Antibiotics

Question 1

Cell wall synthesis inhibitors

Answer 1

peptidoglycans: beta-lactams and glycopeptides

Question 2

Beta-lactam function

Answer 2

prevent cross-linking of aa’s, cidal

Question 3

Beta-lactam classes

Answer 3

penICILLINS, CEPHalosporins, carbaPENEMs, monobactams (ONAM)

Question 4

Beta-lactam resistance mechanims

Answer 4

alternative target, restriction to access of target site, antibiotic destruction

Question 5

how to avoid antibiotic destruction

Answer 5

antibiotic with protease inhibitor

Question 6

Cephalosporins features

Answer 6

1-3 Gram +, 4-5 Gram -

Question 7

Carbapenems features

Answer 7

wide spectrum of activity, drugs of last resort

Question 8

Beta lactams dont work against…

Answer 8

species without cell wall, very impenetrable walls, intracellular pathogens

Question 9

Glycopeptides features

Answer 9

Gram + only bc its huge and cant get through gram - membrane, binds to actual peptides, bactericidal, ie: Vancomycin, teicoplanin

Question 10

Components of vancomycin resistance

Answer 10

Encoded on plasmid, alter peptide target (key), lock and key mechanism no longer works, blocks crosslinking

Question 11

Common cell membrane disruptors

Answer 11

Daptomycin, colistin (polymyxin B)

Question 12

Features of daptomycin

Answer 12

cyclic lipoprotein, inserts into membrane causing lysis, gram + only (used against vanco–resistant), bacteriacidal, resistance: efflux, membrane alterations, modify cell membrane charge

Question 13

Colistin, polymoxin B features

Answer 13

gram (-) only, binds to LPS, cell lysis, bactericidal, kept as “last line of defense”, rare resistance with LPS mods

Question 14

Which types inhibit nucleic acid synthesis

Answer 14

sulfonamides, trimethoprim, fluoroquinolones, rifamycins

Question 15

Sulphonamides features (DNA base synthesis)

Answer 15

sulfonamides: dihydroptefoate synthase inhibition, trimethoprim: dihydrofolate reductase inhibtion; often given together, bacteriostatic, resistance: efflux, point mutations, alternative enzymes

Question 16

Fluoroquinolones features

Answer 16

broad spectrum (aerobic gram +/-); -FLOXACIN; inhibits bacterial DNA gyrase and topoisomerase, bactericidal, resistance: point mutations, cell wall permeability, efflux pumps

Question 17

RNA synthesis inhibtor

Answer 17

RIFamycins = RNA synthesis; RIFampin

Question 18

RIFampin features

Answer 18

Binds to DNA dependent RNA polymerase, blocks mRNA synthesis, bactericidal, resistance: very eary, mutations to alter RNA polymerase target

Question 19

Protein synthesis inhibitors

Answer 19

50S: Chloramphenicol, macrolides (-mycin), lincosamides (-mycin), oxazoladinones (-zolid, cidal)

30S: aminoglycosides, tetracyclines

Question 20

30S subunit antibiotic features

Answer 20

Aminoglycosides: -MICIN, -MYCIN, inhibit initiation complex, bactericidal, aerobic gram (-) rods
TetraCYCLINEs: doxyCYCLINE, blocks tRNA from acceptor site, bacteriostatic, gram +/-

Question 21

what are nitroimidazoles

Answer 21

antibiotic that causes DNA breaks, anaeobic and some protozoans, bactericidal

Question 22

50S subunit antibiotic features

Answer 22

Chloramphenicol: prevent elongation, gram +/-, aerobes anaerobes, intracellular; bacteriostatic: resistance: acetyltransferase

Macrolides: erythroMYCIN, azithromycin; interferes with elongation; gram + cocci, especially strep, bacteriostatic

Lincosamides: clindamycin, interferes with elongation, more active against anaerobes, poor penetration, bacteriostatic

Oxazolidinones: lindeZOLID, interferes with intiation of protein translation, cidal

Question 23

what are oxazolidinones

Answer 23

lineZOLID, tedZOLID; binds to ribosome prevents formation of initiation complex, used against drug-resistant gram + cocci (MRSA), can be bactericidal/static,

Question 24

what is nitrofurantoin

Answer 24

antibiotic that is converted by bacterial enzymes to electrophilic intermediates which inhibits many processes, gram -/+; bacteriostatic; resistance is almost impossible

Question 25

What is prophylaxis

Answer 25

antimicrobial agents used to prevent infection