11. Antimicrobial Resistance and Mechanism

11. Antimicrobial Resistance and Mechanism
Antimicrobial Resistance
~ Antimicrobial resistance is the ability of a microbe to resist the effects of antimicrobial previously used to treat them.
~ Antimicrobial resistance occurs when microbe change in response to the use of these agent.
~ Antimicrobial resistance leads to higher medical costs, prolonged hospital stays and increased mortality.
~ The world urgently needs to change the way it prescribes and uses antimicrobial agents.
~ If new antimicrobial agent is developed, without behaviour change, antimicrobial resistance will remain a major threat to the world.
~ Antimicrobial resistance is rising to dangerously high levels in all parts of the world.
Mechanism of Bacterial Resistance: -
• Enzymatic inactivation; e.g. ß-lactamase enzyme (Penicillinase) which inactivate Penicillin by hydrolysis of β-lactam ring.
• Impermeability to antibiotic; Many antibiotics enter the cell through protein channels called "Porin" absence or mutation or loss of a porins channel can slow the rate of drug entry into a cell or prevent entry.
• Efflux: Bacteria also have efflux pumps that can transport drugs out of the cell.
• Mutation; is a change in the DNA that can sometimes cause;
~ Decrease affinity of target enzyme.
~ Alteration of target site.
~ Over production of target site or metabolite.