Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation prepared by Christine L. Case Microbiology B.E Pruitt & Jane J. Stein AN INTRODUCTION EIGHTH EDITION TORTORA FUNKE CASE Chapter 20, part B Antimicrobial Drugs
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Polyenes Amphotericin B Azoles Miconazole Triazoles Allylamines Antifungal Drugs Inhibition of Ergosterol Synthesis Figure 20.15
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Echinocandins Inhibit synthesis of -glucan Cancidas is used against Candida and Pneumocystis Antifungal Drugs Inhibition of Cell Wall Synthesis
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Flucytocine Cytosine analog interferes with RNA synthesis Pentamidine isethionate Anti-Pneumocystis; may bind DNA Antifungal Drugs Inhibition of Nucleic Acids
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Griseofulvin Used for superficial mycoses Tolnaftate Used for athlete's foot; action unknown Antifungal Drugs Inhibition of Microtubules (Mitosis)
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Antiviral Drugs Nucleoside and Nucleotide Analogs Figure 20.16a
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Antiviral Drugs Nucleoside and Nucleotide Analogs Figure 20.16b, c
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Protease inhibitors Indinavir HIV Inhibit attachment Zanamivir Influenza Inhibit uncoating Amantadine Influenza Interferons prevent spread of viruses to new cells Viral hepatitis Antiviral Drugs Enzyme Inhibitors
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Chloroquine Inhibits DNA synthesis Malaria Diiodohydroxyquin Unknown Amoeba Metronidazole Damages DNA Entamoeba, Trichomonas Antiprotozoan Drugs
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Niclosamide Prevents ATP generation Tapeworms Praziquantel Alters membrane permeability Flatworms Pyantel pamoate Neuromuscular block Intestinal roundworms Antihelminthic Drugs
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Mebendazole Inhibits nutrient absorption Intestinal roundworms Ivermectin Paralyzes worm Intestinal roundworms Antihelminthic Drugs
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Disk-Diffusion Test Figure 20.17
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings E Test Figure 20.18
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings MIC Minimal inhibitory concentration MBC Minimal bactericidal concentration
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Broth Dilution Test Figure 20.19
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20.20
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings A variety of mutations can lead to antibiotic resistance. Mechanisms of antibiotic resistance 1. Enzymatic destruction of drug 2. Prevention of penetration of drug 3. Alteration of drug's target site 4. Rapid ejection of the drug Resistance genes are often on plasmids or transposons that can be transferred between bacteria. Antibiotic Resistance
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Misuse of antibiotics selects for resistance mutants. Misuse includes: Using outdated, weakened antibiotics Using antibiotics for the common cold and other inappropriate conditions Use of antibiotics in animal feed Failure to complete the prescribed regimen Using someone else's leftover prescription Antibiotic Resistance
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synergism occurs when the effect of two drugs together is greater than the effect of either alone. Antagonism occurs when the effect of two drugs together is less than the effect of either alone. Effects of Combinations of Drugs
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Effects of Combinations of Drugs Figure 20.22
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Antimicrobial peptides Broad spectrum antibiotics from plants and animals Squalamine (sharks) Protegrin (pigs) Magainin (frogs) Antisense agents Complementary DNA or peptide nucleic acids that binds to a pathogen's virulence gene(s) and prevents transcription The Future of Chemotherapeutic Agents