Antibiotics

Question 1

Bactericidal

Answer 1

lethal to bacteria

Question 2

Bacteriostatic

Answer 2

inhibits growth but is not lethal

Question 3

Minimal Inhibitory Concentration (MIC)

Answer 3

lowest concentration of antibiotic able to inhibit bacterial growth in a liquid medium
**Inhibits growth but bacteria may still be alive

Question 4

Mean Bactericidal Concentration (MBC)

Answer 4

the concentration of antibiotic that blocks all bacteria growth on plated samples
**No living organisms

Question 5

spectrum =

Answer 5

organisms that a prticular agent is active against

Question 6

Resistance =

Answer 6

microbes that are not inhibited by clinically achievable concentrations of abx

Question 7

Empiric therapy

Answer 7

abx given based on probable microbial etiology

* educated guess

Question 8

specific therapy =

Answer 8

specific antimicrobial therapy based on a known pathogen

Question 9

Contaminant =

Answer 9

culture data that suggests the organism came from the skin or environment and does not represent true infxn

Question 10

Colonization =

Answer 10

development of a new flora at an anatomic site that does not clinically fit with an infxn at that site

Question 11

Gram (+) pathogens =

Answer 11

Staph
Strep
Listeria
Bacillus 
Corbybacterium

Question 12

Gram (-) pathogens =

Answer 12

E. coli
Klebsiella
Proteus 
Pseudomonas 
Enterobacetr
Haemophilus 
Neissaria 
Salmonella

Question 13

Anaerobes

Answer 13

Clostridium

Bacteroides

Question 14

Bacterial cell wall abx

Answer 14

Beta lactams

Glycopeptides

Question 15

Protein synthesis Abx

Answer 15

Aminoglycosides 
Tetracyclines 
Macrolides 
Clindamycin 
Oxazolidinones

Question 16

Nucleic acid synthesis abx

Answer 16

Quinolones
Folate inhibs
Metronidazole

Question 17

Cell membrane Abx

Answer 17

daptomycin

Question 18

Cell wall synthesis inhibitors abx

Answer 18

1) Beta lactams (PCNs, Cephalosporins, Carbapenems, Monobactams)
2) Glycopeptide antimicrobials (Vancomycin)

Question 19

B lactam mechanism of action

Answer 19

• inhibits transpeptidation: blocks cross linking of peptidoglycan units
• Look like Ala-Ala
• Bactericidal
• Bacteria must be synthesizing new cell wall for this to be effective
• Kill bacteria by osmotic lysis : water enters cell from extracellular space and causes rupture

Question 20

Penicillin G

Answer 20

• Gram + organisms and spirochetes
• acid sensitive: NO ORAL
• least toxic and least expensive
• Benzathine PCN (Bicillin)= long acting form, lasts 7-10 days in body IM

Question 21

PCN V

Answer 21

• chemical modification of PCN G
• Acid stable so can give orally
• covers mouth flora and strep throat

Question 22

B lactamase resistant PCNS

Answer 22

• Methicillin, Oxacillin, Nafcillin
• active against lactamase producing S. Areus (MSSA)
• mostly used in cellulitis

Question 23

Aminopenicillins

Answer 23

1) Amoxicillin
2) Ampicillin
3) Amoxicillin/clavulinic acid = augmentin
4) Ampicillin-sulbactam = unasyn

Question 24

Amoxicillin

Answer 24

• oral
• tastes great: kids
• Otitis media and sinusitis: Moraxella, H. Influenza, Streptococcus

Question 25

Ampicillin

Answer 25

• IV only

- Used for listeria and Enterococcus

Question 26

Amoxicillin/Clavulinc acid = augmentin

Answer 26

• B lactamase producing Moraxella and H influenza
• Used as tx for failed otitis media or sinusitis
• Clavulinic acid inhibits beta lactamase

Question 27

Ampicillin-Sulbactam = Unasyn

Answer 27

-If worried about B lactam producing bacteria

Question 28

Carboxy/ureido PCNs

Answer 28

= Ticarcilllin-clavulante and Pipercillin-tazobactam

• Extended spectrum
• covers Pseudomonas, Bacteroides and Enterobacter
• Anaerobic: Intra-abdominal infxns and Gynecologic infxns
• Can also be used for life or limb threatening skin infxns with both Gram -/+ organisms