Antibiotic Resistance Flashcards Preview

Block 5 Drugs > Antibiotic Resistance > Flashcards

Flashcards in Antibiotic Resistance Deck (25)
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1

What is intrinsic resistance?

Intrinsic resistance is a quality that a bacteria naturally has to prevent the drug from penetrating or acting on it
- Lack of drug targets or lack of access to drug targets

2

What is acquired resistance?

Genetic variability allows bacteria to become resistant to an antibiotic that used it to be sensitive to

3

What is constitutive resistance?

Bacterial mechanism is consistently present and usually essential to bacterial function

4

What is inducible resistance?

Resistance gene turned on in response to environmental stimuli (e.g. antibiotics) => Expanded-spectrum beta-lactamases in E. coli

5

What are examples of single nucleotide base pair mutations?

1) Quinolone resistance:
-Point-mutations in DNA gyrase or topoisomerase
2) Evolution of beta-lactamases in gram-negatives
-Families differ by many AA’s. Within families, isoenzymes differ from each other by single or several AA’s.

6

What is the mechanism behind larger DNA rearrangement (jumping genes) bacterial resistance?

Transposable DNA segments prone to rearrangement in bacterial chromosome or plasmid DNA

7

What is the mechanism behind acquisition of DNA from other bacteria as a means of bacterial resistance?

- Foreign DNA containing resistance genes can be acquired from plasmids, bacteriophages, and transposable genetic elements
- Conjugation, transduction, transformation allow genetic material to move within populations of bacteria and is perpetuated over time

8

How do bacteria survive antibiotic exposure?

1) Alter drug permeability
2) Alter drug targets
3) Inactivate of drug
4) Active efflux

9

What are the dominant resistance mechanisms to cell wall synthesis blocking antibiotics?

1) Altered penicillin-binding proteins (ie Streo Pneumonia)
2) Modified cell wall targets (Vancomycin resistant enterococcus)

10

What is the major resistance mechanism to quinolines?

1) Altered gyrase or topoisomerases

11

What are the major resistance issues of S. aureus?

1) Beta-lactamase
2) Altered PBPs (MRSA, mecA gene+)

12

What drug should be used for resistance S. aureus?

Vancomycin

13

What are the major resistance issues of Strep. pneumonia?

Altered PBPs

14

What drugs should be used for resistant Strep. pneumoniae?

1) Meningitis or Sepsis: Vancomycin/Ceftriaxone
2) Pneumonia: Ceftriaxone

15

What is the major resistance issue of Group A strep?

Erythromycin resistance

16

What drugs should be used for resistant Group A Strep?

Penicillin or cefazolin

17

What are the major resistance issues of N. meningitides?

-Beta-lactamase
-Altered PBPs

18

What drugs should be used for resistant N. meningitides?

Ceftriaxone

19

What are the major resistance issues of H. influenzae?

Beta-lactamase production

20

What drugs should be used for resistant H. influenzae?

Ceftriaxone or beta-lactam + beta-lactamase inhibitor combinations

21

What are 3 main ways of managing MRSA infections?

1) Incision and drainage
2) Use of cultures
3) Foreign body/device removal (if in place >30 days)

22

What are the common gram negative rods that carry a lot of drug resistance?

1) Enterobacteriaceae => E. coli, Klebsiella, Enterobacter, (Serratia, Proteus, Citrobacter, Salmonella)
2) Acinetobacter
3) Pseudomonas

23

What risks are associated with gram negative rod resistance?

>Hospital stay, ICU, longterm care facility, central lines and urinary catheters, abdominal surgery, prior antibiotics, ventilator, dialysis

24

Gram negative rods generally carry resistance to which drug group?

Beta lactams (Penicillinase and Cephalosporinases, Carbapenemases)

25

What populations are at increased risk of multi drug resistant acinetobacter?

1) Health-cares associated infections:
- Mostly VAP and bloodstream infections
- Common source outbreaks related to respiratory and ventilator equipment
2) Military personnel
3) Disasters
4) Community outbreaks