ASIF BIOTECH

Basic Mechanisms of Antibiotic Action and Resistance Five Basic Mechanisms of Antibiotic  Action against Bacterial Cells: 1. Inhibition of Cell Wall Synthesis (most common mechanism) 2. Inhibition of Protein Synthesis (Translation) (second largest class) 3. Alteration of Cell Membranes 4. Inhibition of Nucleic Acid Synthesis 5. Antimetabolite Activity   Inhibition of Cell Wall Synthesis Beta-Lactams ---> Inhibition of peptidoglycan synthesis (bactericidal) Resistance ---> (1)      fails to cross membrane (gram negatives) (2)      fails to bind to altered PBPs (3)      hydrolysis by beta-lactamases Vancomycin ---> Disrupts peptidoglycan cross- linkage Resistance ---> (1)      fails to cross gram negative outer membrane (too large) (2)      some intrinsically resistant (pentapeptide terminus) Bacitracin ---> Disrupts movement of peptidoglycan precursors (topical use) Resistance ---> fails to penetrate

MOA                  of   Aminoglycoside             Antibiotics Aminoglycosides exert their bactericidal effect by inhibiting protein synthesis in bacteria and compromising the structure of the bacterial cell wall . Aminoglycoside Antibiotics Aminoglycoside antibiotics are used to treat serious infections caused by gram-negative bacteria . Some commonly used aminoglycosides include: amikacin (Amikin®); apramycin; capreomycin; gentamicin (Garamycin®); kanamycin (Kantrex®); neomycin (Mycifradin®); netilmicin (Netromycin®); paromomycin (Humatin®); streptomycin; tobramycin (TOBI Solution®, TobraDex®, Nebcin®) Mode of Action Although aminoglycosides stop bacteria from making proteins, it is uncertain whether this is the action that results in bacterial cell death.     Disruption of Protein Synthesis A minoglyco s i d e s b i n d to the b a c t er i al 3 0 S r i b o s o mal s ubunit. R i b o s om e s are the p ro t e i n