Usmle Antibiotics And Resistance 1

Front 1

most common mechanism of R in Enterococcus?

Back 1

chromosome-mediated alteration of ribosome function

Front 2

chromosome mediated decrease uptake thru outer membrane is major mechanism of drug R for?

Back 2

Pseudomonas, anaerobes

Front 3

mech of drug R most often expressed agaisnt tetracyclines and sulfonamides?

Back 3

plasmid-mediated exportation

Front 4

mech by which linear pieces of exogenous DNA incorporated into bacterial chromosome using RecA?

Back 4

homologous recombination

Front 5

mech by which temperate phage can accidentally transfer genetic material from 1 bacterium to another, following error or excision?

Back 5

specialized transduction

Front 6

mechanism by which lytic phage can accidentally transfr genetic material from 1 bacterium to another?

Back 6

generalized transduction

Front 7

resistance to pyrazinamide due to?

Back 7

(inhibits fatty acide synthetase); mutaitons in gene that encodes amidase--responsible for converting PZA to active form

Front 8

resistance to ethambutol due to?

Back 8

(inhibits synthesis of arabinogalactin); mutations in gene that encodes arabinosyl transferase. this enzyme synthesizes arabinoglactin in TB cell wall

Front 9

resistance to isoniazid due to?

Back 9

(inhibits mycolic acid synthesis); mutations in catalase-peroxidase gene--required for synthesis of active metabolite

Front 10

resistance to quinolones due to?

Back 10

(inhibit DNA gyrase); chromosomal mutations-->modify DNA gyrase OR change in bacteria outer membrane proteins-->reduced uptake

Front 11

resistance to rifampin due to?

Back 11

(blocks RNA polymerase); chromosomal mutaiton in gene for beta subunit of bact.RNA polymerase

Front 12

resistance to trimethoprim due to?

Back 12

(inhibit DHFR); mutations in csomal gene encoding DHFR

Front 13

resistance to sulfonamides due to?

Back 13

(PABA analog, inhibits synth of THF); 1) R factor--encodes transport system that actively exports drug; 2) csomal mutation--reduces binding affinity for dihydropteroate synthetase

Front 14

resistance to erythromycin due to?

Back 14

(macrolide, binds 50S, blocks translocation); R factor--enzyme methylates 23S rRNA thereby blocking binding of drug

Front 15

resitance to cholamphenicol due to?

Back 15

(binds 50S, blocks axn of peptidyltransferase); R factor--acetyltransferase acetylates and inactivates drug

Front 16

resitance to tetracyclines due to?

Back 16

(bind 30S, block tRNA from entering acceptor site); R factor--dec'd uptake or inc'd export out

Front 17

resistance to aminoglycosides due to?

Back 17

(bind 30S, inhibit initiation complex, misread mRNA); 1) R factor--phosphorylation, acetylation, adenylylation; 2) csomal mutations; 3) dec'd permeability to drug

Front 18

resistance to vancomycin due to?

Back 18

D-ala-D-ala --> D-ala-D-lactate. VanA locus on plasmid transposon

Front 19

6 bacteriCIDal abx

Back 19

penicillin, cephalosporins, vancomycin, aminoglycosides, fluoroquinolones, metronidazole

Front 20

1st gen cephalosporins--names and activity

Back 20

cefazolin, cephalexin; G+ cocci, Proteus, E.coli, Klebsiella

Front 21

2nd gen cephalosporins--names and activity

Back 21

cefoxitin, cefaclor, cefuroxime; G+cocci, H.flu, Enterobacter, Neisseria, Proteus, E.coli, Klebsiella, Serratia

Front 22

3rd gen cephalosporins--names and activity

Back 22

ceftriaxone, cefotaxime, ceftazidime; cross BBB!!

Front 23

4th gen cephalosporins--names and activity

Back 23

cefepime, cefpiramide; increased pseudomonas and G+ activity

Front 24

why use aztreonam?

Back 24

for pen-allergics or renal pts who can't tolerate aminoglycosides

Front 25

drug of choice for enterobacter

Back 25

imipenem w/cilastatin

Front 26

vancomycin toxicity

Back 26

nephrotoxicity, ototoxicity, thrombophlebitis, diffuse flushing (red man syndrome)

Front 27

aminoglycosides--which toxicities enhanced by which drugs?

Back 27

nephrotoxicity--cephalosporin; ototoxicity--loop diuretics

Front 28

which tetracycline ok with renal pts?

Back 28

doxycycline

Front 29

which abx should not be given to COPD pts (on theophylline)?

Back 29

macrolides b/c increase sr [theophylline] (also oral coag)

Front 30

which abx may cause kernicterus in infants?

Back 30

sulfonamides

Front 31

toxicities of trimethoprim

Back 31

megaloblastic anemia, leukopenia, granulocytosis

Front 32

toxicities of polymyxins

Back 32

neurotoxic, acute renal tubular necrosis

Front 33

IFN alpha clinical use?

Back 33

chronic hep B and C, Kaposi sarcoma

Front 34

IFN gamma clinical use?

Back 34

NADPH oxidase def

Front 35

IFN beta clinical use?

Back 35

MS

Front 36

9 abx to avoid in preggers

Back 36

(SAFE Moms Take Really Good Care); sulfonamides (kernicterus); aminoglycosides (ototoxicity); fluoroquinolones; erythromycin; metronidazole; tetracyclines ; ribavarin; griseofulvin; chloramphenicol