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Phase 2a - Kate > Antibiotics > Flashcards

Flashcards in Antibiotics Deck (75):
1

5 methods of antibiotic resistance are:

1. Target site mutation - change in molecular configuration of antimicrobial binding site
2. Destruction of antimicrobial - e.g. B-lacatamase enzyme
3. Prevention of antimicrobial entry - modification to membrane porin channel size
4. Removal of anti-microbial from bacterium

2

MRSA resistance mechanism

Methicillin Resistant Staphylococcus Aureus.
mecA gene encodes for penicillin binding protein 2a (PBP2a) - a mutation to this means penicillin can't bind

3

VRE resistance mechanism

Vancomycin resistant Enterococci
- plasmid mediated gene for altered a.a. on peptide chain prevents vancomycin form binding

4

Gram negative B-lactamases resistance mechanism

The bacterium produce b-lactamase which hydrolyse the b-lactam ring of penicillin and cephalosporins
NB// typically remain sensitive to B-lactamase inhibitors

5

ESBL resistance

Extended spectrum B-lactamases
- further mutations and the active site (B-lactam ring) means they can also inactivate:
a. celphalosporins
b. combination antibiotics (co-amoxiclav)

6

Antibiotic classes specific to GRAM -ve bacteria

- aminoglycosides (streptomycin/gentamycin; inhibit protein synthesis)
- trimethoprim (inhibit folate synthesis)

7

Antibiotic classes specific to GRAM +ve bacteria

- penicillins (amoxicillin) - disrupt peptidoglycan synthesis
- macrolides (clarithromycin, erythromycin) - inhibit protein synthesis
- lincosamide (clindamycin) - inhibits protein synthesis
- glycopeptides (vancomysin/teicoplasin)

8

Common uses of Macrolides

P - pneumonia
U - URI
S - STD
(clarithromycin/erythromycin)

9

Common uses of ceftriazone

a cephalosporin (generational classes,, higher generation = broader)
--> gonococcus
--> meningococcus

10

Common uses of vancomycin

a glycopeptide (target cell wall - monitor nephrotoxicity)
-->MRSA
-->enterococci
(some resistance e.g. VRE)

11

Common uses of doxycycline

Lyme disease, Rickessetia, malaria prophylaxis, exacerbation of COPD, chlamydia
- broad spectrum tetracycline

12

Treatment of TB

R - rifampicin
I - isoniazide
P - pyrazinamide
E - ethambutol

13

Use of metronidaozole

anaerobic infections - INTRA-ABDOMINAL, pelvic, oral, soft tissue
inhibits nucleic acid synthesis
- gram +/- ve

14

Mechanism of Penicillins

B-lactam rings. Inhibition of peptidoglycan cross linking -> disruption of gram +ve cell wall synthesis

15

Indications for Benzylpenecillin

Streptococcal infection, clostridial infection, meningococcal infection.

16

Contraindications and interactions to benzylpenecillin

Penicillin Allergy; interaction with methotrexate - excretion impaired -> toxicity

17

What it the mechanism for flucloxacillin resistance

Penicillinase-resistant: side chain protects from B-lactamase

18

Indications for flucloxacillin

Staphlococcal infection, osteomyelitis, septic arthritis

19

Indications for amoxicillin

Empirical treatment of pneumonia, UTI

20

Contraindications against flucloxacillin

penicillin allergy, previous liver toxicity

21

Contraindications against amoxicillin

Penicillin allergy, severe renal impairment

22

What forms co-amoxiclav?

amoxicillin & clavulanic acid

23

Why is co-amoxiclav used, instead of other penicillins.

its broad-spectrum, clavulanic acid is a B-lactamase inhibitor

24

Indications for co-amoxiclav.

Hospital acquired infections, intra-abdominal sepsis. H.pylori

25

Contraindications and interactions of amoxicillin,

CI: penicillin, severe renal impairment;
Interactions: methotrexate, excretion impaired -> toxicity

26

Indications for piperacillin + tazobactam (tazocin)

severe broad spectrum infection, Pseudomonas, immunocompromised

27

Indications for Cefotaxime

urinary and respiratory tract infections

28

Contraindications and interactions of cefotaxime

CI: penicillin allergy;
Interactions: increases warfarin action, increases nephrotoxicity in aminoglycosides

29

Mechanism of Macrolides

Macrolides inhibit bacterial protein synthesis

30

2 examples of macrolides

Erythromycin, and clarithromycin. Oral & IV

31

Indications for macrolides

Resp & skin (if penicillin allergy), severe pneumonia, peptic ulcer (eradicate H.pylori)

32

Contraindications, and interactions and adverse effects for macrolides.

