Case Studies (Buxton/Habal)

Question 1

What organism causes strep throat?

Answer 1

Staph pyogenes (GAS)

Question 2

Which antibiotics are used for the treatment of Strep throat?

Answer 2

amoxicilliin

penicillin (give upset stomach)

Question 3

What is the mechanism of action for amoxicillin?

Answer 3

inhibit transpeptidase which inhibits cell wall synthesis

Question 4

What symptoms might be present with strep throat?

Answer 4

fever
exudative pharyngitis
headache

Question 5

Which organisms cause otitis media?

Answer 5

H. flu
Moraxella
resistant Strep pneumo

Question 6

Why are H. flu and Moraxella resistant to amoxicillin?

Answer 6

they produce b lactamase

Question 7

Why would Clavulanate be paired with amoxicillin?

Answer 7

it is a b-lactamase inhibitor

Question 8

Which organism would cause a post-surgical skin infection?

Answer 8

Staph

Strep

Question 9

Which antibiotics are often used to treat Staph and Strep?

Answer 9

Nafcillin (anti Staph)
1st/2nd generation cephalosporin
1st- Cefazolin - IV
2nd - Cefuroxime - IV

Question 10

What is the mechanism of action of Nafcillin and cephalosporins?

Answer 10

Cell wall inhibitors that act by binding to D-ala-D-ala bonds to prevent cross linking

Question 11

Is there antibiotic resistance with Nafcillin and cephalosporin? mechanism:

Answer 11

Yes, altered PBPs

Question 12

Diagnsosis of acute uncomplicated cystitis. What is the most likely cause?

Answer 12

E coli

Question 13

Which drugs could be used to treat UTIs?

Answer 13

1st/2nd gen cephalosporin:
cephalexin (oral)
cefuroxime (oral)
TMP/SMX
Cipro (Fluoroquinolone)
ampicillin

Question 14

What is mechanism of action for cephalosporins TMP/SMX, Cipro or ampicillin?

Answer 14

cell wall synthesis inhibitors

inhibits DNA gyrase (?)

Question 15

If pregnant, which drugs would you not give for UTI?

Answer 15

TMP/SMX

Fluoroquinolones

Question 16

Which organisms cause native valve endocarditis?

Answer 16

Staph Aureus
Staph Epidermidis
Strep Viridans

Question 17

What are some empiric therapies for Staph Aureus, Staph Epiderminid, or Strep Viridans

Answer 17

ceftriaxone

vancomycin ??

Question 18

What is the most likely definitive treatment for a viridans group streptococci that is susceptible to all tested antibiotics?

Answer 18

Penicillin G + Gentamycin (for anaerobic gram negative)

ceftriaxone (3rd?)

Question 19

Developed community acquired bacterial pneumonia. What are the top 6 causes?

Answer 19

Strep pneumo
H. influenza
Legionella pneumophilia
Chlamydia pneumo
Moraxella
mycoplasma pneuomoni

Question 20

What are some likely empiric regimens for CA bacterial pneumonia?

Answer 20

ceftriaxone + azithromycin (or another macrolide…clarithromycin, erythromycin )
fluoroquinalone

Question 21

How does ceftriaxone and azithromycin work?

Answer 21

Ceftriaxone - inhibits cell wall synthesis

Macrolides - inhibit protein synthesis

Question 22

How is antibiotic resistance determined in the lab?

Answer 22

AGAR disc diffusion

Question 23

Student develops sepsis from ruptured appendix. Which organism could be involved?

Answer 23

Enterococcus
E. coli
Klebsiella
bacteroids

Question 24

Which antibiotics are commonly used when you need a broad spectrum antibiotic against gram positive and gram negative aerobes and anaerobic bacteria?

Answer 24

piperacillin
ticarcillin
carbenicillin

+ tazobactam

Question 25

Woman develops PID. What are the most common organisms causing PID?

Answer 25

N. gonorrhea Chlamydia trachomatic bacteroides

Question 26

Which antibiotics are most likely used to treat PID?

Answer 26

3rd gen cephalosporin - ceftriaxone (for N gonorrhea or bacteroides Tetracycline/doxycycline (for C. trachomatis)

Question 27

Man acquired HA pneumonia. MRSA was isolated from aspirated sputum. Which drug could be used to treat this patient?

Answer 27

vancomycin

Question 28

What is the mechanism of antibiotic resistance for MRSA?

Answer 28

mutated/altered PBP

Question 29

Man developed sepsis after hospitalization for prostate cancer surgery. Cultures grew Pseudomonas aeruginosa. Is this CA or HA acquired infection?

Answer 29

HA Pseudomonas aeruginosa

Question 30

What are the drugs that could be used for a HA Pseudomonas aeruginosa?

Answer 30

Carbapenums, or piperacillin + tazobactum 3rd/4th gen cephalosporin Ceftriaxone Cefepime

Question 31

What drug should not be used if the patient has kidney disease?

Answer 31

fluoroquinolones (inhibit DNA gyrase) | cipro

Question 32

What drug would be used if he was allergic to penicillin?

Answer 32

macrolides??

Question 33

Inmate developed fever, weakness chills, weight loss and cough productive bloody sputum. What is the most likely etiology?

Answer 33

Mycobacterium tuberculosis (TB)

Question 34

What is the antibiotic regimen for TB?

Answer 34

RIPE