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39 Cards in this Set

  • Front
  • Back
antibiotics that prevent the synthesis of intact peptidoglycan are called:
bactericidal
Vancomycin prevents insertion of the ... into the .... by binding to ...
peptidoglycan chain
cell wall
D-ala-D-ala
Bacitracin is a peptide antibiotic that interferes with the formation of ...
bactoprenol phosphate
Cycloserine has a structure that is very similar to ... and it inhibits ...
D-ala
the enzymes that make D-ala-D-ala
Fosfomycin prevents the synthesis of ...
UDP-N-acetylmuramic acid
... and ... both inhibit mycolic acid synthesis and are bactericidal against ...
Isoniazid
ethionamide
mycobacteria
what are the antibiotics that inhibit protein synthesis:
1.
2.
3.
4.
5.
6.
7.
1. Aminoglycosides
2. Tetracyclines
3. Oxazolidinones
4. Chloramphenicol
5. Macrolides
6. Lincosamides
7. Streptogramins
... is active against 70s and 80s ribosomes and requires ... to get into cell. Eukaryotic cells do not accumulate this antibiotic and therefore are not killed by it. these antibiotics are ... (mechanism of action)
tetracycline
active transport mechanism
bacteriostatic
Streptogramin antibiotics are a mixture of ..., called group A ... and group B ... the two peptides act synergistically to prevent protein synthesis by ...
two different cyclic peptides
streptogramins
streptogramins
preventing peptide bond formation
what are the antibiotics that inhibit DNA structure:
1.
2.
1. Quinolones, and the newer versions, fluoroquinolones
2. Metronidazole
what is the mode of action for the antibiotics quinolones and fluoroquinolones act:
inhibit the enzymes which supercoil the DNA
what is the mode of action for the antibiotic metronidazole:
bacteria reduce a nitro group on metronidazole that make the antibiotic highly toxic that disrupts DNA
... forms a stable complex with RNA polymerase and prevents chain initiation.
Rifampin (aka rifampicin)
there is a group of cyclic polypeptides called ..., which interfere with the ... portion of the outer membrane, causing cell death. these antibiotics are usually administered ... and are effective against ... bacteria.
polymyxins
Lipid A
topically
Gram-negative
what antibiotics inhibit bacterial metabolism and how:
1.
2.
1. Sulfonamides prevent folic acid synthesis
2. Trimethoprim inhibits the enzyme, dihydrofolate reductase, which is required to convert folic acid to the active form, tetrahydrofolate
... and ... act synergistically, and are usually prescribed together
Sulfonamides
trimethoprim
tetrahydrofolate is required for thymidine biosynthesis therefore the antibiotic ... prevents DNA synthesis
trimethoprim
what are the major mechanisms for resistance:
1.
2.
3.
1. destruction of antibiotic
2. preventing antibiotic from reaching critical concentration within bacterial cell
3. alteration of target site
what is an example of destruction of antibiotic:
breaking down of β-lactam ring
The β-lactamases have different activity spectra. Some are active only against ... and some are active against all the different classes of ...
penicillins (penicillinases)
β-lactamases
Aminoglycosides can be destroyed by enzymes that add ... or ... or even add an entire ... molecule to the antibiotic. Once these groups are added to the antibiotic, it is no longer able to bind to the ... ribosomal subunit and prevent protein synthesis
phosphate
acetyl groups
AMP
30s
how can bacteria cells prevent antibiotic from reaching a critical concentration within the bacterial cell:
1.
2.
1. alter porins size
2. pump the antibiotic out of the cell
One mechanism by which bacteria can become resistant to β-lactam antibiotics is by altering the ... so that the antibiotic can no longer bind to them.

what organism uses that mechanism:
penecillin bind proteins
Staphylococcus aureus uses for methicillin resistance
Some bacteria can alter their ... so that vancomycin no longer prevents cross-linking
peptidoglycan
By altering the ... ribosomal subunit, bacteria can become resistant to both streptogramins and macrolides
50s
the antibiotics streptogramins and macrolides target the ... in bacteria
50s ribosomal subunit
Resistance to β-lactam antibiotics is mediated by two different mechanisms:
1.
2.
1. β-lactamase
2. production of a second PBP
what 2 genes make MRSA strains resistance to all β-lactam antibiotics:
1.
2.
1. mecA
2. blaZ
clustering virulence genes in ... helps in spreading virulence from strain to strain.
pathogenicity islands
Some MRSA strains have become resistant to vancomycin. The gene which provides vancomycin resistance is called ... and is carried on a transposon (Tn1546). The transposon is transferred from one strain to another via ...

It is likely that this transposon was transferred to Staphylococcus aureus from ...
vanA
plasmid
Enterococcus faecalis
Aminoglycoside resistance is due to ... of the antibiotics
inactivation
Staphylococcus aureus makes ... which removes tetracyclines from the cell.
an efflux pump
Chloramphenicol resistance is due to ... of the antibiotic by the product of the ... gene
acetylation
cat
Resistance to macrolides and lincosamides is due to ... of the ... found in the 50s ribosomal subunit
methylation
23s rRNA
Resistant to the streptogramins is due to ... of the streptogramin A component and ... of the streptogramin B component
efflux
inactivation
what are the two mechanisms that have evolved in Staphylococcus aureus to provide resistance to the fluoroquinolones:
1.
2.
1. efflux pump
2. change in topoisomerase
Resistance to rifampicin is due to chromosomal mutations in the ...
β-subunit of RNA polymerase
Resistance to trimethoprim is due to production of a second ... which is not inhibited by trimethoprim
dihydrofolate reductase
Resistance to sulfonamides is due to a chromosomal mutation which increases production of ... which overcomes the competitive inhibition of the enzyme in ...
p-aminobenzoic acid
folic acid synthesis