Bugs & Drugs

Question 1

hemolytic anemia associated with G6PD deficiency can present with _______

Answer 1

fatigue and scleral icterus (yellow in eyes) with elevated lactate dehydrogenase and total bilirubin

Question 2

patients with G6PD deficiency are susceptible to developing ____ when they are exposed to ____ drugs

Answer 2

hemolysis when they are exposed to oxidizing agents such as sulfonamides like sulfamethoxazole

Question 3

trimethoprim and pyrimethamine mechanism

Answer 3

inhibits dihydrofolate reductase (folate synthesis need for DNA)

Question 4

sulfonamides and dapsone mechanism

Answer 4

inhibits dihydropteroate synthase (folate synthesis needed for DNA)

Question 5

aminoglycosides are commonly associated with what side effects?

Answer 5

ototoxicity (high frequency hearing loss) and nephrotoxicity

Question 6

tetracyclines toxicity includes:

Answer 6

tooth discoloration, photosensitivity reactions and inhibition of bone growth in children

Question 7

flouroquinolone toxicity includes:

Answer 7

achilles tendonitis

Question 8

macrolides toxicity includes:

Answer 8

acute cholestatic hepatitis, eosinophilia and skin rashes

Question 9

what are the aminoglycosides?

Answer 9

30s ribosomal subunit against gram negative rod infections. Cannot treat anaerobes bc requires O2 for uptake
“GNATS”
gentamicin, neomycin, amikacin, tobramycin, streptomycin

Question 10

when combined with alcohol, ____ causes a disulfiram-like “hangover” reaction

Answer 10

metronidazole
buildup of acetylaldehyde

Question 10

what are the fluoroquinolones?

Answer 10

end in “floxacin”
inhibit topo 2 (DNA gyrase)
bactericidal
against gram negative rods of urinary and GI tracts (including pseudomonas)

Question 10

symptoms and treatment of trichomonas vaginitis

Answer 10

frothy, yellow-green foul smelling discharge. pear shaped trichomonads
metronidazole

Question 10

symptoms and treatment of candida vulvovaginitis

Answer 10

thick, white, “cottage cheese” discharge.
pseudohyphae
treat with azoles

Question 11

how does metronidazole work?

Answer 11

forms toxic free radical metabolites in the bacterial cell that damage DNA
bactericidal and antiprotozoal

Question 12

what is the mechanism of resistance to aminoglycosides?

Answer 12

inactivation via enzymatic modification like acetylation, phosphorylation, adenylation etc.

Question 13

what is the mechanism of resistance for vancomycin?

Answer 13

amino acid modification of D-Ala-D-Ala to D-Ala-D-Lac

Question 14

what is the mechanism of resistance for penicillins?

Answer 14

structural change in transpeptidases (PBPs = penicillin binding proteins)

Question 15

what is the mechanism of resistance against macrolides?

Answer 15

methylation of 23S rRNA-binding site to prevent the drug from binding

Question 16

what are the penicillinase-resistant penicillins?

Answer 16

dicloxacillin, nafcillin, oxacillin

use “Naf” for staph! (except MRSA)

Question 17

what is the mechanism for penicillinase-resistant penicillins?

Answer 17

similar to penicillin but has a narrow spectrum. Penicillinase resistant because bulky R groups block access of beta-lactamase to beta-lactam ring

Question 18

aspergillus fumigatus

Answer 18

branching of septate hyphae, catalase positive
immunocompromised patients can get aspergillomas after TB infection
treat with voriconazole or echinocandins (2nd line)

Question 19

cryptococcus neoformans

Answer 19

narrow budding, heavily encapsulated yeast. can see clear halo with india ink
found in soil and pigeon droppings

Question 20

sores on penis can indicate ____

Answer 20

syphillis, confirm diagnosis with flourescent treponemal antibody test. treat with penicillin G

Question 21

how do macrolides work?

Answer 21

inhibits protein synthesis by blocking translocation

Question 22

how do cephalosporins work?

Answer 22

beta lactam drugs that inhibit cell wall synthesis but are less susceptible to penicillinases

Question 23

what type of infection does ciprofloxacin treat?

