Antimicrobial Drugs PDF

Superbugs Resistant to a wide range of antibiotics Carry antibiotic resistant genes Extremely hard to cure ESKAPE pathogens  28.10 Antimicrobial Drugs Antibiotics are naturally occurring antimicrobial compounds that are produced by fungi or Bac...

Superbugs Resistant to a wide range of antibiotics Carry antibiotic resistant genes Extremely hard to cure ESKAPE pathogens  28.10 Antimicrobial Drugs Antibiotics are naturally occurring antimicrobial compounds that are produced by fungi or Bacteria. In order to be useful, antibiotics need to exhibit selective toxicity, meaning these drugs target pathogens while leaving host cells and tissues relatively unharmed. Antibiotics are classified by their mechanism of action, as each group targets different parts of bacterial anatomy or physiology. (Figure 28.27) The susceptibility of microbes to different antibiotics varies greatly. – Gram-positive and gram-negative Bacteria vary in their sensitivity to antibiotics. – Broad-spectrum antibiotics are effective against both groups of Bacteria. 여 Antibiotics mechanisms of action Exam ) Which antibiotiks is used here ? 4choces ∅ θ Conly in microbe) I Look at what is microbe cell special in diflevert/ Figure 28.27  exam) skip ( no Ideas Target sigma factors Identify mutations and genetic tools like CRISPR to target those mutations. Radiation therapy specific for microbes Little “nano-robot” – identify microbes (surface protein) and kill them Virus targeting microbe delivering some DNA that produce many stuff Targeting proteins on the cell surface e.g., Antibody. Plasma therapy, photo Signal molecules Disruption the binding of RNA polymerase to DNA based on charge and Mg2+ ion Screen drug with new mechanism AI aid Toxin inhibition – inhibit production; compounds inhibitors; antibody; export Target cellular inclusions Novel artificial transcription factors Novel enzymes to digest the cell wall Engineer microbe to destroy biofilm 7  ∠ Figure 28.28b # No exam Antibiotic treatment terminology Antibacterial spectrum: Range of activity of an antimicrobial against bacteria. A broad-spectrum antibacterial drug can inhibit a variety of gram-positive and gram-negative bacteria, whereas a narrow-spectrum drug is active against a limited variety of bacteria. Bacteriostatic activity: Level of antimicrobial activity that inhibits the growth of an organism. This is determined in vitro by testing a standardized concentration of organisms against a series of antimicrobial dilutions. The lowest concentration that inhibits the growth of the organism is referred to as the minimum inhibitory concentration (MIC). Bactericidal activity: Level of antimicrobial activity that kills the test organism. This is determined in vitro by exposing a standardized concentration of organisms to a series of antimicrobial dilutions. The lowest concentration that kills 99.9% of the population is referred to as the minimum bactericidal concentration (MBC).  Antibiotic combinations: Combinations of antibiotics that may be used to (1) broaden the antibacterial spectrum for empirical therapy or the treatment of polymicrobial infections, (2) prevent the emergence of resistant organisms during therapy, and (3) achieve a synergistic killing effect. Antibiotic synergism: Combinations of two antibiotics that have enhanced bactericidal activity when tested together compared with the activity of each antibiotic. Antibiotic antagonism: Combination of antibiotics in which the activity of one antibiotic interferes with the activity of the other (e.g., the sum of the activity is less than the activity of the most active individual drug).