A hospital witnessed an outbreak of a nosocomial (hospital-acquired) infection caused by Klebsiella pneumoniae. It showed resistance to antibiotics generally used for its treatment. Under the given scenario, the antibiotic resistance of this organism can be attributed to

• Correct answer
  A

  the presence of antibiotic resistance gene acquired through horizontal transfer from other prevalent strains in the hospital.
• B

  silent mutations in target sites of antibiotics.
• Correct answer
  C

  neutralisation of antibiotics by enzymes that target and inactivate these antibiotics.
• Correct answer
  D

  reduced permeability of these antibiotics due to the formation of a protective barrier.

Hence, the correct answer is options: 'A', 'C', 'D'.