CI: macrolide hypersensitivity
Interactions: drugs metabilised by CYTP450; Adverse effects: irritant (nausea)

33

MOA of quinolones

Inhibits DNA synthesis

34

Example of quinolones

ciprofloxacin or moxifloxacin

35

Formation of resistance of quinolones

bacteria rapidly develop resistance (2nd or 3rd line)

36

Indications for quinolones

UTI, severe GI infection (shigella, campylobacter), lower UTI, malaria.

37

Contraindication, interactions and adverse effects for quinolones

CI: seizures, growing, cardiac disease;
Interactions: theophylline;
AE: GI upset, C.difficile colitus

38

Mechanism of action of metronidazole

inhibits bacterail DNA synthesis, anaerobic bacteria activate it. IV, oral, PR

39

Indications for metronidazole

protozoal infection, anaerobes, H. pylori (with macrolide), C. difficile

40

Contraindications of metronidazole

liver disease
don't use with alcohol

41

Metronidazole interactions and adverse effects

Interactions: warfarin, phenytoin, cytochrome P450;
no significant adverse effects

42

MOA of antifungals

Binds to fungal membrane protein ergosterol

43

Examples of antifungals and route of administration

Nystin, clotrimazole, fluconazole;
oral or topical

44

Indication & Contraindications for fluconazole

Indications - fungal infection
Contraindications - liver disease

45

Drug interactions for fluconazole

drugs metabolised by cytochrome P450

46

Mechanism of action of nitrofurantoin

Activated in bacterial cells, damages DNA.

47

Indication for use of nitofurantoin

Uncomplicated LUTI (concentrates in urine)

48

MOA of aminoglycosides

inhibits 30s ribosomal unit --> no bacterial protein synthesis

49

3 examples of aminoglycosides

- gentamycin
- neomycin
- streptomycin

50

Indications for aminoglycosides

serious GRAM -VEs. Pseudomonas, severe sepsis, pylonephritis, endocarditis, NOT anaerobes

51

Contraindications for gentamycin

Myasthenia gravis

52

Aminoglycoside interactions and adverse effects

Interactions: furisemide
Adverse effects: ototxicity, nephrotoxicity

53

Vancomycin mechanism of action

inhibits peptidoglycan cross linking --> disruption of gram +ve cell wall synthesis

54

Is Vancomycin 1st or 2nd line treatment?

Vancomycin is 2nd line following resistance.

55

indications for vancomycin

severe c.diff, MRSA, Gram +ve aerobic an anaerobic e.g. endocarditis

56

vancomycin interactions and adverse effects

I's: aminoglycosides and loop diuretics
AE: ototxicity, nephrotoxicity

57

MOA of tetracyclines

Inhibits 30s ribosomal unit -> no bacterial protein synthosis

58

2 examples of tetracyclines

- doxycycline
- lymecycline

59

Indications for tetracyclines

Acne vulgaris, lower resp tract infection -> H. influenzae, pneumonia

60

Contraindications for tetracyclines

Preg, breastfeeding, children <12, renal impairment

61

Interactions for tetracyclines

Ca2+, Fe2+, antacids, bind to tetracyclines --> not absorbed.
increase the effect of warfarin (kill Vit K secreting bacteria)

62

Adverse effects of tetracyclines

nausea, vomiting, diarrhoea.

63

2 examples of trimethoprims

- trimethoprim
- co-trimoxazole

64

MOA of trimethoprim

inhibits bacterial folate synthesis. Bacteriostatic

65

MOA of co-trimoxazole

Inhibits bacterial folate synthesis, combines with sulfamethoxazole for bactericidal activity.
Bactericidial.

66

Indications for trimethoprim

uncomplicated UTI, first line.

67

Indications for co-trimoxazole

Pneumocycstis pneumonia in the immunosuppressed

68

Contraindications of trimethoprim

Folate deficiency

69

Trimethoprim interactions and adverse effects

Interactions: Potassium elevating drugs
Adverse effects: rash

70

Mechanism of action of quinines

Reduces excitability of motor end plate; unknown function in relation to malaria

71

Examples of quinines

quinine sulphate

72

Indications for quinines

- noctural leg cramps
- no longer 1st line for Malaria

73

Contraindications for quinines

hearing loss

74

Interactions of quinines

Arrythmia medication.

75

Adverse effects of quinine

Tinnitus, deafness, blindness.