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What type of antibiotic is good for bloodstream infections - bacteriostatic or bacteriocidal?
✔Correct Answer-Bacteriocidal
T/F? Penicillin is a broad spectrum antibiotic? ✔Correct Answer-False, it is narrow spectrum
What broad classes of bacteria does penicillin cover? ✔Correct Answer-- Gram +
- Anaerobes
What are the 2 classes of cell wall synthesis inhibitors? ✔Correct Answer-1. Beta-Lactams: these
bind to and blocks transpeptidase (a penicillin binding protein) and prevent formation of the cross-
links in peptidoglycan
2. Glycopeptides: bind to the terminal amino acid of tetrapeptide and blocks transpeptidase from
acting
What does penicillin-binding protein do? ✔Correct Answer-It forms the 1,4 cross links between
NAMS and UMP on the exterior of the bacterial cell for completion of peptidoglycan synthesis
- inhibited by penicillin
What does transpeptidase (a penicillin binding protein) do? ✔Correct Answer-- Forms peptide
cross links between glycan chains to make peptidoglycan layers
T/F? Beta-lactams and glycopeptides are bacteriostatic? ✔Correct Answer-False, they are all
bactericidal
Name the 4 classes of beta-lactams. ✔Correct Answer-1. Penicillin
2. Cephalosporins
3. Carbapenems
4. Monobactams
Describe penicillins. ✔Correct Answer-- Original was only used in gram + bacteria (modifications
now used against both gram + and gram -)
- Penicillins are sensitive to beta-lactamase that is secreted by the bacteria and cause it to be
ineffective
Name the modifications of penicillins. ✔Correct Answer-1. Ampicillin
2. Amoxicillin
3. Methicillin
What are cephalosporins? ✔Correct Answer-- Structure: Beta-Lactam ring attached to a 6-member
ring
- Beta-Lactamase resistant
- Classified according to each generation: each generation corresponds to a modification that
improves absorption and increases spectrum (classes 1-5)
,What generations of Cephalosporins are resistant against both gram - and gram + bacteria?
✔Correct Answer-4 and 5
Describe carbapenems. ✔Correct Answer-- Newly made in the 1990s
- Broadest spectrum
- Resistant to beta lactamase
- Can only be given thru IV in a hospital
- Useful against gram - bacteria that are resistant to many other drugs
Which beta-lactams are resistant to beta-lactamase? ✔Correct Answer-- Methicillin (only 1
derivative of penicillin)
- Cephalosporins
- Carbapenems
- Monobactams
What are the two types of glycopeptide antibiotics available? ✔Correct Answer-- Vancomycin
- Teichoplanin
Describe Vancomycin and Teichoplanin. ✔Correct Answer-- Bind to the terminal amino acid,
alanine, of the tetrapeptide chain and prevent transpeptidase from making cross-links between the
peptidoglycans
- Lipophilic
- Only used against gram + bacteria
- Administered via IV
- Drug of choice for hospital acquired MRSA
(Pneumonic - In the hospital watch a lot of TV which is positive - so the Teichoplanin and
Vancomycins are given for hospital acquired MRSA and useful against gram + only)
What are the 6 types of protein synthesis inhibitors? ✔Correct Answer-1. Aminoglycosides (A)
2. Tetracyclines (T)
3. Erythromycin (E)
4. Chloramphenicol (C)
5. Clindamycin
6. Oxazolidonones
7. Macrolides
ATECCOM
Which, if any, of the protein synthesis inhibitor antibiotics are bactericidal? ✔Correct Answer-
Aminoglycosides
What antibacterial agents are useful against hospital acquired and regular MRSA (separately)?
✔Correct Answer-- Hospital acquired: Vancomycin and Teichoplanin
- Regular MRSA: Oxazolidones
What are the 4 categories of drugs that inhibit nucleic acid synthesis? ✔Correct Answer-1.
Quinolones
2. Folate synthesis
3. Methonidazole
4. Rifampin
Describe the quinolones. ✔Correct Answer-- Bacteriocidal
, - Inhibit DNA gyrase (a topoisomerase 1)
- Broad spectrum, effective against intracellular microbes (viruses)
- Administered orally
- Well tolerated/mild on host
- The examples Ciprofloxacin and Levoquin have a fluorine derivative added for improved absorption
that can cause tendon rupture and peripheral neuropathy
Describe Rifampin. ✔Correct Answer-- Bacteriocidal
- Binds to the beta subunit of RNA polymerase and makes it non functional; so inhibits transcription
and translation
- Use is restricted to treatment of mycobacterium tuberculosis (an opportunistic infection associated
with HIV) or prophylactic for meningities
How do mycobacterium tuberculosis become resistant to Rifampin? ✔Correct Answer-- When
using, mycobacterium replicates VERY slowly, slower than eukaryotic cells, so these drugs must be
given for long time periods (6 months to a year).
