This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: JIPMER 2019, Subject name: Pharmacology
Mechanism of resistance of tetracyclines is due to? 
Select and explain. 
A. Drug efflux mechanism, B. Development of inactivating enzymes, C. DNA methylation, D. Cell wall alteration
A: Drug efflux mechanism
Answer: A: Drug efflux mechanism 
Explanation: Mechanism of Resistance Examples Enzymatic breakdown A: Aminoglycosides B: Beta lactams C: Chloramphenicol Decreased permeability Aminoglycosides Efflux pumps Tetracyclines Altered metabolic pathway Sulfonamides Altered target MRSA Vancomycin, Fluoroquinolones