Antibiotics

Question 1

Beta-lactams

Answer 1

Penicillins (natural, antistaphylococcal, extended-spec, and antipseudomonal)
Cephalosporins (1-5)
Carbapenems
Monobactams

Question 2

Cell-wall synthesis inhibitors

Answer 2

beta-lactams (PBPs = no synthesis of stable cell wall), vanco (transglycosylase = prevent binding of peptidoglycans, bacitracin (interferes with transport across cell)
Bactericidal, time-dependent

Question 3

Cell membrane disruption

Answer 3

polymyxin, daptomycin

Question 4

Classes that inhibit protein synthesis

Answer 4

Tetracyclines (30S), macrolides (50S), and aminoglycosides (30S - bactericidal)

Question 5

Classes that inhibit nucleic acid synthesis

Answer 5

RNA polymerase inhibitor - rifampin

DNA replication inhibitor - Fluoroquniolones (cirpfloxacin)

Question 6

Classes that inhibit folic acid synthesis

Answer 6

Trimethoprim and sulfonamides (sulfamethoxazole)

Question 7

Streptococcus treatments

Answer 7

Penicillin V
Amoxicillin
Cephalexin
Amoxicillin+clavulanic acid

Allergy to beta-lactam: azithromycin, clarithromycin, clindamycin

Question 8

MSSA treatments

Answer 8

Nafcillin
Oxacillin
Dicloxacillin
Cephalexin
Amoxicillin+clauvulanic acid
3rd gen cephalosporins for severe infections

Allergy to beta-lactams: azithromycin, clarithromycin, clindamycin

Question 9

MRSA treatments

Answer 9

Ceftaroline (moderate)
Vanco (severe)
Dapto (severe)
SMX/TMP (mild-moderate)
Doxy (moderate)
Minocycline (moderate)
Clindamycin (moderate)
Linezolid (severe)

Question 10

Extended spectrum penicillins treat these gram-

Answer 10

Haemophilus influenzae
Heliobacter pylori
Escherichia coli
Listeria monocytogenes
Proteus mirabilis
Salmonells
Shigells
Enterococci
(HHELPSSE)

Question 11

Superinfection

Answer 11

• Broad-spectrum antibiotics (frequent: extended-spec penicillins, cephalosporins, clindamycin, fluoroquinolones; occasionally: TMP/SMX, macrolides)
• organisms: Clostridium difficile (pseudomembranous colitis), Staphylococcus aureus (entercolitis), candida albicans (vagina and mouth infections)

Question 12

Activity of cephalosporins moving from 1st to 4th gen

Answer 12

Increasing activity against g-, beta-lactamase, pseudomonas, anaerboes; increasing ability to cross BBB

Question 13

1st gen cephalosporins

Answer 13

• Cephalexin, cefazolin
• g+ (staph and strep, PEcK - proteus mirabilis, E.coli, and Klebsiella pneumoniae
• UTI
• SSTI caused by staph and strep like cellulitis or abscess

Question 14

Vancomycin use

Answer 14

MRSA, Enterocolitis, C. diff, enterococci

Question 15

Vanco adverse effects

Answer 15

Nephrotoxicity
Ototoxicity
Thrombophlebitis
Red man syndrome - histamine release (pre-treat with anti-histamine and slow infusion rate)

Question 16

Vanco resistance

Answer 16

D-ala-D-ala to D-ala-D-lactate

Question 17

Dapto clinical use

Answer 17

Staph aureus (including MRSA), enterococcus faecalis and faecium, strep pyogenes (GAS)

Question 18

Dapto major side effects

Answer 18

Myopathy (elevated CK)

Question 19

Spectrum of polymyxins

Answer 19

g- (mostly aerobes - pseudomonas)

Question 20

Clinical use of polymyxins

Answer 20

Significant toxicity with systemic use so topical; systemic use limited to serious infections

Question 21

Side effects of polymyxin

Answer 21

Nephrotoxicity and neurotoxicity

Question 22

SMX and TMP MOA

Answer 22

p-Aminobenzoic acid converted to dihydropteroic acid via dihydropteroate synthase (inhibited by sulfonamides); dihydropteroic acid converted to dihydrofolate via dihydrofolate reductase (inhibited by trimethoprim)

Question 23

SMX/TMP clinical use

Answer 23

• MSSA and mild-moderate MRSA
• UTI
• respiratory tract infections (H. influenzeae, strep pneumoniae - increased resistance)
• enterocolitis (shigella)
• traveler’s diarrhea (E. coli and shigella)
• otitis media

Question 24

SMX side effects

Answer 24

Allergies (fever, nausea, vomiting, diarrhea, rash, dermatitis, Steven Johnson syndrome); hematological disorders (megaloblastic anemia, leukopenia, granulocytopenia, thrombocytopenia, hemolytic anemia in pt with G6PD deficiency)

Question 25

Side effect unique to SMX

Answer 25

kernicterus in newborns (drug displaces bilirubin from albumin>>free bilirubin deposist in basal ganglia and subthalamic nuclei>>encephalopathy

Question 26

Tetracyclines MOA

Answer 26

Bind to 30S of bacterial ribosome, blocking access of aminoacyl-tRNA to mRNA-ribosome complex

Question 27

Clinical use of tetracyclines

Answer 27

MRSA, anthrax, mycoplasma pneumonia, chlamydia, rickettsiae, Lyme, GI

Question 28

Tetracyclines side effects

Answer 28

GI distress, photosensitivity, discoloration of teeth in children, inhibition of bone growth in children (tetracycline binds to Ca)

Question 29

Macrolides MOA

Answer 29

Binds to 50S to inhibit peptide transfer

Question 30

Macrolides clinical use

Answer 30

Substitute for penicillins, strep and staph (not MRSA), more on g-

Question 31

Major side effects of macrolides

Answer 31

``` MACRO gi Motility Arrythmia acute Cholestatis hepatitis Rash eosinOphilia ```

Question 32

Clindamycin MOA

Answer 32

50S subunit

Question 33

Clindamycin clinical use

Answer 33

strep and staph; anaerobic infections

Question 34

Side effects of clindamycin

Answer 34

Fever, diarrhea, superinfection: pseudomembranous colitis

Question 35

Linezolid MOA

Answer 35

50S

Question 36

Clinical use of linezolid

Answer 36

broad g+ MRSA VRE

Question 37

Side effects of linezolid

Answer 37

bone marrow suppression (thrombocytopenia, anemia, neutropenia), optic and peripheral neuropathy, serotonin syndrome when administered with SSRIs