prepared synthetically in the lab
Antibiotics are of of bacteria and fungi
Classification of antibacterial agents
A- According to spectrum: 1- spectrum 2- spectrum
B- According to the antibacterial effect 1- 2-
C- According to mechanism of action: 1- Inhibition of 2- Inhibition of 3- Inhibition of 4- Inhibition of 5- Inhibition of
Target receptor for Inhibition of cell wall synthesis
Penicillin binding proteins
cytoplasmic membrane
Mycoplasma
Pseudomonas
2 groups for Inhibition of cell wall synthesis
1. drugs 2. &
β Lactam drugs
Penicillin
cephalosporin
polymyxin
polyene
Penicillins & cephalosporins inhibit early precursors in transpeptidation
& inhibit early precursors in transpeptidation
advantage of β Lactam drugs
Bactericidal
Selective toxicity
can act on non growing cells
bacitracin act only on growing cells
Inhibition of cell membrane function drugs
polymyxins
polyenes
Amikacin
Tetracyclines
Advantages of polymyxins & polyenes
1. ❌ 2. ❌
Disadvantage of polymyxins & polyenes
1. ❌
Drugs acting on the 30S ribosomal subunit
Gentamicin
Lincomycin
Erythromycin
oleandomycin
Aminoglycosides
1. 2.
Tetracyclines effective in treatment of Chlamydophila
oleandomycin is effective in treatment of intracellular bacteria
Tetracyclines: Effective in treatment of intracellular bacteria e.g. &
Aminoglycosides are Bactericidal Bacteriostatic( Bactericidal, Bacteriostatic )
Tetracyclines are Bacteriostatic Bactericidal( Bacteriostatic, Bactericidal )
Drugs acting on the 50S ribosomal subunit except
Chloramphenicol
Macrolides
Drugs acting on the 50S ribosomal subunit are Bacteriostatic Bactericidal( Bacteriostatic, Bactericidal )
Inhibition of nucleic acid synthesis
Rifampin: inhibit
Quinolones: inhibit
Rifampin Quinolones oleandomycin( Rifampin, Quinolones, oleandomycin ): inhibit DNA dependent RNA polymerase
Inhibition of bacterial metabolism
Sulphonamides: inhibit
Trimethoprim: inhibits
Trimethoprim: inhibits DHFA synthetase
Bacterial Resistance to chemotherapeutic agents
1. (natural/inherent) 2. (acquired)
Genetic origin (acquired inherent( acquired, inherent )) is Unpredictable predictable( Unpredictable, predictable )
Genetic origin () 1- (=change in ) 2- ( carrying destroying enzymes
Non genetic origin (/inherent) , 1- Absence of cell wall () 2- Permeability barrier in cell envelope () 3- Non multiplying ()
Mechanisms of Resistance
1. 2. 3. e.g.s, , 4. ()
Bacteria resistant to a drug may be resistant to a one.
Antibacterial Drug Combinations
1- ❌ ( 1 + 1= 1 ) 2- ❌ (1 + 1 = 2 ) 3- ❌ ( 1 + 1= 3 ) 4- ❌ ( 1 + 1= 0 )
Synergism
❌ + ❌ ❌ + aminoglycoside ❌ + ❌
Control of Drug Resistance
1- Give only when 2- Proper choice (according to ) 3- Give in the proper for proper (To prevent ) 4- Use drug (simultaneous use of 2 drugs) 5- Avoid of drugs
