreviation for resistance to the antibiotic ampicillin. In modern usage an antibiotic is a Chemotherapeutic agent with activity against Microorganisms such as Bacteria, fungi or Protozoa Ampicillin is a beta-lactam Antibiotic that has been used extensively to treat bacterial Infections since 1961 It is used as a selectable marker in bacterial Philip Soltez. See antibiotic resistance