Antimicrobial Agents
Mechanism of Action According to classification
Sulfonamide
Most bacteria produce its own folic acid (FA) of which Para Amino Benzoic Acid (PABA) is a constituent. Antimicrobial agents, Sulfonamide has similar structure like PABA. So, by interfering, it inhibits to produce actual folic acid and form an alternate folate which is metabolically injurious to bacteria.
Most bacteria produce its own folic acid (FA) of which Para Amino Benzoic Acid (PABA) is a constituent. Antimicrobial agents, Sulfonamide has similar structure like PABA. So, by interfering, it inhibits to produce actual folic acid and form an alternate folate which is metabolically injurious to bacteria.
Example:
Sulfadiazine, Para amino salicylic Acid (PAS).
.
Beta Lactum
Antibiotics
This antimicrobial agents are bactericidal. It interferes with the last step of bacterial cell wall synthesis called transpeptidation by inhibiting the transpeptidase enzyme. So that cross linking does not take place. And resulting in exposure of less stable membrane. Cell lysis can occur then through osmotic pressure.
This antimicrobial agents are bactericidal. It interferes with the last step of bacterial cell wall synthesis called transpeptidation by inhibiting the transpeptidase enzyme. So that cross linking does not take place. And resulting in exposure of less stable membrane. Cell lysis can occur then through osmotic pressure.
Example:
Penicillin (Pen-G,Pen-V,Amoxicillin), Cephalospirin (Cefazolin, Cefuroxime,
Cefixime, Cefepime).
Protein
Synthesis inhibitor
Entry of these antimicrobial agents in organism caused by diffusion. The drugs bind to the 30s subunit of bacterial ribosome and blocking the access of amino acyl t-RNA to the m-RNA ribosome complex at the receptor site. And protein synthesis inhibited.
Entry of these antimicrobial agents in organism caused by diffusion. The drugs bind to the 30s subunit of bacterial ribosome and blocking the access of amino acyl t-RNA to the m-RNA ribosome complex at the receptor site. And protein synthesis inhibited.
Example:
Tetracycline, Doxicycline.
Aminoglycoside: Antimicrobial agents, Aminoglycoside transport
through bacterial cell wall by diffusion and cytoplasmic membrane. Then it will
bind to ribosome of bacteria, that will result, inhibition of protein
synthesis.
Example:
Neomycin, Streptomycin.
Macrolide: This antimicrobial agents bind irreversibly to a site
on the 50s subunit of the bacterial ribosome, thus inhibiting the translocation
steps of protein synthesis. They also interfere transpeptidation.
Example:
Azithromycin, Erythromycin, Clarithromycin.
Chloramphenicol: This antimicrobial agents bind to the
bacterial 50s ribosomal subunit and inhibits protein synthesis at the peptidyl
transferase reaction.
Inhibitor of nucleic acid synthesis & function
Fluoroquinolone: It enters the cell by
diffusion through water-fluid protein channel (porin) in outer membrane.
Inhibit the replication of bacterial DNA by interfering with action of DNA
gyrase during bacterial growth and reproduction.
Example:
Ciprofloxacin, Ofloxacin.
Quinolone: Mechanisn of action is same
like fluoroquinolone, but not
fluorinated. Mainly used for gram(-) bacteria, that cause UTI.
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