Lecture 13: Chemotherapeutic Agents and Antibiotics Flashcards

Terms Definitions
chemotherapeutic agents
A chemical that has been sythesized by chemists in a lab or produced by a modification of a preexisting chemical that kills microorganisms.
a product of the metabolism of a microorganism
What is the objective of a selectively toxic drug?
to kill or inhibit a pathogen while damaging the host as little as possible
What three things does the degree of selective toxicity depend on?
- therapeutic dose- toxic dose- therapeutic index
Therapeutic dose
drug level required for clinical treatment of a particular infection need enough of the drug to kill a pathogen so it can't establish disease
toxic dose
drug level when undesirable effects are produced-make extremely sick
Therapeutic index
toxic dose/ therapeutic dosehigher therapeutic index, better chemotherapeutic agent
higher therapeutic index, _____ chemotherapeutic agent
____ drugs are narrow-spectrum, while ___ are broad-spectrum
most- narrow-spectrumsome- broad-spectrum
Most drugs are narrow-spectrum. They treat ____
only one type of microbe
ISONIAZID is good for tuberculosis. It won't work for something else like a sinus infection. Is it narrow or broad spectrum?
_____ is a narrow spectrum drug that is good for tuberculosis.
Some drugs are broad-spectrum. Name three different broad-spectrum drugs.
Nemomycin is effective against what bacteria?
gram + and -
Zeocin is a broad-spectrum drug that is _____ AND ____
anti-bacterial and anti-fungal
Sulfonamides is a broad-spectrum drug that is _____, _____, and _____
kills target pathogen
reversibly inhibits growth of pathogen
What is the difference between bactericidal and bacteriostatic?
bactericidal kills. bacteriostatic inhibits.
Antibiotics can be of what three types?
Natural antibiotics are _____
produced by some living organism
Streptomyces is a living organism that makes what three natural antibiotics?
Streptomycin, chlortetracycline, and erythromycin are natural antibiotics made by what living organism?
streptomyces*Streptomyces is a bacterium
What living organism makes the natural antibiotic, penicillin?
penicillium *penicillium is a fungus*penicillin inhibits bacterial growth
Synthetic antibiotics are what?
manufactured from non-natural products. They are chemotherapeutic agents.
Give two examples of synthetic antibiotics.
Semi-synthetic antibiotics are what?
chemical modification of natural antibiotics
Give an example of semi-synthetic antibiotics
penicillin derivatives: ampicillin, carbenicillin, methicillin
Name three penicillin derivatives
ampicillincarbenicillinmethicillin* a lot of ppl are allergic to penicillin, so make penicillin derivatives in the lab
What are the 5 mechanisms of antimicrobial action?
- protein synthesis- nucleic acid- cell wall- cell membrane- metabolic reactions
There are 5 things you can target (protein synthesis, nucleic acid, cell wall, cell membrane, metabolic reactions), that kills microbes, but not ____
but not necessarily the host
What does polymyxin B disrupt?
Cell membrane*cell membrane is the site of where to attack a microbacterium
Is polymyxin B natural, synthetic, or semi-synthetic?
Polymyxin B is a natural antibiotic that comes from ____
What is polymyxin B effective against?
Gram - bacteria (P. aeruginosa)
Polymyxin B is effective against Gram- bacteria. Give an example
P. aeruginosa
What does polymyxin B do?
Binds cell membrane components, alters membrane permeability (causing cell leakage, death)
Polymyxin B can be found in ______ and _____
bacitracin (Gram +) and neomycin (broad spectrum)
Polymyxin B is only for topical use. If it is ingested, Polymyxin B can cause what?
numbness in the extremities, kidney damage, respiratory arrest
Sulfonamides are natural, synthetic, or semi-synthetic?
Give one type of sulfonamide
Sulfanilimide is a structural analog of ____
p-aminobenzoic acid (aka PABA)(-SO2NH2 vs. COOH)
Sulfonamides inhibits _____ production by competing with p-aminobenzoic acid for active site of dihydropterate synthase, an enzyme
folic acid
Sulfonamides inhibits folic acid production by competing with _____ for active site of dihydropterate synthase, an enzyme
p-aminobenzoic acid
Sulfonamides inhibits folic acid production by competing with --aminobenzoic acid for active site of _____, an enzyme
dihydropterate synthase
Folic acid is required for ____
nucleic acid production
bacteria make their own ____, but not humans
folic acid
Sulfonamides have a high ____, but about 5% of ppl are allergic
therapeutic index *toxic dose/ therapeutic dosehigher therapeutic index, better chemotherapeutic agent
Give two examples of sulfonamides
What two antibiotics inhibits DNA Synthesis?
Give an example of QUINOLONES, which disrupts prokaryotic DNA gyrase (inhibits DNA Synthesis)
Nalidixic acid
Nalidixic acid selectively inhibits _____, an enzyme required for DNA replication
DNA gyrase
What is Nalidixic acid effective against?
only effective against certain types of urinary infections. *most likely narrow-spectrum
Who is Nalidixic acid bad for? whY?
Bad for kids & pregnant women because it affects development of cartilage
Give two types of fluoroquinolones, which inhibits DNA Synthesis
Fluoroquinolones were developed as improvements over nalidixic acid (an extra F added), because they ____ and ____
penetrate tissue bettermore broad-spectrum (can treat urinary infections + anthrax + others)
What is a drug that inhibits RNA synthesis?
Is Rifampin natural, synthetic, or semi-synthetic?
Rifampin inhibits DNA-dependent ______ in bacteria
RNA polymerase, an enzyme
What three things is Rifampin used for?
TuberculosisLeprosyProtection against bacterial meningitis
Rifampin turns bodily secretions ____
reddish orange
what four things inhibits cell wall synthesis?
