Antibiotics Flashcards Preview

Infectious Disease > Antibiotics > Flashcards

Flashcards in Antibiotics Deck (34)
1

What are the antibiotics that work by cell wall synthesis inhibition?

Beta-lactams
- penicillins
- cephalosporins
- carbapenums
- monobactams
Glycopeptides
- vancomycin
- teicoplanin

2

What antibiotics act by inhibiting protein synthesis through the 30s ribosomal sub unit?

Amino glycosides
Tetracyclines

3

What antibiotics act by inhibiting the 50s ribosomal sub-unit?

Chloramphenicol
Clindamycin
Macrolides
Fusidic acid

4

What antibiotics act by blocking folic acid synthesis?

Trimethoprim
Sulphonamides

5

What antibiotics act by inhibiting nuclei acid synthesis by DNA gyrase inhibition?

Fluroquinolones
- cirofloxacin, norfloxacin

6

What antibiotics inhibit nucleoside acid synthesis through RNA polymerase inhibition?

Rifamycin
- rifampicin

7

What are inhibitors of cell membrane function?

Colistin
Polyene anti fungal drugs
- amphotericin B, nystatin

8

What are the four mechanisms of antibiotic resistance?

1. Antibiotic inactivation through inactivating enzymes
2. Alteration AF antibiotic target sites
3. Decreased antibiotic permeability of the cell wall preventing drug access to target
4. Active antibiotic eflux from bacteria

9

What are some examples of inactivating enzymes?

B-lactamases
Amino glycoside modifying enzymes

10

What are some inhibitors of beta-lactamases?

Clavulanic acid
Tazobactam
Sulbactam

11

What are the antibiotics that exhibit inducible chromosomal mediated beta-lactamase production?

Enterobacter
Serratia
Citrobacter
Acinetobacter
Pseudomonas
Proteus vulgaris
Morganella morganii

12

What are the two main types of b-lactamase?

ESBL - extended spectrum B lactamases which have enzymes encoded by a plasmid which can be passed between bacteria
Inducible chromosomal mediated b lactamase production from escappm

13

What are the usual organisms that harbour ESBLs?

E.coli
Klebsiella pneumoniae

14

What antibiotics do ESBLs inactivate?

All cephalosporins

15

What antibiotics do the ESCAPPM group inactivate?

3rd generation cephalosporins

16

What is the mechanism of resistance of MRSA?

Alteration in penicillin binding proteins (PBP target site) meaning methicillin cannot bind and act on the bacteria

17

What is the concern with use of Rifampicin alone?

Rapid development of resistance due to single step mutations that reduce the affinity of rifampicin for the RNA polymerase

18

What is the difference in cell wall structure between gram positive and gram negatives?

Gram positive
- simple cell wall structure that drugs can easily penetrate
Gram negative
- more complex cell envelope that requires drugs to travel through porins

19

What are some examples of penicillin/b-lactamase inhibitor combinations?

Amoxicillin + clavulanate
Ticarcillin + clavulanate
Piperacillin + tazobactam (tazocin)

20

What are some examples of first generation cephalosporins?

Cephazolin
Cephalexin
Cephalothin

21

What are some second generation cephalosporins?

Cefaclor
Cefuroxime

22

What are some third generation cephalosporins?

Cefotaxime
Ceftriaxone
Ceftazidime

23

What is a fourth generation cephalosporin?

Cefepime

24

What carbapenem does not have action against pseudomonas?

Ertapenem

25

What is the mechanism of Vancomycin resistance in enterococci?

Van A, B and C genetic mutations which prevent binding of vancomycin to cell wall components

26

What is are some differences between Van A , B and C?

A - also resistant to Teicoplanin (another glycopeptide), can be transferred between strains
B - transferred between strains
C - not able to be transferred between strains

27

Types of enterococcus and resistance?

All enterococci are instrinsically resistant to cephalosporins

Faecium = more resistant
Faecalis = less resistant

Faecium is often resistant to amoxicillin and occasionally to Vancomycin
Faecalis is usually sensitive to amoxicillin

28

What drugs work via time above MIC?

B-lactams
Clindamycin
Macrolides
Linezolid

29

What drugs work via peak concentration above MIC?

Aminoglycasides - ie gentamicin

30

What drugs work as a AUC dependant killing?

Vancomycin
Fluroquinolones

31

What are examples of carbapenemases?

New Dehli metalloproteinase
Klebsiella pneumoniae carbapenemase

32

What are carbapenemases resistant to and how do you treat them?

Resistant to all B lactams
Treat with Colistin

33

What is a risk factor for development of Vancomycin resistant enterococci?

Use of anerobic cover - ie metronidazole
VRE genes are initally in anaerobes which are then killed and the enterococci takes up the genes and becomes VR

34

What drugs provide anaerobic cover?

Metronidazole
Augmentin/Tazocin (B-lactamases)
Clindamycin
Meropenum
Chloramphenicol