Antibacterial

• Antibiotics


  It is mainly used in the treatmen of infectious disease
• Adverse


  Unexpected effects
• Erythromycin - It was first isolated from Saccharopolyspora erythraea in 1952.
• Broad Spectrum


  Wide coverage against several numbers of bactera
• Narrow Spectrum


  Effective to a limited number of microorganisms
• Bactericidal 


  Capable of killing the bacteria
• Bacteriostatic 


  Inhbit the growth of the bacteria
• Local Acting


  Limits its action on the site. Ex: Eye drops
• Systemic Acting


  Antibiotics are administered IM or IV
• Vancomycin


  Bacterial Cell wall will not develop
• Cell membrane


  It is important for survival of the organisms
• Cephalosporin


  These are a group of semisynthetic antibiotics
• Cationic, Anionic, and Neutral 


  Agents that target the cell membrane
• Inhibit Protein Synthesis 


  Binds with the ribosomes and their subunits
• Chloramphenicol


  a bacteriostatic agent that is effective against a number of gram-positive and gram-negative organisms.
• Macrolides


  the most popular macrolide is erythromycin which can effectively inhibit certain gram-positive and gram-negative bacteria.
• azithromycin and clarithromycin


  Newer classes of macrolides are:
• Linconoids


  Agents that bind with both 30S and 50S ribosome sub-units include gentamycin and kanamycin
• Clindamycin


  The most important among the lincinoids
• Topoisomerase Enzymes


  are essential to DNA Synthesis and are critical enzymes involved in protein translation and cell replication
• Quinolones


  Have been found to be most effective against DNA gyrase
• Nalidixic Acid and Oxolinic Acid


  First generation quinolones
• Fluoroquinolones


  Which have a wider spectrum of activity than the quinolones
• Rifampicin


  Is a first line drug used for the treatment of tuberculosis that specifically inhibits bacterial RNA SYNTHESIS
• Trimethoprim and sulfonamides


  are antibiotics that interfere with folic acid metabolism.
• Tetrahydro folic acid 


  is important in the synthesis of DNA, RNA , and bacterial cell wall proteins.
• Bacteria 


  cannot utilize preformed folic acid from the environment and thus must synthesize their own.
• Sulfonamides 


  act specifically by inhibiting formation of dihydro folic acid.
• Drug Resistance 


  is a growing concern in the filed of infectiom
• Drug resistance 


  is a growing concern in the field of infection control.
• Intrinsic resistance


  is a stable genetic property that is encoded in the chromosome of the organism and shared by all strains of the species.
• Acquired resistance 


  is resistance arising from the ability of an organism to resist an antimicrobial drug to which the species, as a whole, is naturally susceptible.
• Transformation 


  simplest and the earliest form of genetic exchange studied. In it, free microbial DNA inserts itself into the DNA of the same species
• Transduction 


  the transfer of genetic material by a bacteriophage
• Conjugation 


  transfer of genetic material through the sex pilus. What is transferred to another bacterium is an extrachromosomal DNA called plasmid. The resistance gene is carried by the plasmid.
• Resistance Gene


  it may code for enzymes that can alter its chemical structure leading to the inactivation of the antibiotic, or the production may cause hydrolysis of the antibiotic thereby destroying the antibiotic.
• Gram-negative bacteria 


  have developed the ability to change the lipid composition of their outer membrane thereby preventing the antibiotic from reaching its cellular target.
• Streptococcus pneumoniae 


  has developed resistance to penicillin by causing alteration in the structure of its penicillin-binding protein.
• Mycobacterium tuberculosis 


  produces a protein that can be mistaken for the structure of DNA.