Antimicrobial drugs
Compounds that kill or control the growth of microorganisms in the host
Antimicrobial drugs
Compounds that kill or control the growth of microorganisms in the host
What kind of toxicity does antimicrobial drugs have?
Selective toxicity
Categories of antimicrobial drugs
Synthetic and natural
Growth factor analogs
Structurally similar to growth factors but do not function in the cells - analogs similar to vitamins, amino acids, and other compounds
Sulfa drugs were discovered by and when?
Gerhard Domagk in the 1930s
Sulfa drugs
Inhibit growth of bacteria by inhibiting folic acid synthesis and thus nucleic acid synthesis
Quinolones
Inhibit DNA gyrase, prevent DNA supercoiling
Quinolones are active against
Both gram-negative and gram-positve bacteria
What percentage of antibiotics are clinically useful?
Less than 1%
Beta-lactam antibiotics
Cell wall synthesis inhibitors
Beta-lactam antibiotics
Cell wall synthesis inhibitors
What kind of toxicity does antimicrobial drugs have?
Selective toxicity
Categories of antimicrobial drugs
Synthetic and natural
Growth factor analogs
Structurally similar to growth factors but do not function in the cells - analogs similar to vitamins, amino acids, and other compounds
Sulfa drugs were discovered by
Gerhard Domagk in the 1930s
Sulfa drugs
Inhibit growth of bacteria by inhibiting folic acid synthesis and thus nucleic acid synthesis
Quinolones
Inhibit DNA gyrase, prevent DNA supercoiling
Quinolones are active against
Both gram-negative and gram-positve bacteria
Antibiotics are produced by
Bacteria and fungi
What percentage of antibiotics are clinically useful?
less than 1%
Beta-lactam antibiotics
Cell wall synthesis inhibitors
What comprises over 50% of antibiotics used around the world?
Beta-lactam antibiotics
Who discovered penicillin?
Alexander Fleming
What do penicillins target?
cell wall (peptidoglycan synthesis) or transpeptidation
What are examples of a beta-lactam antibiotic?
Penicillin
What is penicillin effective against?
Gram-positive
Some synthetic forms active against gram-negative
Cephalosporins are made of?
Fungus
What do cephalosporins target?
Cell wall synthesis
What is more broad spectrum: penicillin or cephalosporin?
Cephalosporin
Cephalosporins are resistant against?
Beta-lactamases
Cephalosporins are used to treat
Gonorrhea
Aminoglycosides are bonded by
Glycosidic linkages
Examples of aminoglycosides ar
Streptomycins, kanamycin, neomycin, and gentamycin
What do aminoglycosides target?
30S subunit of ribosome
Why aren’t aminoglycosides commonly used?
They lack selective toxicity
What are the antibiotics from bacteria?
Aminoglycosides, macrolides, tetracyclines, daptomycin, cyclic lipopeptide, and platensimycin
Macrolide structure
Lactone rings bonded to sugars
Example of macrolide
Erythromycin (Streptomyces erythreus)
Macrolides have what kind of spectrum
Broad
What do macrolides target?
50S subunit of ribosome
Mechanism of macrolides
Inhibition of protein synthesis
Preferential translation of some proteins
Tetracyclines are produced by
Several species of Streptomyces
What kind of spectrum do tetracyclines have?
Broad spectrum
What kind of drug are tetracyclines?
Natural and semisynthetic
What do tetracyclines inhibit?
30S subunit of ribosome
What are the most widely used antibiotics?
Tetracyclines and penicillin
What antibiotic is veterinary?
Tetracyclines
What antibiotic is highly resistant?
Tetracyclines
What are the novel antibiotics?
Daptomycin, cyclic lipopeptide and platensimycin
What produces daptomycin?
Streptomyces
What is cyclic lipopeptide active against?
Gram-positive
How do daptomycin and cyclic lipopeptide work?
They form pores in the cellular membrane that leads to depolarization
How does platensimycin work?
Fatty acid biosynthesis inhibitor - no host toxicity
What antibiotic target MRSA and VRE?
Platensimycin
What percent of antibiotics are used in agricultural practices?
80%
Mechanisms of resistance for microorganisms
Reduced permeability Inactivation of antibiotic Alternation of target Development of resistant biochemical pathway Efflux