Resistance of bacteria to anti-microbial drugs Production of enzymes that destroy or inactivate anti-microbials Eg. B.lactamase destroying B-lactam ring of penicillin
Altering permeability of bacterial cell membrane Eg. resistance to polymixin and tetracycline
Developing an altered structural target for the drug Eg. resistance to aminoglycosides and erythromycin
Developing an altered metabolic pathway that bypasses the reaction inhibited by the drugs Eg. resistance to sulfonamides
Developing an altered enzyme that can still perform its metabolic function but is much less affected by the drug Eg. resistance to trimethoprim
Dangers of indiscriminate use of antimicorbial drugs
Wide spread sensitization resulting in hypersensitivity and anaphylactic reaction, and drug rashes.
Changing normal microbial flora leading to “super infection” due to over growth of drug-resistant micro-organism.
Direct drug toxicity
Eg. renal and auditory nerve damage due to aminoglylosides toxicity.
Masking serious infection with out eradicating it.
Development of drug resistance by micro-organisms.