M16 mechanisms of Antibiotic resistance

Question 1

what is the trend of evolution of resistance to antibiotics?

Answer 1

highest outpatient use of penecillin correlates with highest frequency of resistant bacteria

Question 2

how can drug resitance arise?

Answer 2

by mutation or gene transfer

resistance provides a selective advantage

Question 3

describe a mechanism of antimicrobial drug resistance

Answer 3

inactivation
- Beta-lactamase ;
extended spectrum B-lactamase (ESBL)

Question 4

list 2 Beta-lactamases

Answer 4

ESBL

metalloenzyme - inactivate penecillins, cephalosporins and carbapenems

Question 5

describe a metalloenzyme

Answer 5

New Delhi Metallo Beta-Lactamase 1 (NDM-1)

- carbapenamase

Question 6

what was the last line of treatment for NDM-1

Answer 6

Colistin

Question 7

how does vancomycin block access substrate?

Answer 7

binds terminal D-ala D-ala

Question 8

how does metronidazole carry out the reduction of the Nitro group?

Answer 8

metronidazole captures electrons that would be transferred to 2H+ –> 1 electron reduction means Met decomposes to produce NO2- –> damage to enzymes, proteins and DNA

Question 9

prescribing of antibiotics must be kept to a minimum

Answer 9

true

Question 10

before prescribing antibiotics, what are the local measures?

Answer 10

first step use local measures:
drain pus by extraction or root canal (dental abscesses)
or drain pus by incision (soft tissue infections)

pulpitis and dry socket infections;
no evidence to support prescription in healthy (immuno-competent) patients

Question 11

dental abscess

Answer 11

amoxicillin capsules 250mg

15 capsules - 5 days

Question 12

for patients with a dental abscess and are allergic to patients

Answer 12

erythormycin tablets, 250 mg

20 tabs - 1 tablet 4 times daily