Answer 23

aerobic gram-negative rod infections

Question 24

what drug can cause "red man syndrome" and is also often used to treat MRSA?

Answer 24

vancomycin

Question 25

what categories of bacteria does clindamycin treat?

Answer 25

anaerobes and gram positive organisms, good for treating pulmonary abscess

Question 26

what is the first line treatment of UTIs in pregnant women?

Answer 26

nitrofurantoin, it damages bacterial DNA and ribosomal proteins after intracellular reduction into reactive molecules

Question 27

what is the mechanism of resistance for macrolides?

Answer 27

methylation of rRNA at a ribosome-binding site

Question 28

what type of bacteria is C. Diff?

Answer 28

gram positive, anaerobic, spore former

Question 29

what is the treatment for clostridium profringes?

Answer 29

clindamycin

Question 30

what is bacitracin active against?

Answer 30

gram positive staph and strep

Question 31

chlamydia has what type of discharge?

Answer 31

watery

Question 32

gonorrhoeae has what type of discharge

Answer 32

thick, can be green-yellowish or white

Question 33

what is the treatment for chlamydia?

Answer 33

azithromycin (macrolide) or doxycycline (tetracycline)

Question 34

what is the treatment for gonorrhoeae?

Answer 34

cephtriaxone (cephalosporin)

Question 35

what penicillins are beta lactamase resistance?

Answer 35

nafcillin and oxacillin have a bulky R side chain that blocks beta lactamases from beta lactam ring

Question 36

what drug works synergistically with beta lactams?

Answer 36

aminoglycosides (concentration dependent)

Question 37

what is the drug of choice for staph aureus? (not MRSA)

Answer 37

nafcillin

Question 38

what are the anti pseudomonal penicillins?

Answer 38

piperacillin and ticarcillin

Question 39

what fungal disease presents as annular plaques?

Answer 39

tinea corporis "ringworm"

Question 40

what is used to treat systemic ringworm?

Answer 40

itraconazole, blocks the formation of fungal membrane sterols by inhibiting fungal cytochrome P-450

Question 41

what antifungal is used for chronic suppression of cryptococcal meningitis in people with HIV?

Answer 41

fluconazole

Question 42

how does MRSA resist beta lactams?

Answer 42

by altering its penicillin binding protein

Question 42

treatment for leishmania donovani

Answer 42

atovaquone and azythromycin

Question 43

what parasite presents with bloody stool?

Answer 43

entamoeba hystolytica

Question 44

what parasite presents with swollen eye?

Answer 44

trypanososma cruzi (chagas disease caused by kissing bug)

Question 45

what is the treatment for complicated malaria?

Answer 45

quinine

Question 46

what is the treatment for uncomplicated malaria?

Answer 46

chloroquine, second choice primaquine but can cause cardiac arrhythmia

Question 47

what are the prophylactics for malaria?

Answer 47

atovaquone (inhibits ETC) proguanil (inhibits DHFR)

Question 48

what parasite presents with maltese cross in blood smear?

Answer 48

babesa (tick bite in northeast)

Question 49

what kind of virus is HIV?

Answer 49

retrovirus (+ ssRNA)

Question 50

what enzyme do retroviruses (+ssRNA) use?

Answer 50

reverse transcriptase

Question 51

all DNA viruses except poxvirus replicate in the ____

Answer 51

host cell nucleus

Question 52

all RNA viruses except influenza replicate in the ____

Answer 52

cytoplasm

Question 53

DNA viruses use what machinery to replicate?

Answer 53

enters the nucleus and uses host cell nucleic acid synthesis machinery

Question 54

RNA viruses use what machinery to replicate?

Answer 54

since they replicate in the cytoplasn, they use their own machinery in combo with host cell ribosomes +ssRNA can be directly translated by host ribosomes -ssRNA brings RNA-dependent RNA polymerase to switch to +ssRNA

Question 55

what are some DNA viruses?

Answer 55

herpesvirus & pox virus (enveloped), papillomavirus (naked)

Question 56

what does the diptheria exotoxin do

Answer 56

ribosylates EF-2, inhibiting protein synthesis

Question 57

what does the cholera exotoxin do

Answer 57

ribosylates GTP binding protein, increasing cAMP = fluid loss as seen in rice water stools