What do all penicillins have?
beta-lactam nucleus
Penicillins inhibit transpeptidation (linking of polymers w/ amino acid chains) and consequently _____
cell wall synthesis (results in osmotic lysis)
Penicillins inhibit _______(linking of polymers w/ amino acid chains) and consequently cell wall synthesis (results in osmotic lysis)
What is a semi-synthetic derivate of Penicillin?
What is good about ampicillin compared to penicillin?
more acid stable
What are two problems with penicillins?
allergic reactionsgrowing resistance
If you are allergic to penicillin, then you could take _____
What does Cephalosporins inhibit?
cell wall synthesis
Give two examples of cephalosporins
cephalexin (Keflex)cephalothin (Keflin)
Are cephalosporins natural, synthetic, or semi-synthetic?
Natural, from fungus Cephalosporium
Cephalosporins are a natural antibiotic from the fungus _____
Cephalosporins are similar to penicillin in waht way?
beta-lactam ringsimilar mechanism of action
Cephalosporins have a beta-lactam ring like penicillin, therefore cephalosporins have a similar _____
mechanism of action
Cephalosporins are a useful alternative to penicillin in case of ___ or ___
allergy or resistance
Bacitracin, another cell wall synthesis inhibitor, interferes with ____, a carrier that transports peptidoglycan subunits to the cell wall
Give four antibiotics that inhibit Protein Synthesis.
Tetracyclines are narrow or braod-spectrum?
broad-spectrum (affects Gram - and +)
What makes up tetracyclines?
four benzene rings
Some tetracyclines are natural and are produced from ___
Some tetracyclines are natural and produced from Streptomyces. Give two examples.
Some tetracyclines are semi-synthetic. Give four examples.
Tetracyclines all inhbibit protein synthesis by binding _______
30S ribosomal unit
All inhibit protein synthesis by binding 30S ribosomal unit- inhibits binding of _____ to ____
tRNA to ribosome
Who are tetracyclines bad for? why?
Bad for kids and pregnant women- problems with bone formation (yellow teeth)
Tetracyclines is the drug of choice for _____ and _____ diseases
rickettsial and chlamydial diseases
Aminoglycosides inhibits protien synthesis. They are amino groups bound to ____
glycosides (carbohydrates)
What are glycosides?
What three aminoglycosides comes from Streptomyces?
What aminoglycoside comes from Micromonospora purpurea?
Aminoglycosides prevent reading of ____ by irreversibly binding to ribosome
Aminoglycosides prevent reading of mRNA by _____
irreversibly binding to ribosome
Why are aminoglycosides toxic?
Deafness, renal damage, loss of balance
What are macrolides composed of?
12-22 carbon lactone ring
Are macrolides broad-spectrum or narrow?
broad-spectrum(Gram +/-, mycoplasma)
Give four examples of macrolides
Macrolides inhibit ____
peptide chain elongation(protein synthesis)
Legionnaire's Disease is transmitted by?
airair conditionershumidifiersthe spray of jacuzzi tubs
What are Macrolides used to treat?
Legionnaire's Disease
Chloramphenicol binds ____ and blocks ______ to inhibit protein synthesis
ribosome peptide bond formation
Is Chloramphenicol natural, synthetic, or semi-synthetic?
natural, from Streptomyces
Where is Chloramphenicol produced from?
Is Chloramphenicol narrow or broad-spectrum?
broad-spectrum (bacteria, small bacteria, fungi)
Chloramphenicol has a low ____: used only in life-threatening situations
therapeutic index
Chloramphenicol can cause _____ by preventing hemoglobin from being incorporated into RBC (red blood cell)
aplastic anemia
Besides aplastic anemia, what else can chloramphenicol cause?
gray syndrome
Gray syndrome is a toxic reaction to chloramphenicol. It is the breakdown of the ___
cardiovascular system
What are the two bad side effects of chloramphenicol?
Aplastic anemiaGray syndrome
What are the 6 things that affect bacteria?
cell wallcell membranemetabolism (folic acid)DNA synthesisRNA synthesisprotein synthesis
What are the four mechanisms of resistance?
Modification of targetPrevent entrance of drugprump drug out of cellchemical modification
Modification of target. Resistance to ______ develops when bacteria alter structure of enzymes used to synthesize folic acid
Resistance to _____ develops when bacteria alter structure of ribosomes
Prevent entrance of drug. Mycobacterium has _____ in cell wall
mycolic acid
Mycobacterium has mycolic acid in cell wall. Mycolic acid is _____ to most drugs
Pump drug out of cell. Enzymes such as plasma membrane _____ pumps drugs out of cell.
Pump drug out of cell. Some microbes have ___
multi-drug resistance pumps
Inactivation through Chemical Modification. Penicillinase (beta-lactamase) can effect ______- inactivating antibiotic
hydrolysis of beta-lactam ring
_________ (beta-lactamse) can effect hydrolysis of beta-lactam ring- inactivating antibiotic
Inactivation through Chemical Modification. Penicillinase (Beta-lactamase) can effect hydrolysis of beta-lactam ring- inactiving antibiotic. This type of resistance can be encoded by ____
plasmids. transferred by conjugation and transformation
Give two reasons as to why microbial drug resistance is increasing
indiscriminate use of chemotherapeuticstransmission of R factors among microbes
R factors transferred between _____ through conjugation
unrelated strains
What is indiscriminate use? (3 pts)
Prescription of antibiotics for viral infectionsLow-level use of antibiotics for prevention of infectioninclusion of antibiotics in animal feed
By the process of natural selection, microorganisms that are resistant to a particular drug gradually become ____
predominant in a population
What does PPNG stand for?
penicillinase-producing Neisseria gonorrhoeae*No PPNG strains before 1976
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