- Over time the virus develops resistance, via changing their RNA polymerase. So Rifampin is used in
combination with another drug
Decribe folate inhibitors. ✔Correct Answer-- Bacteriostatic
- Bacteria make folate to make the deoxyribonucleotides for DNA synthesis (humans get folate from
diet, while bacteria make it)
- Folate synthesis pathway is an absolute selective pathway
- Resistance to the sulfonamids became common because it was used so much
Describe sulfonamides. ✔Correct Answer-- Earliest folate synthesis inhibitor
- Is a structural analog of paramino benzoic acid (PABA), so it blocks folate synthesis by binding to
the dihydropteroic acid
- Resistance to the sulfonamides (e.g., Sulfamethoxazole) became so common place that now the
drugs have to be given in combination with Trimethoprim which will block the dihydrofolate
reducatase so that tetrahydrofolate is not made
How are bacteria resistant to sulfonilamides? ✔Correct Answer-- By altering their dihydrofolate
reducatses
- By altering their dihydropteroate synthase
Describe the cell membrane disrupter antimicrobials. ✔Correct Answer-- Called Polymixins
- Highly toxic to the brain and kidney by binding to membranes rich in phosphatidylethanolamine
- Act as a detergent
- Used in 3rd world countries; not used in the US
- Disrupt membrane integrity of bacteria cells and our cells
Describe the mechanism for enzymatic inactivation of beta-lactam antibiotics. ✔Correct Answer--
Penicillin resistance: Penicillin normally binds to transpeptidase and prevents cross-linking
- Some gram + bacteria make beta-lactamase which cleaves the beta lactam ring making the
penicillin inactive; peptide crosslinks occur and bacteria live
What drug is used to inhibit beta-lactamase? ✔Correct Answer-- Clavulanic acid, alone it has
minimal bactericidal activity. Used in combination with other beta lactam antibiotics, the clavulanic
acid acts as a suicide inhibitor.
, - It is cleaved by the beta lactamase and then binds to beta lactamase and makes it inactive, its
cleavage allows the beta lactam antibiotic to remain functional
What are a few indications for penicillin use? ✔Correct Answer-- Steptococcus pyogenes cellulitis,
dental infections, etc.
What are the symptoms of Strep. Pyogenes cellulitis? ✔Correct Answer-Spread of group A
streptococcus pyogenes to the subcutaneous layer of the skin causes a red, painful rash that may be
swollen
T/F? Penicillin inhibits cell wall synthesis? ✔Correct Answer-True
Would you give 2 or more beta-lactams at the same time? ✔Correct Answer-False
Which Penicillin provides coverage for MRSA? ✔Correct Answer-Ceftaroline
T/F? When someone comes into the hospital you would start them on penicillin right away?
✔Correct Answer-False, you don't give penicillin right away because it has too narrow of a spectrum
Why were semisynthetic penicillins developed? ✔Correct Answer-Because penicillins became
inhibited by beta lactamase
What does beta lactamase do? ✔Correct Answer-Enzyme that breaks up the beta lactam ring and
makes penicillin unable to bind to penicillin-binding proteins on bacteria
What was the prototype for semisynthetic penicillins? ✔Correct Answer-Methicillin
List the extended spectrum penicillins. ✔Correct Answer-- Aminopenicillins
- Carboxypenicillins
- Ureidopenicillins
T/F? Extended Spectrum Penicillins are resistant to the penicillanses made by staphylococci?
✔Correct Answer-False, they are NOT resistant to these pencilinases
T/F? Amoxicillin is an IV-administered antibiotic? ✔Correct Answer-False, it is administered orally
T/F? Ampicillin and Amoxicillin both have the same spectrum of bacteria they can treat? ✔Correct
Answer-True
Why do extended-spectrum penicillins have a broader spectrum than penicillin? ✔Correct Answer-
Because they are made to penetrate the cell wall of gram - bacteria and can better bind to pencillin
binding proteins
T/F? Piperacillin is a type of ureidopenicillin? ✔Correct Answer-True
T/F? Ureidopenicillins (like Piperacillin) used alone are effective against Beta-lactamase producing
Staphylococci or H. Influenzae? ✔Correct Answer-False, not effective against these when used by
themselves. have to use in combination.
T/F? Ureidopenicillin is a broad spectrum penicillin? ✔Correct Answer-True