micro3

Question 1

fluoroquinolones

Answer 1

ciproflaxin, forfloxacin, levofloxacin, ofloxacin, moxifloxacin, gemifloxacin, enoxacin

Question 2

mechanism of fluoroquinolones

Answer 2

inhibit prokaryotic enzymes topoisomerase II (DNA gyrase) and toposisomerase IV. Bactericidal. must not be taken w antacids

Question 3

use of fluoroquinolones

Answer 3

gram - rods of urinary and GI tracts (including pseudomonas), some gram + organisms, otitiis externa

Question 4

SE of fluoroquinolones

Answer 4

GI upset, superinfectiosn, skin rashes, headache, dizziness;
less commonly, can cause leg cramps and myalgias
prolong QT
tendonitis or tendon reupture in people > 60 yo and in pt’s taking prednisone. ciprofloxacin inhibits cytochrome p450

Question 5

contranidnicsatsion for fluoroquinolones

Answer 5

pregnant women, nursing motehrs, and children <18 yo due to possible damage to cartialge.

Question 6

resistance in fluoroquinolones

Answer 6

chromosome encoded mutation in DNA gyrase; plasmid mediated resistance; efflux pumps

Question 7

daptomycin mechanism

Answer 7

lipopeptide that disrupts cell membranes of gram + cocci by creating transmembrane channels
cannot permeate outer membrane of gram - bcteria = ineffectiev

Question 8

use of daptomycin

Answer 8

S. aureus skin infections (esp MRSA), bacteremia, endocarditis, VRE

Question 9

not used for pneunomia bc avidly binds to and is ianctivated by surfactant

Answer 9

daptomycin

Question 10

SE of daptomycin

Answer 10

myopathy, rhabdomyolysis

Question 11

metronidazole

Answer 11

forms toxic free radical metabolites in bacterial cell that damage DNA. bactericidal, antiprotozoal

Question 12

Use of metronidazole

Answer 12

treats Giardia, entamoeba, trichomonas, gardnerella vaginalis, anaerobes (bacterioides, C. difficile)
can be used in place of amoxiclilin in H. pylori thripple therapy in case of penicillin allergy
GET GAP on the Metro with metronidazole

Question 13

SE of metronidzole

Answer 13

disulfiram like reaction (severe flushing, tachycardia, hypotension) with alcohol, headache, metallic taste
inhibits acetaldehyde hedhyraogenase

Question 14

prophylaxis for m. tuberculosis

Answer 14

isoniazid

Question 15

treatmetn of TB

Answer 15

Rifampin, isoniazid, pyrazinamide, ethambutol (RIPE) for treatment

Question 16

M. avium - intracellulare prophylaxis

Answer 16

azithromycin, rifabutin

Question 17

treatment of M. avium - intracellulare

Answer 17

more drug resistant than M. tuberculosis
azitrhomcyin or clarithromycin + ethambutol
can add rifabutin or ciproflaxin

Question 18

M. leprae prophylaxis

Answer 18

n.a.
long term treatmtn with dapsone and rifampin for tuberculoid form
add clofazimine for lepromatous form

Question 19

Rifamycins

Answer 19

rifampin, rifabutin

Question 20

rifampin mechanism:

Answer 20

inhibit dna dependent rna polymerase

Question 21

use of rifampin

Answer 21

mycobacterium tuberculosis; delay resistance to dapsone when used for leprosy.

Question 22

used for post exposure prophylaxis for meningococcal

Answer 22

rifampin

Question 23

chemoprophylaxis in contacts of children with H. influenzae type B

Answer 23

rifampin

Question 24

SE of rifampin

Answer 24

minor hepatoxicity with drug interactiosn (cytochrome p450; oragne body fluids (nonhazardous side effect)
rifabutin favored over rifampin in pt’s w HIV infection due to less cytochrome p450 stimulation

Question 25

rifampin 4R's

Answer 25

RNA polymerase inihbitor ramps up microsomal cytochrome p450 Red/orange body fluids Rapid resistance if used alone

Question 26

why is rifabutin favored over rinfampin in pt's with HIV infection

Answer 26

due to less cytochrome p450 stimulation

Question 27

mechanisms of resistance to rifampin

Answer 27

mutations reduce drug binding to RNA polymerase. monotherapy rapidly leads to resistance

