Question

All BUT WHICH of the following are considered mechanisms of antibiotic resistance?

	1.	chemically altering the drug target site
	2.	prevention of drug penetration through the cell wall
	3.	production of enzymes that destroy the antibiotic
	4.	protein pump that ejects the drug from the cell
	5.	chemotherapeutic antagonism

Answer 1

Ans:- mechanism 1 to 4 are responsible for antibiotic resistance. explanations are as follow

1. chemically altering the drug target site:- in this mechanism bacteria alter binding site of target protein for example methicillin resistance staphylococcus bacteria (MRSA) alter penicillin binding protein (PBP) at which penicillin binds and produce its effect. another example is ribosomal alteration, many bacteria work by inhibiting protein synthesis by binding at ribosome, alteration ribosome binding site lead to bacterial resistance to that antibiotic.

2. prevention of drug penetration through the cell wall:- in this type of mechanism bacteria prevent uptake of antibiotic into cell by altering cell membrane permeability.

3. production of enzyme that destroy the antibiotic:- example is penicillin resistance bacteria which produce beta lactamase enzyme which degrade penicillin antibiotic and develop resistance against penicillin. to overcome this resistance beta lactamase inhibitor like clavulanic acid is prescribed along with amoxicillin.

4. protein pump that ejects the drug from the cell :- in this mechanism bacterial cell prevent accumulation of drug inside bacterial cell by activating protein that pump out drug. therefore not enough drug is present to produce its action for example fluoroquinolone resistance bacteria.