M8

• Narrow Spectrum

  • drugs that are effective against few types of bacteria
• Broad Spectrum

  • drugs that are effective against several different classes of bacteria. Both + and -
• Extended Spectrum

  • effective against Gram-positive organism and a significant number of Gram-negative organisms
• Bactericidal

  • killing of microorganism
• Bacteriostatic

  • inhibition of metabolism and reproduction of microorganism
• Inhibition of cell wall synthesis:

  • Penicillin, Cephalosporins, Bacitracin, Vancomycin
• Inhibition of protein synthesis

  • Chloramphenicol, Erythromycin, Tetracyclines, Streptomycin
• Inhibition of nucleic acid replication and transcription

  • Quinolones, rifampin
• Injury to plasma membrane

  • polymyxin B
• Inhibition of essential metabolite synthesis

  • Sulfanilamide, trimethoprim
• PBP 1a and 1b

  • a transpeptidases involved in peptidoglycan synthesis associated with cell elongation
• PBP 2

  • involved in maintaining the rod shape of bacilli
• PBP 3

  • required for septum formation during cell division
• PBP 4 through 6

  • carboxypeptidases responsible for the hydrolysis of D-alanine-D-alanine terminal peptide bonds of the cross-linking peptides
• Binds to 30s ribosomes

  • Aminoglycoside
  • Tetracyline

  Binds to 50s ribosomes

  • Chloramphenicol
  • Erythromycin/ Macrolides
  • Lincosamide
• Disk Diffusion Chemotherapy

  • Kirby-Bauer test
  • a bacterial culture is inoculated on an agar medium, and filter paper disks impregnated with chemotherapeutic are overlaid on the culture.
• Broth Dilution Tests

  • In a broth dilution test, the microorganism is grown in liquid media containing different concentrations of a chemotherapeutic agent
• Multidrug Therapy

  • used simultaneously to kill all the pathogens and to prevent resistant mutant pathogens from emerging
• Amoxicillin + Clavulanic acid= Co-Amoxiclav (Augmentin)

  Ticarcillin + Clavulanic Acid= Timentin

  Ampicillin + Sulbactam= Unasyn

  Pipercillin + Tazobactam= Piper-Tazo, Tazoan, Piptaz
• Superbugs

  • refer to an organism that is resistant to only one antimicrobial agent, the term usually refers to multidrug resistant organisms
• Penicillinases

  • destroy the B-lactam ring in penicillins; thus, an organism that produces penicillinase is resistant to penicillin

  Cephalosporinases

  • destroy the B-lactam ring in cephalosporins; thus, an organism that produces cephalosporinases is resistant to cephalosporins
• B-lactamase inhibitor

  • the B-lactam inhibitor irreversibly binds to and inactivates the b-lactamase, thus enabling the companion drug to enter bacterial cell and disrupt cell wall synthesis