AST

Question 1

beta lactams antimicrobial groups

Answer 1

penicillin
cephalosporins
carbapenems
monobactems

Question 2

beta lactams mechanism of action

Answer 2

affect cell wall synthesis

Question 3

penicillin

Answer 3

very narrow spectrum of activity
most Enterobacteriaceae and Staph are resistant

Question 4

beta lactamase inhibitors

Answer 4

combined with beta lactams and help prevent the beta lactamases activity of bacteria

Question 5

cephalosporins

Answer 5

addition of methyl group to beta lactam ring
1st-5th generation and the later generations have broader range of activity
3rd have greater activity against GNR and greater resistance to beta lactamases

Question 6

carbapenems

Answer 6

ertapenem, imipenem, meropenem and doripenem
largely resistant to beta lactamases; widest spectrum of activity
IV

Question 7

monobactems

Answer 7

aztreonam
treats PSA and other GNR

Question 8

glycopeptide antimicrobial group

Answer 8

IV
interferes w/ cell wall synthesis
vancomycin: very large cannot penetrate GN cell wall; used for methicillin resistant organisms (MRSA)

Question 9

antibiotics affecting protein synthesis

Answer 9

aminoglycosides
tetracyclines
macrolides

Question 10

aminoglycosides

Answer 10

bactericidal
bind to 30s ribo preventing attachment to mRNA and translation
treat GN of ab and urinary

Question 11

aminoglycosides examples

Answer 11

gentamycin
tobramycin
amikacin

Question 12

aminoglycoside side effects

Answer 12

nephrotoxicity
irreversible ototoxicity (ears)

Question 13

tetracyclines

Answer 13

bacteriostatic
inhibit by binding 30s ribo and inhibit attach. of tRNA
plasmid mediated resistance is common

Question 14

tetracycline examples

Answer 14

tetracycline
doxycycline
minocycline

Question 15

tetracycline treats what bacteria?

Answer 15

Strep
GNB
rickettsiae
mycoplasma
chlamydia

Question 16

macrolides

Answer 16

bacteriostatic
inhibit prot. syn. by binding 50s ribo inhibit transfer of growing peptide to aa chain
transpeptidation and protein syn. r shut down

Question 17

macrolide examples

Answer 17

erythromycin
azithromycin
clarithromycin

Question 18

macrolides are used to treat what bacteria?

Answer 18

staph
strep
some GN
spirochetes
mycoplasma
chlamydia
drug of choice for bordatella pertusis, mycoplasma, legionella

Question 19

antibiotics affecting nucleic acid synthesis

Answer 19

quinolones
rifamycins

Question 20

quinolones

Answer 20

bacteriocidal
act on DNA gyrase/ topoisomerases to interfere w/ replication

Question 21

quinolone examples

Answer 21

ciprofloxacin
levofloxacin
ofloxacin
moxifloxacin
gemifloxacin

Question 22

quinolones treat what bacteria?

Answer 22

GN (Enteriobacteriacea, Haemophilus, Neisseria, Moraxella catarrhalis

Question 23

quinolone problems

Answer 23

GI disorder may occur
resistance has been seen

Question 24

rifamycins

Answer 24

inhibits RNA polymerase which forms mRNA
rifampin (semisynthetic)
for TB

Question 25

antibiotics affecting metabolic processes

Answer 25

sulfonamides

Question 26

sulfonamides

Answer 26

folic acid syn. inhibitor bacteriostatic used w/ trimethoprim can cause allergic rxn

Question 27

mechanisms of resistance

Answer 27

natural (intrinsic) acquired (mutational) biofilms

Question 28

all strains of Klebsiella are naturally resistant to what antimicrobial?

Answer 28

ampicillin due to gene for penicillin specific beta lactamase

Question 29

anaerobes are intrinsically resistant to what antibiotic?

Answer 29

aminoglycosides due to lack of oxidative ET sys.

Question 30

Staphylococcus saprophyticus is resistant to what antimicrobial?

Answer 30

novobiocin used for ID

Question 31

mechanisms of acquired resistance

Answer 31

`chromo mutations: (target site modification, reduced permeability, bypass inhibited metabolic pathways, activation of efflux systems, prod. of enzymes that modify antibiotic, any combo of above)

Question 32

bacterial biofilms

Answer 32

prevent phagocytosis creates environment for exchange of genetic material

Question 33

MRSA

Answer 33

mecA gene resistant to all beta lactams, cephalosporins, carbapenems

Question 34

what is the drug of choice for MRSA?

Answer 34

VANCOMYCIN

Question 35

what drug is used to test for MRSA?

Answer 35

oxacillin or cefoxitin

Question 36

erythromycin resistance is through what gene?

Answer 36

erm gene

Question 37

D test

Answer 37

erythromycin resistance can trigger clindamycin resistance tests for this Mueller Hinton agar erthyromycin disk and clindamycin disk set close together, if zone of inhibition is a D shape shows inducible clindamycin resistance

Question 38

VRE

Answer 38

vancomycin resistant Enterococcus most common vanA and vanB

Question 39

common antibacterials for UTI

Answer 39

ampicillin cephalothin cefazolin nitrofurantoin ciprofloxacin trimethoprim/sulfamethoxazole gentamicin

Question 40

treatment of Enterococci

Answer 40

ampicillin amoxicillin

Question 41

Enterobacter are intrinsically resistant to what drugs?

Answer 41

ampicillin 1,2, cephalosporins due to ampC beta lactamase

Question 42

Serratia are resistant to what drugs?

Answer 42

ampicillin 1 cephalosporins due to ampC beta lactamase

Question 43

Citrobacter freundii is resistant to what drugs?

Answer 43

ampicillin 1 cephalosporins due to ampC beta lactamase

Question 44

Proteus is resistant to what drugs?

Answer 44

tetracycline and nitrofurantoin

Question 45

Can instruments detect ampC?

Answer 45

no

Question 46

Can instruments detect ESBLs?

Answer 46

Only in E. coli and Klebsiella

Question 47

ESBLs

Answer 47

extended spectrum beta lactamases inactivate penicillins, cephalosporins do not hydrolyze cephamycin AB inhibited by beta lactamase inhibitors inactive against carbapenems

Question 48

keyhole phenomenon

Answer 48

test for ESBL test cefotaxime and ceftazidime alone and w/ clavulanate If zone size increases 5mm or more w/ clavulanate= ESBL+ when disks are placed close together zones looks like a keyhole

Question 49

ampC beta lactamases

Answer 49

are cephalosporinases resistant to beta lactamase inhibitors hyrdolyze cefamycins

Question 50

ampC is found in what organisms?

Answer 50

MYSPACE: Morganella morganii Yersinia enterocolitica Serratia Providencia/PSA Aeromonas Citrobacter freundii Enterobacter/Hafnia alvei