Question 28

Isoniazid mechanism

Answer 28

decrease syntehsis of mycolic acids; | bacterial catalase peroxidase (encoded by KatG) needed to convert INH to active metabolite

Question 29

use of isoniazid

Answer 29

mycobacterium tuberculosis; the only agent used as solo prophylaxis against TB. also used as monotherpay for latent TB

Question 30

different INH half lives in fast vs slow acetylators

Answer 30

true

Question 31

what forms long branched chain FA's in outer portion of mycobbacterial peptidoglycan cell wall

Answer 31

mycolic acids

Question 32

SE of isoniazid

Answer 32

``` hepatotoxcity p450 inhibition drug induced SLE anion gap metabolic acidosis vitamin B6 deficiency (peripheral neuropathy), sideroblastic anemia) ```

Question 33

INH Injures Neurons and Hepatocytes

Answer 33

hepatoxicity, vit b6 deficiency

Question 34

administer what with isoniazid

Answer 34

b6; inh is strucutarlly similar to b6 ; thus this antibiotic increase urinary excretion of pyridoxine causing deficiency of vit B6 and competes for Vit B6 leading to defective syntehsis of neurotransmitters like GABA

Question 35

resistance to isioniazid

Answer 35

mutations leading to expression of KatG occurs by 2 selective gene mutaionts 1. decrease in bacterial expression of catalase peroxidase enzyme required for isoniaizd activation once drug enters bacterial cell 2. modfiication of protein target bidnign for isoniaizd

Question 36

pyrazinamide mechanism

Answer 36

mechanism uncertain; pyrazinamide is a produgr that converted to active compound pyrazinoic acid works best at acidic pH (in host phagolysosomes)

Question 37

use of pyrazinamide

Answer 37

mycobacterium tuberculosis

Question 38

SE of pyrazinamide

Answer 38

hyperuricemia, hepatotoxcity

Question 39

ethambutol mechanism

Answer 39

decrease carbohydrate polyemraization of mycobacterium cell wall by blocking arabinosyltransferase

Question 40

SE of ethambutol

Answer 40

``` optic neuropathy (red green color blindness) pronounce eyethambutol ```

Question 41

ressitance of ethambutol

Answer 41

increase acitivty of enzymes (arabisonyl transferase) invovled in cell wall by blocking arabinosyltransferase

Question 42

Streptomycin mechanism

Answer 42

inteferes with 30S components of ribosome

Question 43

use of streptomycin

Answer 43

mycobacterium tuberculosis (2nd line)

Question 44

SE of streptomycin

Answer 44

tinnitus, vertigo, ataxia, nephrotoxciicty

Question 45

high risk for endocarditis and undergoing surgical or dental procedures

Answer 45

amoxicilin

Question 46

exposure to gonnorrhea

Answer 46

ceftriaxon

Question 47

history of recurrent UTI

Answer 47

tmp-smx

Question 48

exposure to meningococal infection

Answer 48

ceftriaxone, ciproflaxin, or rifampin

Question 49

pregnant women carrying group B strep

Answer 49

intrapartum penicillin G or ampicillin

Question 50

prevention of gonococcal conjunctivitis in newborn

Answer 50

erythromycin ointment on eyes

Question 51

prevention of post surgical infection due to s. aureus

Answer 51

cefazolin

Question 52

prophylaxis of strep pharyngitis in child with prior rheumatic fever

Answer 52

benzathine penicillin G or oral penicillin V

Question 53

exposure to syphilis

Answer 53

benzathine penicllin G

Question 54

Cd4 <200 HIV in fection: pjp

Answer 54

tmp-smx

Question 55

cd4 <100 pjp, toxoplasmosis

Answer 55

tmp-smx

Question 56

cd4 <50 cells/mm mycobacterium avium complex

Answer 56

azitrhomycin or clarithromycin

Question 57

MRSA treamten

Answer 57

vancomycin, daptomycin, linezolid, tigecycline, ceftaroline, doxycycline

Question 58

VRE treatment

Answer 58

linezolid, streptogramins (quinupristin, dalfopristin)

Question 59

multidrug resistant P. aeruginosa, multidrug resistant Acinetobacter baumannii:

Answer 59

polymyxins B and E (colistin)